Provide SCIM2 client capabilities behing an experimental Feature Profile

Closes #1234

Signed-off-by: Alex Morel <amorel@codelutin.com>

common/src/main/java/org/keycloak/common/Profile.java

@@ -112,6 +112,8 @@ public class Profile {
 
         OID4VC_VCI("Support for the OID4VCI protocol as part of OID4VC.", Type.EXPERIMENTAL),
 
+        SCIM("Synchronise users and groups with registered SCIM endpoints", Type.EXPERIMENTAL),
+
         OPENTELEMETRY("OpenTelemetry Tracing", Type.PREVIEW),
 
         DECLARATIVE_UI("declarative ui spi", Type.EXPERIMENTAL),

dependencies/server-all/pom.xml

@@ -70,6 +70,11 @@
             <groupId>org.keycloak</groupId>
             <artifactId>keycloak-kerberos-federation</artifactId>
         </dependency>
+        <!-- SCIM federation -->
+        <dependency>
+            <groupId>org.keycloak</groupId>
+            <artifactId>keycloak-scim-federation</artifactId>
+        </dependency>
         <!-- saml -->
         <dependency>
             <groupId>org.keycloak</groupId>

docs/documentation/server_admin/topics/user-federation/scim.adoc

@@ -0,0 +1,72 @@
+[[_scim]]
+
+=== SCIM client capabilities
+
+{project_name} includes a http://www.simplecloud.info[SCIM2] client allowing to :
+
+* Declare SCIM endpoints (through the identity federation UI). Any tool implementing SCIM protocol can be wired to the
+{project_name} instance through this declaration.
+* Propagate users and groups from {project_name} to SCIM endpoints : when a user/group gets created or modified in {project_name},
+the modification is forwarded to all declared SCIM endpoints through SCIM calls within the transaction scope. If
+propagation fails, changes can be rolled back or not according to a configurable rollback strategy.
+* Synchronize users and groups from SCIM endpoints (through the {project_name} synchronization mechanism).
+
+See [RFC7643](https://datatracker.ietf.org/doc/html/rfc7643)
+and [RFC7644](https://datatracker.ietf.org/doc/html/rfc7644)) for further details
+
+==== Enabling SCIM extension
+
+[NOTE]
+====
+This extension is currently in experimental mode, and requires the ```SCIM``` experimental Profile to be enabled
+====
+
+.Procedure
+. Click on *Admin Console > Realm Settings > Events* in the menu.
+. Add `scim` to the list of event listeners
+image:images/scim-event-listener-page.png[Enable SCIM Event listeners]
+. Save
+
+==== Registering SCIM Service Providers
+
+.Procedure
+. Click on *User federation > Add Scim Providers*
+image:images/scim-federation-provider-page.png[Configure SCIM service provider]
+. Fill required fields according to the SCIM endpoint you are wiring
+. If you enable import during sync then you can choose between to following import actions:
+
+- Create Local - adds users to keycloak
+- Nothing
+- Delete Remote - deletes users from the remote application
+
+==== Sync
+
+You can set up a periodic sync for all users or just changed users - it's not mandatory. You can either do:
+
+- Periodic Full Sync
+- Periodic Changed User Sync
+
+
+==== Technical notes
+
+===== Motivation
+
+We want to build a unified collaborative platform based on multiple applications. To do that, we need a way to propagate
+immediately changes made in Keycloak to all these applications. And we want to keep using OIDC or SAML as the
+authentication protocol.
+
+This will allow users to collaborate seamlessly across the platform without requiring every user to have connected once
+to each application. This will also ease GDRP compliance because deleting a user in Keycloak will delete the user from
+every app. The SCIM protocol is standard, comprehensible and easy to implement. It's a perfect fit for our goal.
+
+We chose to build application extensions/plugins because it's easier to deploy and thus will benefit to a larger portion
+of the FOSS community.
+
+===== Keycloak specific
+
+This extension uses 3 concepts in KeyCloak :
+
+- Event Listener : used to listen for changes within Keycloak (e.g. User creation, Group deletion...) and propagate
+them to registered SCIM service providers through SCIM requests.
+- Federation Provider : used to set up all the SCIM service providers endpoint without creating our own UI.
+- JPA Entity Provider : used to save the mapping between the local IDs and the service providers IDs.

federation/pom.xml

@@ -36,6 +36,7 @@
         <module>kerberos</module>
         <module>ldap</module>
         <module>sssd</module>
+        <module>scim</module>
     </modules>
 
 </project>

federation/scim/pom.xml

@@ -0,0 +1,83 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+
+    <parent>
+        <artifactId>keycloak-parent</artifactId>
+        <groupId>org.keycloak</groupId>
+        <version>999.0.0-SNAPSHOT</version>
+        <relativePath>../../pom.xml</relativePath>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>keycloak-scim-federation</artifactId>
+    <name>Keycloak Federation from SCIM endpoints</name>
+    <description>
+        This extension add SCIM2 client capabilities to Keycloak.
+        It allows to :
+        * Declare SCIM endpoints (through the identity federation UI). Any tool implementing SCIM protocol can be wired to the
+        Keycloak instance through this declaration.
+        * Propagate users and groups from Keycloak to SCIM endpoints : when a user/group gets created or modified in Keycloak,
+        the modification is forwarded to all declared SCIM endpoints through SCIM calls within the transaction scope. If
+        propagation fails, changes can be rolled back or not according to a configurable rollback strategy.
+        * Import users and groups from SCIM endpoints (through the Keycloak synchronization mechanism).
+        See [RFC7643](https://datatracker.ietf.org/doc/html/rfc7643)
+        and [RFC7644](https://datatracker.ietf.org/doc/html/rfc7644)) for further details
+    </description>
+
+    <properties>
+        <scim-sdk-version>1.26.0</scim-sdk-version>
+        <r4j-version>2.2.0</r4j-version>
+        <maven-wildfly-plugin.version>2.0.2.Final</maven-wildfly-plugin.version>
+    </properties>
+    <dependencies>
+        <dependency>
+            <groupId>org.keycloak</groupId>
+            <artifactId>keycloak-core</artifactId>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.keycloak</groupId>
+            <artifactId>keycloak-server-spi</artifactId>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.keycloak</groupId>
+            <artifactId>keycloak-server-spi-private</artifactId>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.keycloak</groupId>
+            <artifactId>keycloak-services</artifactId>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.keycloak</groupId>
+            <artifactId>keycloak-model-jpa</artifactId>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.jboss.logging</groupId>
+            <artifactId>jboss-logging</artifactId>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>io.github.resilience4j</groupId>
+            <artifactId>resilience4j-retry</artifactId>
+            <version>${r4j-version}</version>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>de.captaingoldfish</groupId>
+            <artifactId>scim-sdk-common</artifactId>
+            <version>${scim-sdk-version}</version>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>de.captaingoldfish</groupId>
+            <artifactId>scim-sdk-client</artifactId>
+            <version>${scim-sdk-version}</version>
+            <scope>provided</scope>
+        </dependency>
+    </dependencies>
+
+</project>

federation/scim/src/main/java/sh/libre/scim/core/ScimDispatcher.java

@@ -0,0 +1,171 @@
+package sh.libre.scim.core;
+
+import org.jboss.logging.Logger;
+import org.keycloak.component.ComponentModel;
+import org.keycloak.models.KeycloakSession;
+import sh.libre.scim.core.exceptions.ScimExceptionHandler;
+import sh.libre.scim.core.exceptions.ScimPropagationException;
+import sh.libre.scim.core.exceptions.SkipOrStopApproach;
+import sh.libre.scim.core.exceptions.SkipOrStopStrategy;
+import sh.libre.scim.core.service.AbstractScimService;
+import sh.libre.scim.core.service.GroupScimService;
+import sh.libre.scim.core.service.UserScimService;
+
+import java.util.ArrayList;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Optional;
+import java.util.Set;
+
+/**
+ * In charge of sending SCIM Request to all registered Scim endpoints.
+ */
+public class ScimDispatcher {
+
+    private static final Logger LOGGER = Logger.getLogger(ScimDispatcher.class);
+
+    private final KeycloakSession session;
+    private final ScimExceptionHandler exceptionHandler;
+    private final SkipOrStopStrategy skipOrStopStrategy;
+    private boolean clientsInitialized = false;
+    private final List<UserScimService> userScimServices = new ArrayList<>();
+    private final List<GroupScimService> groupScimServices = new ArrayList<>();
+
+
+    public ScimDispatcher(KeycloakSession session) {
+        this.session = session;
+        this.exceptionHandler = new ScimExceptionHandler(session);
+        // By default, use a permissive Skip or Stop strategy
+        this.skipOrStopStrategy = SkipOrStopApproach.ALWAYS_SKIP_AND_CONTINUE;
+    }
+
+    /**
+     * Lists all active ScimStorageProviderFactory and create new ScimClients for each of them
+     */
+    public void refreshActiveScimEndpoints() {
+        // Step 1: close existing clients (as configuration may have changed)
+        groupScimServices.forEach(GroupScimService::close);
+        groupScimServices.clear();
+        userScimServices.forEach(UserScimService::close);
+        userScimServices.clear();
+
+        // Step 2: Get All SCIM endpoints defined in Admin Console (enabled ScimStorageProviderFactory)
+        session.getContext().getRealm().getComponentsStream()
+                .filter(m -> ScimEndpointConfigurationStorageProviderFactory.ID.equals(m.getProviderId())
+                             && m.get("enabled", true))
+                .forEach(scimEndpointConfigurationRaw -> {
+                    try {
+                        ScrimEndPointConfiguration scrimEndPointConfiguration = new ScrimEndPointConfiguration(scimEndpointConfigurationRaw);
+
+                        // Step 3 : create scim clients for each endpoint
+                        if (scimEndpointConfigurationRaw.get(ScrimEndPointConfiguration.CONF_KEY_PROPAGATION_GROUP, false)) {
+                            GroupScimService groupScimService = new GroupScimService(session, scrimEndPointConfiguration, skipOrStopStrategy);
+                            groupScimServices.add(groupScimService);
+                        }
+                        if (scimEndpointConfigurationRaw.get(ScrimEndPointConfiguration.CONF_KEY_PROPAGATION_USER, false)) {
+                            UserScimService userScimService = new UserScimService(session, scrimEndPointConfiguration, skipOrStopStrategy);
+                            userScimServices.add(userScimService);
+                        }
+                    } catch (IllegalArgumentException e) {
+                        if (skipOrStopStrategy.allowInvalidEndpointConfiguration()) {
+                            LOGGER.warn("[SCIM] Invalid Endpoint configuration " + scimEndpointConfigurationRaw.getId(), e);
+                        } else {
+                            throw e;
+                        }
+                    }
+                });
+    }
+
+    public void dispatchUserModificationToAll(SCIMPropagationConsumer<UserScimService> operationToDispatch) {
+        initializeClientsIfNeeded();
+        Set<UserScimService> servicesCorrectlyPropagated = new LinkedHashSet<>();
+        userScimServices.forEach(userScimService -> {
+            try {
+                operationToDispatch.acceptThrows(userScimService);
+                servicesCorrectlyPropagated.add(userScimService);
+            } catch (ScimPropagationException e) {
+                exceptionHandler.handleException(userScimService.getConfiguration(), e);
+            }
+        });
+        // TODO we could iterate on servicesCorrectlyPropagated to undo modification on already handled SCIM endpoints
+        LOGGER.infof("[SCIM] User operation dispatched to %d SCIM server", servicesCorrectlyPropagated.size());
+    }
+
+    public void dispatchGroupModificationToAll(SCIMPropagationConsumer<GroupScimService> operationToDispatch) {
+        initializeClientsIfNeeded();
+        Set<GroupScimService> servicesCorrectlyPropagated = new LinkedHashSet<>();
+        groupScimServices.forEach(groupScimService -> {
+            try {
+                operationToDispatch.acceptThrows(groupScimService);
+                servicesCorrectlyPropagated.add(groupScimService);
+            } catch (ScimPropagationException e) {
+                exceptionHandler.handleException(groupScimService.getConfiguration(), e);
+            }
+        });
+        // TODO we could iterate on servicesCorrectlyPropagated to undo modification on already handled SCIM endpoints
+        LOGGER.infof("[SCIM] Group operation dispatched to %d SCIM server", servicesCorrectlyPropagated.size());
+    }
+
+    public void dispatchUserModificationToOne(ComponentModel scimServerConfiguration, SCIMPropagationConsumer<UserScimService> operationToDispatch) {
+        initializeClientsIfNeeded();
+        // Scim client should already have been created
+        Optional<UserScimService> matchingClient = userScimServices.stream().filter(u -> u.getConfiguration().getId().equals(scimServerConfiguration.getId())).findFirst();
+        if (matchingClient.isPresent()) {
+            try {
+                operationToDispatch.acceptThrows(matchingClient.get());
+                LOGGER.infof("[SCIM] User operation dispatched to SCIM server %s", matchingClient.get().getConfiguration().getName());
+            } catch (ScimPropagationException e) {
+                exceptionHandler.handleException(matchingClient.get().getConfiguration(), e);
+            }
+        } else {
+            LOGGER.error("[SCIM] Could not find a Scim Client matching User endpoint configuration" + scimServerConfiguration.getId());
+        }
+    }
+
+
+    public void dispatchGroupModificationToOne(ComponentModel scimServerConfiguration, SCIMPropagationConsumer<GroupScimService> operationToDispatch) {
+        initializeClientsIfNeeded();
+        // Scim client should already have been created
+        Optional<GroupScimService> matchingClient = groupScimServices.stream().filter(u -> u.getConfiguration().getId().equals(scimServerConfiguration.getId())).findFirst();
+        if (matchingClient.isPresent()) {
+            try {
+                operationToDispatch.acceptThrows(matchingClient.get());
+                LOGGER.infof("[SCIM] Group operation dispatched to SCIM server %s", matchingClient.get().getConfiguration().getName());
+            } catch (ScimPropagationException e) {
+                exceptionHandler.handleException(matchingClient.get().getConfiguration(), e);
+            }
+        } else {
+            LOGGER.error("[SCIM] Could not find a Scim Client matching Group endpoint configuration" + scimServerConfiguration.getId());
+        }
+    }
+
+    public void close() {
+        for (GroupScimService c : groupScimServices) {
+            c.close();
+        }
+        for (UserScimService c : userScimServices) {
+            c.close();
+        }
+        groupScimServices.clear();
+        userScimServices.clear();
+    }
+
+    private void initializeClientsIfNeeded() {
+        if (!clientsInitialized) {
+            clientsInitialized = true;
+            refreshActiveScimEndpoints();
+        }
+    }
+
+    /**
+     * A Consumer that throws ScimPropagationException.
+     *
+     * @param <T> An {@link AbstractScimService to call}
+     */
+    @FunctionalInterface
+    public interface SCIMPropagationConsumer<T> {
+
+        void acceptThrows(T elem) throws ScimPropagationException;
+
+    }
+}

federation/scim/src/main/java/sh/libre/scim/core/ScimEndpointConfigurationStorageProviderFactory.java

@@ -0,0 +1,165 @@
+package sh.libre.scim.core;
+
+import de.captaingoldfish.scim.sdk.common.constants.HttpHeader;
+import jakarta.ws.rs.core.MediaType;
+import org.apache.commons.lang3.BooleanUtils;
+import org.jboss.logging.Logger;
+import org.keycloak.component.ComponentModel;
+import org.keycloak.models.KeycloakSession;
+import org.keycloak.models.KeycloakSessionFactory;
+import org.keycloak.models.RealmModel;
+import org.keycloak.models.utils.KeycloakModelUtils;
+import org.keycloak.provider.ProviderConfigProperty;
+import org.keycloak.provider.ProviderConfigurationBuilder;
+import org.keycloak.storage.UserStorageProvider;
+import org.keycloak.storage.UserStorageProviderFactory;
+import org.keycloak.storage.UserStorageProviderModel;
+import org.keycloak.storage.user.ImportSynchronization;
+import org.keycloak.storage.user.SynchronizationResult;
+import sh.libre.scim.event.ScimBackgroundGroupMembershipUpdater;
+
+import java.util.Date;
+import java.util.List;
+
+/**
+ * Allows to register and configure Scim endpoints through Admin console, using the provided config properties.
+ */
+public class ScimEndpointConfigurationStorageProviderFactory
+        implements UserStorageProviderFactory<ScimEndpointConfigurationStorageProviderFactory.ScimEndpointConfigurationStorageProvider>, ImportSynchronization {
+    public static final String ID = "scim";
+    private static final Logger LOGGER = Logger.getLogger(ScimEndpointConfigurationStorageProviderFactory.class);
+
+    @Override
+    public String getId() {
+        return ID;
+    }
+
+
+    @Override
+    public SynchronizationResult sync(KeycloakSessionFactory sessionFactory, String realmId,
+                                      UserStorageProviderModel model) {
+        // Manually Launch a synchronization between keycloack and the SCIM endpoint described in the given model
+        LOGGER.infof("[SCIM] Sync from ScimStorageProvider - Realm %s - Model %s", realmId, model.getName());
+        SynchronizationResult result = new SynchronizationResult();
+        KeycloakModelUtils.runJobInTransaction(sessionFactory, session -> {
+            RealmModel realm = session.realms().getRealm(realmId);
+            session.getContext().setRealm(realm);
+            ScimDispatcher dispatcher = new ScimDispatcher(session);
+            if (BooleanUtils.TRUE.equals(model.get(ScrimEndPointConfiguration.CONF_KEY_PROPAGATION_USER))) {
+                dispatcher.dispatchUserModificationToOne(model, client -> client.sync(result));
+            }
+            if (BooleanUtils.TRUE.equals(model.get(ScrimEndPointConfiguration.CONF_KEY_PROPAGATION_GROUP))) {
+                dispatcher.dispatchGroupModificationToOne(model, client -> client.sync(result));
+            }
+            dispatcher.close();
+        });
+        return result;
+    }
+
+    @Override
+    public SynchronizationResult syncSince(Date lastSync, KeycloakSessionFactory sessionFactory, String realmId,
+                                           UserStorageProviderModel model) {
+        return this.sync(sessionFactory, realmId, model);
+    }
+
+    @Override
+    public void postInit(KeycloakSessionFactory factory) {
+        ScimBackgroundGroupMembershipUpdater scimBackgroundGroupMembershipUpdater = new ScimBackgroundGroupMembershipUpdater(factory);
+        scimBackgroundGroupMembershipUpdater.startBackgroundUpdates();
+    }
+
+    @Override
+    public List<ProviderConfigProperty> getConfigProperties() {
+        // These Config Properties will be use to generate configuration page in Admin Console
+        return ProviderConfigurationBuilder.create()
+                .property()
+                .name(ScrimEndPointConfiguration.CONF_KEY_ENDPOINT)
+                .type(ProviderConfigProperty.STRING_TYPE)
+                .required(true)
+                .label("SCIM 2.0 endpoint")
+                .helpText("External SCIM 2.0 base " +
+                          "URL (/ServiceProviderConfig  /Schemas and /ResourcesTypes should be accessible)")
+                .add()
+                .property()
+                .name(ScrimEndPointConfiguration.CONF_KEY_CONTENT_TYPE)
+                .type(ProviderConfigProperty.LIST_TYPE)
+                .label("Endpoint content type")
+                .helpText("Only used when endpoint doesn't support application/scim+json")
+                .options(MediaType.APPLICATION_JSON, HttpHeader.SCIM_CONTENT_TYPE)
+                .defaultValue(HttpHeader.SCIM_CONTENT_TYPE)
+                .add()
+                .property()
+                .name(ScrimEndPointConfiguration.CONF_KEY_AUTH_MODE)
+                .type(ProviderConfigProperty.LIST_TYPE)
+                .label("Auth mode")
+                .helpText("Select the authorization mode")
+                .options("NONE", "BASIC_AUTH", "BEARER")
+                .defaultValue("NONE")
+                .add()
+                .property()
+                .name(ScrimEndPointConfiguration.CONF_KEY_AUTH_USER)
+                .type(ProviderConfigProperty.STRING_TYPE)
+                .label("Auth username")
+                .helpText("Required for basic authentication.")
+                .add()
+                .property()
+                .name(ScrimEndPointConfiguration.CONF_KEY_AUTH_PASSWORD)
+                .type(ProviderConfigProperty.PASSWORD)
+                .label("Auth password/token")
+                .helpText("Password or token required for basic or bearer authentication.")
+                .add()
+                .property()
+                .name(ScrimEndPointConfiguration.CONF_KEY_PROPAGATION_USER)
+                .type(ProviderConfigProperty.BOOLEAN_TYPE)
+                .label("Enable user propagation")
+                .helpText("Should operation on users be propagated to this provider?")
+                .defaultValue(BooleanUtils.TRUE)
+                .add()
+                .property()
+                .name(ScrimEndPointConfiguration.CONF_KEY_PROPAGATION_GROUP)
+                .type(ProviderConfigProperty.BOOLEAN_TYPE)
+                .label("Enable group propagation")
+                .helpText("Should operation on groups be propagated to this provider?")
+                .defaultValue(BooleanUtils.TRUE)
+                .add()
+                .property()
+                .name(ScrimEndPointConfiguration.CONF_KEY_SYNC_IMPORT)
+                .type(ProviderConfigProperty.BOOLEAN_TYPE)
+                .label("Enable import during sync")
+                .add()
+                .property()
+                .name(ScrimEndPointConfiguration.CONF_KEY_SYNC_IMPORT_ACTION)
+                .type(ProviderConfigProperty.LIST_TYPE)
+                .label("Import action")
+                .helpText("What to do when the user doesn't exists in Keycloak.")
+                .options("NOTHING", "CREATE_LOCAL", "DELETE_REMOTE")
+                .defaultValue("CREATE_LOCAL")
+                .add()
+                .property()
+                .name(ScrimEndPointConfiguration.CONF_KEY_SYNC_REFRESH)
+                .type(ProviderConfigProperty.BOOLEAN_TYPE)
+                .label("Enable refresh during sync")
+                .name(ScrimEndPointConfiguration.CONF_KEY_LOG_ALL_SCIM_REQUESTS)
+                .type(ProviderConfigProperty.BOOLEAN_TYPE)
+                .label("Log SCIM requests and responses")
+                .helpText("If true, all sent SCIM requests and responses will be logged")
+                .add()
+                .build();
+    }
+
+
+    @Override
+    public ScimEndpointConfigurationStorageProvider create(KeycloakSession session, ComponentModel model) {
+        return new ScimEndpointConfigurationStorageProvider();
+    }
+
+    /**
+     * Empty implementation : we used this {@link ScimEndpointConfigurationStorageProviderFactory} to generate Admin Console page.
+     */
+    public static final class ScimEndpointConfigurationStorageProvider implements UserStorageProvider {
+        @Override
+        public void close() {
+            // Nothing to close here
+        }
+    }
+}

federation/scim/src/main/java/sh/libre/scim/core/ScrimEndPointConfiguration.java

@@ -0,0 +1,101 @@
+package sh.libre.scim.core;
+
+import de.captaingoldfish.scim.sdk.client.http.BasicAuth;
+import org.keycloak.component.ComponentModel;
+
+public class ScrimEndPointConfiguration {
+    // Configuration keys : also used in Admin Console page
+    public static final String CONF_KEY_AUTH_MODE = "auth-mode";
+    public static final String CONF_KEY_AUTH_PASSWORD = "auth-pass";
+    public static final String CONF_KEY_AUTH_USER = "auth-user";
+    public static final String CONF_KEY_CONTENT_TYPE = "content-type";
+    public static final String CONF_KEY_ENDPOINT = "endpoint";
+    public static final String CONF_KEY_SYNC_IMPORT_ACTION = "sync-import-action";
+    public static final String CONF_KEY_SYNC_IMPORT = "sync-import";
+    public static final String CONF_KEY_SYNC_REFRESH = "sync-refresh";
+    public static final String CONF_KEY_PROPAGATION_USER = "propagation-user";
+    public static final String CONF_KEY_PROPAGATION_GROUP = "propagation-group";
+    public static final String CONF_KEY_LOG_ALL_SCIM_REQUESTS = "log-all-scim-requests";
+
+    private final String endPoint;
+    private final String id;
+    private final String name;
+    private final String contentType;
+    private final String authorizationHeaderValue;
+    private final ImportAction importAction;
+    private final boolean pullFromScimSynchronisationActivated;
+    private final boolean pushToScimSynchronisationActivated;
+    private final boolean logAllScimRequests;
+
+    public ScrimEndPointConfiguration(ComponentModel scimProviderConfiguration) {
+        try {
+            AuthMode authMode = AuthMode.valueOf(scimProviderConfiguration.get(CONF_KEY_AUTH_MODE));
+
+            authorizationHeaderValue = switch (authMode) {
+                case BEARER -> "Bearer " + scimProviderConfiguration.get(CONF_KEY_AUTH_PASSWORD);
+                case BASIC_AUTH -> {
+                    BasicAuth basicAuth = BasicAuth.builder()
+                            .username(scimProviderConfiguration.get(CONF_KEY_AUTH_USER))
+                            .password(scimProviderConfiguration.get(CONF_KEY_AUTH_PASSWORD))
+                            .build();
+                    yield basicAuth.getAuthorizationHeaderValue();
+                }
+                case NONE -> "";
+            };
+            contentType = scimProviderConfiguration.get(CONF_KEY_CONTENT_TYPE, "");
+            endPoint = scimProviderConfiguration.get(CONF_KEY_ENDPOINT, "");
+            id = scimProviderConfiguration.getId();
+            name = scimProviderConfiguration.getName();
+            importAction = ImportAction.valueOf(scimProviderConfiguration.get(CONF_KEY_SYNC_IMPORT_ACTION));
+            pullFromScimSynchronisationActivated = scimProviderConfiguration.get(CONF_KEY_SYNC_IMPORT, false);
+            pushToScimSynchronisationActivated = scimProviderConfiguration.get(CONF_KEY_SYNC_REFRESH, false);
+            logAllScimRequests = scimProviderConfiguration.get(CONF_KEY_LOG_ALL_SCIM_REQUESTS, false);
+        } catch (IllegalArgumentException e) {
+            throw new IllegalArgumentException("authMode '" + scimProviderConfiguration.get(CONF_KEY_AUTH_MODE) + "' is not supported");
+        }
+    }
+
+    public boolean isPushToScimSynchronisationActivated() {
+        return pushToScimSynchronisationActivated;
+    }
+
+    public boolean isPullFromScimSynchronisationActivated() {
+        return pullFromScimSynchronisationActivated;
+    }
+
+    public String getContentType() {
+        return contentType;
+    }
+
+    public String getAuthorizationHeaderValue() {
+        return authorizationHeaderValue;
+    }
+
+    public String getId() {
+        return id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public ImportAction getImportAction() {
+        return importAction;
+    }
+
+    public String getEndPoint() {
+        return endPoint;
+    }
+
+    public boolean isLogAllScimRequests() {
+        return logAllScimRequests;
+    }
+
+    public enum AuthMode {
+        BEARER, BASIC_AUTH, NONE
+    }
+
+    public enum ImportAction {
+        CREATE_LOCAL, DELETE_REMOTE, NOTHING
+    }
+}

federation/scim/src/main/java/sh/libre/scim/core/exceptions/InconsistentScimMappingException.java

@@ -0,0 +1,7 @@
+package sh.libre.scim.core.exceptions;
+
+public class InconsistentScimMappingException extends ScimPropagationException {
+    public InconsistentScimMappingException(String message) {
+        super(message);
+    }
+}

federation/scim/src/main/java/sh/libre/scim/core/exceptions/InvalidResponseFromScimEndpointException.java

@@ -0,0 +1,29 @@
+package sh.libre.scim.core.exceptions;
+
+import de.captaingoldfish.scim.sdk.client.response.ServerResponse;
+
+import java.util.Optional;
+
+public class InvalidResponseFromScimEndpointException extends ScimPropagationException {
+
+    private final transient Optional<ServerResponse> response;
+
+    public InvalidResponseFromScimEndpointException(ServerResponse response, String message) {
+        super(message);
+        this.response = Optional.of(response);
+    }
+
+    public InvalidResponseFromScimEndpointException(String message, Exception e) {
+        super(message, e);
+        this.response = Optional.empty();
+    }
+
+
+    /**
+     * Empty response can occur if a major exception was thrown while retrying the request.
+     */
+    public Optional<ServerResponse> getResponse() {
+        return response;
+    }
+
+}

federation/scim/src/main/java/sh/libre/scim/core/exceptions/RollbackApproach.java

@@ -0,0 +1,55 @@
+package sh.libre.scim.core.exceptions;
+
+import com.google.common.collect.Lists;
+import sh.libre.scim.core.ScrimEndPointConfiguration;
+
+import java.util.ArrayList;
+
+
+public enum RollbackApproach implements RollbackStrategy {
+    ALWAYS_ROLLBACK {
+        @Override
+        public boolean shouldRollback(ScrimEndPointConfiguration configuration, ScimPropagationException e) {
+            return true;
+        }
+    },
+    NEVER_ROLLBACK {
+        @Override
+        public boolean shouldRollback(ScrimEndPointConfiguration configuration, ScimPropagationException e) {
+            return false;
+        }
+    },
+    CRITICAL_ONLY_ROLLBACK {
+        @Override
+        public boolean shouldRollback(ScrimEndPointConfiguration configuration, ScimPropagationException e) {
+            if (e instanceof InconsistentScimMappingException) {
+                // Occurs when mapping between a SCIM resource and a keycloak user failed (missing, ambiguous..)
+                // Log can be sufficient here, no rollback required
+                return false;
+            }
+            if (e instanceof UnexpectedScimDataException) {
+                // Occurs when a SCIM endpoint sends invalid date (e.g. group with empty name, user without ids...)
+                // No rollback required : we cannot recover. This needs to be fixed in the SCIM endpoint data
+                return false;
+            }
+            if (e instanceof InvalidResponseFromScimEndpointException invalidResponseFromScimEndpointException) {
+                return shouldRollbackBecauseOfResponse(invalidResponseFromScimEndpointException);
+            }
+            // Should not occur
+            throw new IllegalStateException("Unkown ScimPropagationException", e);
+        }
+
+        private boolean shouldRollbackBecauseOfResponse(InvalidResponseFromScimEndpointException e) {
+            // If we have a response
+            return e.getResponse().map(r -> {
+                // We consider that 404 are acceptable, otherwise rollback
+                ArrayList<Integer> acceptableStatus = Lists.newArrayList(200, 204, 404);
+                return !acceptableStatus.contains(r.getHttpStatus());
+            }).orElse(
+                    // Never got an answer, server was either misconfigured or unreachable
+                    // No rollback in that case.
+                    false
+            );
+        }
+    }
+}

federation/scim/src/main/java/sh/libre/scim/core/exceptions/RollbackStrategy.java

@@ -0,0 +1,22 @@
+package sh.libre.scim.core.exceptions;
+
+import sh.libre.scim.core.ScrimEndPointConfiguration;
+
+/**
+ * In charge of deciding, when facing a SCIM-related issue during an operation (e.g User creation),
+ * whether we should :
+ * - Log the issue and let the operation succeed in Keycloack database (potentially unsynchronising
+ * Keycloack with the SCIM servers)
+ * - Rollback the whole operation
+ */
+public interface RollbackStrategy {
+
+    /**
+     * Indicates whether we should rollback the whole transaction because of the given exception.
+     *
+     * @param configuration The SCIM Endpoint configuration for which the exception occured
+     * @param e             the exception that we have to handle
+     * @return true if transaction should be rolled back, false if we should log and continue operation
+     */
+    boolean shouldRollback(ScrimEndPointConfiguration configuration, ScimPropagationException e);
+}

federation/scim/src/main/java/sh/libre/scim/core/exceptions/ScimExceptionHandler.java

@@ -0,0 +1,43 @@
+package sh.libre.scim.core.exceptions;
+
+import org.jboss.logging.Logger;
+import org.keycloak.models.KeycloakSession;
+import sh.libre.scim.core.ScrimEndPointConfiguration;
+
+/**
+ * In charge of dealing with SCIM exceptions by ignoring, logging or rollback transaction according to :
+ * - The context in which it occurs (sync, user creation...)
+ * - The related SCIM endpoint and its configuration
+ * - The thrown exception itself
+ */
+public class ScimExceptionHandler {
+    private static final Logger LOGGER = Logger.getLogger(ScimExceptionHandler.class);
+
+    private final KeycloakSession session;
+    private final RollbackStrategy rollbackStrategy;
+
+    public ScimExceptionHandler(KeycloakSession session) {
+        this(session, RollbackApproach.CRITICAL_ONLY_ROLLBACK);
+    }
+
+    public ScimExceptionHandler(KeycloakSession session, RollbackStrategy rollbackStrategy) {
+        this.session = session;
+        this.rollbackStrategy = rollbackStrategy;
+    }
+
+    /**
+     * Handles the given exception by loggin and/or rollback transaction.
+     *
+     * @param scimProviderConfiguration the configuration of the endpoint for which the propagation exception occured
+     * @param e                         the occuring exception
+     */
+    public void handleException(ScrimEndPointConfiguration scimProviderConfiguration, ScimPropagationException e) {
+        String errorMessage = "[SCIM] Error while propagating to SCIM endpoint " + scimProviderConfiguration.getName();
+        if (rollbackStrategy.shouldRollback(scimProviderConfiguration, e)) {
+            session.getTransactionManager().rollback();
+            LOGGER.error("TRANSACTION ROLLBACK - " + errorMessage, e);
+        } else {
+            LOGGER.warn(errorMessage, e);
+        }
+    }
+}

federation/scim/src/main/java/sh/libre/scim/core/exceptions/ScimPropagationException.java

@@ -0,0 +1,12 @@
+package sh.libre.scim.core.exceptions;
+
+public abstract class ScimPropagationException extends Exception {
+
+    protected ScimPropagationException(String message) {
+        super(message);
+    }
+
+    protected ScimPropagationException(String message, Exception e) {
+        super(message, e);
+    }
+}

federation/scim/src/main/java/sh/libre/scim/core/exceptions/SkipOrStopApproach.java

@@ -0,0 +1,59 @@
+package sh.libre.scim.core.exceptions;
+
+import sh.libre.scim.core.ScrimEndPointConfiguration;
+
+
+public enum SkipOrStopApproach implements SkipOrStopStrategy {
+    ALWAYS_SKIP_AND_CONTINUE {
+        @Override
+        public boolean allowPartialSynchronizationWhenPushingToScim(ScrimEndPointConfiguration configuration) {
+            return false;
+        }
+
+        @Override
+        public boolean allowPartialSynchronizationWhenPullingFromScim(ScrimEndPointConfiguration configuration) {
+            return false;
+        }
+
+        @Override
+        public boolean allowMissingMembersWhenPushingGroupToScim(ScrimEndPointConfiguration configuration) {
+            return false;
+        }
+
+        @Override
+        public boolean allowInvalidEndpointConfiguration() {
+            return false;
+        }
+
+        @Override
+        public boolean skipInvalidDataFromScimEndpoint(ScrimEndPointConfiguration configuration) {
+            return false;
+        }
+    },
+    ALWAYS_STOP {
+        @Override
+        public boolean allowPartialSynchronizationWhenPushingToScim(ScrimEndPointConfiguration configuration) {
+            return true;
+        }
+
+        @Override
+        public boolean allowPartialSynchronizationWhenPullingFromScim(ScrimEndPointConfiguration configuration) {
+            return true;
+        }
+
+        @Override
+        public boolean allowMissingMembersWhenPushingGroupToScim(ScrimEndPointConfiguration configuration) {
+            return true;
+        }
+
+        @Override
+        public boolean allowInvalidEndpointConfiguration() {
+            return true;
+        }
+
+        @Override
+        public boolean skipInvalidDataFromScimEndpoint(ScrimEndPointConfiguration configuration) {
+            return true;
+        }
+    }
+}

federation/scim/src/main/java/sh/libre/scim/core/exceptions/SkipOrStopStrategy.java

@@ -0,0 +1,66 @@
+package sh.libre.scim.core.exceptions;
+
+import sh.libre.scim.core.ScrimEndPointConfiguration;
+
+/**
+ * In charge of deciding, when facing a SCIM-related issue, whether we should :
+ * - log a warning, skip the problematic element and continue the rest of the operation
+ * - stop immediately the whole operation (typically, a synchronisation between SCIM and Keycloack)
+ */
+public interface SkipOrStopStrategy {
+    /**
+     * Indicates if,  during a synchronisation from Keycloack to a SCIM endpoint, we should :
+     * - cancel the whole synchronisation if an element CRUD fail, or
+     * - keep on with synchronisation, allowing a partial synchronisation
+     *
+     * @param configuration the configuration of the endpoint in which the error occurred
+     * @return true if a partial synchronisation is allowed,
+     * false if we should stop the whole synchronisation at first issue
+     */
+    boolean allowPartialSynchronizationWhenPushingToScim(ScrimEndPointConfiguration configuration);
+
+    /**
+     * Indicates if,  during a synchronisation from a SCIM endpoint to Keycloack, we should :
+     * - cancel the whole synchronisation if an element CRUD fail, or
+     * - keep on with synchronisation, allowing a partial synchronisation
+     *
+     * @param configuration the configuration of the endpoint in which the error occurred
+     * @return true if a partial synchronisation is allowed,
+     * false if we should interrupt the whole synchronisation at first issue
+     */
+    boolean allowPartialSynchronizationWhenPullingFromScim(ScrimEndPointConfiguration configuration);
+
+
+    /**
+     * Indicates if, when we propagate a group creation or update to a SCIM endpoint and some
+     * of its members are not mapped to SCIM, we should allow partial group update or interrupt completely.
+     *
+     * @param configuration the configuration of the endpoint in which the error occurred
+     * @return true if a partial group update is allowed,
+     * false if we should interrupt the group update in case of any unmapped member
+     */
+    boolean allowMissingMembersWhenPushingGroupToScim(ScrimEndPointConfiguration configuration);
+
+    /**
+     * Indicates if, when facing an invalid SCIM endpoint configuration (resulting in a unreachable SCIM server),
+     * we should stop or ignore this configuration.
+     *
+     * @return true the invalid endpoint should be ignored,
+     * * false if we should interrupt the rest of the synchronisation
+     */
+    boolean allowInvalidEndpointConfiguration();
+
+    /**
+     * Indicates if, when trying to pull User or Groups from a SCIM endpoint,
+     * we encounter a invalid data (e.g. group with empty name), we should :
+     * - Skip the invalid element pull and continue
+     * - Cancel the whole synchronisation
+     *
+     * @param configuration the configuration of the endpoint in which the error occurred
+     * @return true if we should skip the invalid data synchronisation and pursue,
+     * false if we should interrupt immediately the whole synchronisation
+     */
+    boolean skipInvalidDataFromScimEndpoint(ScrimEndPointConfiguration configuration);
+
+
+}

federation/scim/src/main/java/sh/libre/scim/core/exceptions/UnexpectedScimDataException.java

@@ -0,0 +1,7 @@
+package sh.libre.scim.core.exceptions;
+
+public class UnexpectedScimDataException extends ScimPropagationException {
+    public UnexpectedScimDataException(String message) {
+        super(message);
+    }
+}

federation/scim/src/main/java/sh/libre/scim/core/service/AbstractScimService.java

@@ -0,0 +1,281 @@
+package sh.libre.scim.core.service;
+
+import de.captaingoldfish.scim.sdk.common.resources.ResourceNode;
+import de.captaingoldfish.scim.sdk.common.resources.complex.Meta;
+import org.jboss.logging.Logger;
+import org.keycloak.models.KeycloakSession;
+import org.keycloak.models.RoleMapperModel;
+import org.keycloak.storage.user.SynchronizationResult;
+import sh.libre.scim.core.ScrimEndPointConfiguration;
+import sh.libre.scim.core.exceptions.InconsistentScimMappingException;
+import sh.libre.scim.core.exceptions.InvalidResponseFromScimEndpointException;
+import sh.libre.scim.core.exceptions.SkipOrStopStrategy;
+import sh.libre.scim.core.exceptions.UnexpectedScimDataException;
+import sh.libre.scim.jpa.ScimResourceDao;
+import sh.libre.scim.jpa.ScimResourceMapping;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.Optional;
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+/**
+ * A service in charge of synchronisation (CRUD) between
+ * a Keykloak Role (UserModel, GroupModel) and a SCIM Resource (User,Group).
+ *
+ * @param <K> The Keycloack Model (e.g. UserModel, GroupModel)
+ * @param <S> The SCIM Resource (e.g. User, Group)
+ */
+public abstract class AbstractScimService<K extends RoleMapperModel, S extends ResourceNode> implements AutoCloseable {
+
+    private static final Logger LOGGER = Logger.getLogger(AbstractScimService.class);
+
+    private final KeycloakSession keycloakSession;
+    protected final SkipOrStopStrategy skipOrStopStrategy;
+    private final ScrimEndPointConfiguration scimProviderConfiguration;
+    private final ScimResourceType type;
+    private final ScimClient<S> scimClient;
+
+    protected AbstractScimService(KeycloakSession keycloakSession, ScrimEndPointConfiguration scimProviderConfiguration, ScimResourceType type, SkipOrStopStrategy skipOrStopStrategy) {
+        this.keycloakSession = keycloakSession;
+        this.scimProviderConfiguration = scimProviderConfiguration;
+        this.type = type;
+        this.scimClient = ScimClient.open(scimProviderConfiguration, type);
+        this.skipOrStopStrategy = skipOrStopStrategy;
+    }
+
+    public void create(K roleMapperModel) throws InconsistentScimMappingException, InvalidResponseFromScimEndpointException {
+        if (isMarkedToIgnore(roleMapperModel)) {
+            // Silently return: resource is explicitly marked as to ignore
+            return;
+        }
+        // If mapping, then we are trying to recreate a user that was already created by import
+        KeycloakId id = getId(roleMapperModel);
+        if (findMappingById(id).isPresent()) {
+            throw new InconsistentScimMappingException("Trying to create user with id " + id + ": id already exists in Keycloak database");
+        }
+        S scimForCreation = scimRequestBodyForCreate(roleMapperModel);
+        EntityOnRemoteScimId externalId = scimClient.create(id, scimForCreation);
+        createMapping(id, externalId);
+    }
+
+    public void update(K roleMapperModel) throws InconsistentScimMappingException, InvalidResponseFromScimEndpointException {
+        if (isMarkedToIgnore(roleMapperModel)) {
+            // Silently return: resource is explicitly marked as to ignore
+            return;
+        }
+        KeycloakId keycloakId = getId(roleMapperModel);
+        EntityOnRemoteScimId entityOnRemoteScimId = findMappingById(keycloakId)
+                .map(ScimResourceMapping::getExternalIdAsEntityOnRemoteScimId)
+                .orElseThrow(() -> new InconsistentScimMappingException("Failed to find SCIM mapping for " + keycloakId));
+        S scimForReplace = scimRequestBodyForUpdate(roleMapperModel, entityOnRemoteScimId);
+        scimClient.update(entityOnRemoteScimId, scimForReplace);
+    }
+
+    protected abstract S scimRequestBodyForUpdate(K roleMapperModel, EntityOnRemoteScimId externalId) throws InconsistentScimMappingException;
+
+    public void delete(KeycloakId id) throws InconsistentScimMappingException, InvalidResponseFromScimEndpointException {
+        ScimResourceMapping resource = findMappingById(id)
+                .orElseThrow(() -> new InconsistentScimMappingException("Failed to delete resource %s, scim mapping not found: ".formatted(id)));
+        EntityOnRemoteScimId externalId = resource.getExternalIdAsEntityOnRemoteScimId();
+        scimClient.delete(externalId);
+        getScimResourceDao().delete(resource);
+    }
+
+    public void pushAllResourcesToScim(SynchronizationResult syncRes) throws InvalidResponseFromScimEndpointException, InconsistentScimMappingException {
+        LOGGER.info("[SCIM] Push resources to endpoint  " + this.getConfiguration().getEndPoint());
+        try (Stream<K> resourcesStream = getResourceStream()) {
+            Set<K> resources = resourcesStream.collect(Collectors.toUnmodifiableSet());
+            for (K resource : resources) {
+                KeycloakId id = getId(resource);
+                pushSingleResourceToScim(syncRes, resource, id);
+            }
+        }
+    }
+
+    public void pullAllResourcesFromScim(SynchronizationResult syncRes) throws UnexpectedScimDataException, InconsistentScimMappingException, InvalidResponseFromScimEndpointException {
+        LOGGER.info("[SCIM] Pull resources from endpoint " + this.getConfiguration().getEndPoint());
+        for (S resource : scimClient.listResources()) {
+            pullSingleResourceFromScim(syncRes, resource);
+        }
+    }
+
+    private void pushSingleResourceToScim(SynchronizationResult syncRes, K resource, KeycloakId id) throws InvalidResponseFromScimEndpointException, InconsistentScimMappingException {
+        try {
+            LOGGER.infof("[SCIM] Reconciling local resource %s", id);
+            if (shouldIgnoreForScimSynchronization(resource)) {
+                LOGGER.infof("[SCIM] Skip local resource %s", id);
+                return;
+            }
+            if (findMappingById(id).isPresent()) {
+                LOGGER.info("[SCIM] Replacing it");
+                update(resource);
+            } else {
+                LOGGER.info("[SCIM] Creating it");
+                create(resource);
+            }
+            syncRes.increaseUpdated();
+        } catch (InvalidResponseFromScimEndpointException e) {
+            if (skipOrStopStrategy.allowPartialSynchronizationWhenPushingToScim(this.getConfiguration())) {
+                LOGGER.warn("Error while syncing " + id + " to endpoint " + getConfiguration().getEndPoint(), e);
+            } else {
+                throw e;
+            }
+        } catch (InconsistentScimMappingException e) {
+            if (skipOrStopStrategy.allowPartialSynchronizationWhenPushingToScim(this.getConfiguration())) {
+                LOGGER.warn("Inconsistent data for element " + id + " and endpoint " + getConfiguration().getEndPoint(), e);
+            } else {
+                throw e;
+            }
+        }
+    }
+
+
+    private void pullSingleResourceFromScim(SynchronizationResult syncRes, S resource) throws UnexpectedScimDataException, InconsistentScimMappingException, InvalidResponseFromScimEndpointException {
+        try {
+            LOGGER.infof("[SCIM] Reconciling remote resource %s", resource);
+            EntityOnRemoteScimId externalId = resource.getId()
+                    .map(EntityOnRemoteScimId::new)
+                    .orElseThrow(() -> new UnexpectedScimDataException("Remote SCIM resource doesn't have an id, cannot import it in Keycloak"));
+            if (validMappingAlreadyExists(externalId)) return;
+
+            // Here no keycloak user/group matching the SCIM external id exists
+            // Try to match existing keycloak resource by properties (username, email, name)
+            Optional<KeycloakId> mapped = matchKeycloakMappingByScimProperties(resource);
+            if (mapped.isPresent()) {
+                // If found a mapped, update
+                LOGGER.info("[SCIM] Matched SCIM resource " + externalId + " from properties with keycloak entity " + mapped.get());
+                createMapping(mapped.get(), externalId);
+                syncRes.increaseUpdated();
+            } else {
+                // If not, create it locally or deleting it remotely (according to the configured Import Action)
+                createLocalOrDeleteRemote(syncRes, resource, externalId);
+            }
+        } catch (UnexpectedScimDataException e) {
+            if (skipOrStopStrategy.skipInvalidDataFromScimEndpoint(getConfiguration())) {
+                LOGGER.warn("[SCIM] Skipping element synchronisation because of invalid Scim Data for element " + resource.getId() + " : " + e.getMessage(), e);
+            } else {
+                throw e;
+            }
+        } catch (InconsistentScimMappingException e) {
+            if (skipOrStopStrategy.allowPartialSynchronizationWhenPullingFromScim(getConfiguration())) {
+                LOGGER.warn("[SCIM] Skipping element synchronisation because of inconsistent mapping for element " + resource.getId() + " : " + e.getMessage(), e);
+            } else {
+                throw e;
+            }
+        } catch (InvalidResponseFromScimEndpointException e) {
+            // Can only occur in case of a DELETE_REMOTE conflict action
+            if (skipOrStopStrategy.allowPartialSynchronizationWhenPullingFromScim(getConfiguration())) {
+                LOGGER.warn("[SCIM] Could not  delete SCIM resource " + resource.getId() + " during synchronisation", e);
+            } else {
+                throw e;
+            }
+        }
+
+    }
+
+    private boolean validMappingAlreadyExists(EntityOnRemoteScimId externalId) {
+        Optional<ScimResourceMapping> optionalMapping = getScimResourceDao().findByExternalId(externalId, type);
+        // If an existing mapping exists, delete potential dangling references
+        if (optionalMapping.isPresent()) {
+            ScimResourceMapping mapping = optionalMapping.get();
+            if (entityExists(mapping.getIdAsKeycloakId())) {
+                LOGGER.info("[SCIM] Valid mapping found, skipping");
+                return true;
+            } else {
+                LOGGER.info("[SCIM] Delete a dangling mapping");
+                getScimResourceDao().delete(mapping);
+            }
+        }
+        return false;
+    }
+
+    private void createLocalOrDeleteRemote(SynchronizationResult syncRes, S resource, EntityOnRemoteScimId externalId) throws UnexpectedScimDataException, InconsistentScimMappingException, InvalidResponseFromScimEndpointException {
+        switch (scimProviderConfiguration.getImportAction()) {
+            case CREATE_LOCAL -> {
+                LOGGER.info("[SCIM] Create local resource for SCIM resource " + externalId);
+                KeycloakId id = createEntity(resource);
+                createMapping(id, externalId);
+                syncRes.increaseAdded();
+            }
+            case DELETE_REMOTE -> {
+                LOGGER.info("[SCIM] Delete remote resource " + externalId);
+                scimClient.delete(externalId);
+            }
+            case NOTHING -> LOGGER.info("[SCIM] Import action set to NOTHING");
+        }
+    }
+
+
+    protected abstract S scimRequestBodyForCreate(K roleMapperModel) throws InconsistentScimMappingException;
+
+    protected abstract KeycloakId getId(K roleMapperModel);
+
+    protected abstract boolean isMarkedToIgnore(K roleMapperModel);
+
+    private void createMapping(KeycloakId keycloakId, EntityOnRemoteScimId externalId) {
+        getScimResourceDao().create(keycloakId, externalId, type);
+    }
+
+    protected ScimResourceDao getScimResourceDao() {
+        return ScimResourceDao.newInstance(getKeycloakSession(), scimProviderConfiguration.getId());
+    }
+
+    private Optional<ScimResourceMapping> findMappingById(KeycloakId keycloakId) {
+        return getScimResourceDao().findById(keycloakId, type);
+    }
+
+    private KeycloakSession getKeycloakSession() {
+        return keycloakSession;
+    }
+
+
+    protected abstract boolean shouldIgnoreForScimSynchronization(K resource);
+
+    protected abstract Stream<K> getResourceStream();
+
+    protected abstract KeycloakId createEntity(S resource) throws UnexpectedScimDataException, InconsistentScimMappingException;
+
+    protected abstract Optional<KeycloakId> matchKeycloakMappingByScimProperties(S resource) throws InconsistentScimMappingException;
+
+    protected abstract boolean entityExists(KeycloakId keycloakId);
+
+    public void sync(SynchronizationResult syncRes) throws InconsistentScimMappingException, InvalidResponseFromScimEndpointException, UnexpectedScimDataException {
+        if (this.scimProviderConfiguration.isPullFromScimSynchronisationActivated()) {
+            this.pullAllResourcesFromScim(syncRes);
+        }
+        if (this.scimProviderConfiguration.isPushToScimSynchronisationActivated()) {
+            this.pushAllResourcesToScim(syncRes);
+        }
+    }
+
+    protected Meta newMetaLocation(EntityOnRemoteScimId externalId) {
+        Meta meta = new Meta();
+        URI uri = getUri(type, externalId);
+        meta.setLocation(uri.toString());
+        return meta;
+    }
+
+    protected URI getUri(ScimResourceType type, EntityOnRemoteScimId externalId) {
+        try {
+            return new URI("%s/%s".formatted(type.getEndpoint(), externalId.asString()));
+        } catch (URISyntaxException e) {
+            throw new IllegalStateException("should never occur: can not format URI for type %s and id %s".formatted(type, externalId), e);
+        }
+    }
+
+    protected KeycloakDao getKeycloakDao() {
+        return new KeycloakDao(getKeycloakSession());
+    }
+
+    @Override
+    public void close() {
+        scimClient.close();
+    }
+
+    public ScrimEndPointConfiguration getConfiguration() {
+        return scimProviderConfiguration;
+    }
+}

federation/scim/src/main/java/sh/libre/scim/core/service/EntityOnRemoteScimId.java

@@ -0,0 +1,6 @@
+package sh.libre.scim.core.service;
+
+public record EntityOnRemoteScimId(
+        String asString
+) {
+}

federation/scim/src/main/java/sh/libre/scim/core/service/GroupScimService.java

@@ -0,0 +1,131 @@
+package sh.libre.scim.core.service;
+
+import de.captaingoldfish.scim.sdk.common.resources.Group;
+import de.captaingoldfish.scim.sdk.common.resources.complex.Meta;
+import de.captaingoldfish.scim.sdk.common.resources.multicomplex.Member;
+import org.apache.commons.collections4.CollectionUtils;
+import org.apache.commons.lang3.BooleanUtils;
+import org.apache.commons.lang3.StringUtils;
+import org.jboss.logging.Logger;
+import org.keycloak.models.GroupModel;
+import org.keycloak.models.KeycloakSession;
+import org.keycloak.models.UserModel;
+import sh.libre.scim.core.ScrimEndPointConfiguration;
+import sh.libre.scim.core.exceptions.InconsistentScimMappingException;
+import sh.libre.scim.core.exceptions.SkipOrStopStrategy;
+import sh.libre.scim.core.exceptions.UnexpectedScimDataException;
+import sh.libre.scim.jpa.ScimResourceMapping;
+
+import java.net.URI;
+import java.util.List;
+import java.util.Optional;
+import java.util.Set;
+import java.util.TreeSet;
+import java.util.stream.Stream;
+
+public class GroupScimService extends AbstractScimService<GroupModel, Group> {
+    private static final Logger LOGGER = Logger.getLogger(GroupScimService.class);
+
+    public GroupScimService(KeycloakSession keycloakSession, ScrimEndPointConfiguration scimProviderConfiguration, SkipOrStopStrategy skipOrStopStrategy) {
+        super(keycloakSession, scimProviderConfiguration, ScimResourceType.GROUP, skipOrStopStrategy);
+    }
+
+    @Override
+    protected Stream<GroupModel> getResourceStream() {
+        return getKeycloakDao().getGroupsStream();
+    }
+
+    @Override
+    protected boolean entityExists(KeycloakId keycloakId) {
+        return getKeycloakDao().groupExists(keycloakId);
+    }
+
+    @Override
+    protected Optional<KeycloakId> matchKeycloakMappingByScimProperties(Group resource) {
+        Set<String> names = new TreeSet<>();
+        resource.getId().ifPresent(names::add);
+        resource.getDisplayName().ifPresent(names::add);
+        try (Stream<GroupModel> groupsStream = getKeycloakDao().getGroupsStream()) {
+            Optional<GroupModel> group = groupsStream
+                    .filter(groupModel -> names.contains(groupModel.getName()))
+                    .findFirst();
+            return group
+                    .map(GroupModel::getId)
+                    .map(KeycloakId::new);
+        }
+    }
+
+    @Override
+    protected KeycloakId createEntity(Group resource) throws UnexpectedScimDataException, InconsistentScimMappingException {
+        String displayName = resource.getDisplayName()
+                .filter(StringUtils::isNotBlank)
+                .orElseThrow(() -> new UnexpectedScimDataException("Remote Scim group has empty name, can't create. Resource id = %s".formatted(resource.getId())));
+        GroupModel group = getKeycloakDao().createGroup(displayName);
+        List<Member> groupMembers = resource.getMembers();
+        if (CollectionUtils.isNotEmpty(groupMembers)) {
+            for (Member groupMember : groupMembers) {
+                EntityOnRemoteScimId externalId = groupMember.getValue()
+                        .map(EntityOnRemoteScimId::new)
+                        .orElseThrow(() -> new UnexpectedScimDataException("can't create group member for group '%s' without id: ".formatted(displayName) + resource));
+                KeycloakId userId = getScimResourceDao().findUserByExternalId(externalId)
+                        .map(ScimResourceMapping::getIdAsKeycloakId)
+                        .orElseThrow(() -> new InconsistentScimMappingException("can't find mapping for group member %s".formatted(externalId)));
+                UserModel userModel = getKeycloakDao().getUserById(userId);
+                userModel.joinGroup(group);
+            }
+        }
+        return new KeycloakId(group.getId());
+    }
+
+    @Override
+    protected boolean isMarkedToIgnore(GroupModel groupModel) {
+        return BooleanUtils.TRUE.equals(groupModel.getFirstAttribute("scim-skip"));
+    }
+
+    @Override
+    protected KeycloakId getId(GroupModel groupModel) {
+        return new KeycloakId(groupModel.getId());
+    }
+
+    @Override
+    protected Group scimRequestBodyForCreate(GroupModel groupModel) throws InconsistentScimMappingException {
+        Set<KeycloakId> members = getKeycloakDao().getGroupMembers(groupModel);
+        Group group = new Group();
+        group.setExternalId(groupModel.getId());
+        group.setDisplayName(groupModel.getName());
+        for (KeycloakId member : members) {
+            Member groupMember = new Member();
+            Optional<ScimResourceMapping> optionalGroupMemberMapping = getScimResourceDao().findUserById(member);
+            if (optionalGroupMemberMapping.isPresent()) {
+                ScimResourceMapping groupMemberMapping = optionalGroupMemberMapping.get();
+                EntityOnRemoteScimId externalIdAsEntityOnRemoteScimId = groupMemberMapping.getExternalIdAsEntityOnRemoteScimId();
+                groupMember.setValue(externalIdAsEntityOnRemoteScimId.asString());
+                URI ref = getUri(ScimResourceType.USER, externalIdAsEntityOnRemoteScimId);
+                groupMember.setRef(ref.toString());
+                group.addMember(groupMember);
+            } else {
+                String message = "Unmapped member " + member + " for group " + groupModel.getId();
+                if (skipOrStopStrategy.allowMissingMembersWhenPushingGroupToScim(this.getConfiguration())) {
+                    LOGGER.warn(message);
+                } else {
+                    throw new InconsistentScimMappingException(message);
+                }
+            }
+        }
+        return group;
+    }
+
+    @Override
+    protected Group scimRequestBodyForUpdate(GroupModel groupModel, EntityOnRemoteScimId externalId) throws InconsistentScimMappingException {
+        Group group = scimRequestBodyForCreate(groupModel);
+        group.setId(externalId.asString());
+        Meta meta = newMetaLocation(externalId);
+        group.setMeta(meta);
+        return group;
+    }
+
+    @Override
+    protected boolean shouldIgnoreForScimSynchronization(GroupModel resource) {
+        return false;
+    }
+}

federation/scim/src/main/java/sh/libre/scim/core/service/KeycloakDao.java

@@ -0,0 +1,81 @@
+package sh.libre.scim.core.service;
+
+import org.keycloak.models.GroupModel;
+import org.keycloak.models.KeycloakSession;
+import org.keycloak.models.RealmModel;
+import org.keycloak.models.UserModel;
+
+import java.util.Collections;
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+public class KeycloakDao {
+
+    private final KeycloakSession keycloakSession;
+
+    public KeycloakDao(KeycloakSession keycloakSession) {
+        this.keycloakSession = keycloakSession;
+    }
+
+    private KeycloakSession getKeycloakSession() {
+        return keycloakSession;
+    }
+
+    private RealmModel getRealm() {
+        return getKeycloakSession().getContext().getRealm();
+    }
+
+    public boolean groupExists(KeycloakId groupId) {
+        GroupModel group = getKeycloakSession().groups().getGroupById(getRealm(), groupId.asString());
+        return group != null;
+    }
+
+    public boolean userExists(KeycloakId userId) {
+        UserModel user = getUserById(userId);
+        return user != null;
+    }
+
+    public UserModel getUserById(KeycloakId userId) {
+        return getKeycloakSession().users().getUserById(getRealm(), userId.asString());
+    }
+
+    public GroupModel getGroupById(KeycloakId groupId) {
+        return getKeycloakSession().groups().getGroupById(getRealm(), groupId.asString());
+    }
+
+
+    public Stream<GroupModel> getGroupsStream() {
+        return getKeycloakSession().groups().getGroupsStream(getRealm());
+    }
+
+    public GroupModel createGroup(String displayName) {
+        return getKeycloakSession().groups().createGroup(getRealm(), displayName);
+    }
+
+    public Set<KeycloakId> getGroupMembers(GroupModel groupModel) {
+        return getKeycloakSession().users()
+                .getGroupMembersStream(getRealm(), groupModel)
+                .map(UserModel::getId)
+                .map(KeycloakId::new)
+                .collect(Collectors.toSet());
+    }
+
+    public Stream<UserModel> getUsersStream() {
+        return getKeycloakSession().users().searchForUserStream(getRealm(), Collections.emptyMap());
+    }
+
+    public UserModel getUserByUsername(String username) {
+        return getKeycloakSession().users().getUserByUsername(getRealm(), username);
+    }
+
+    public UserModel getUserByEmail(String email) {
+        return getKeycloakSession().users().getUserByEmail(getRealm(), email);
+    }
+
+    public UserModel addUser(String username) {
+        return getKeycloakSession().users().addUser(getRealm(), username);
+    }
+
+
+}

federation/scim/src/main/java/sh/libre/scim/core/service/KeycloakId.java

@@ -0,0 +1,7 @@
+package sh.libre.scim.core.service;
+
+public record KeycloakId(
+        String asString
+) {
+
+}

federation/scim/src/main/java/sh/libre/scim/core/service/ScimClient.java

@@ -0,0 +1,155 @@
+package sh.libre.scim.core.service;
+
+import com.google.common.net.HttpHeaders;
+import de.captaingoldfish.scim.sdk.client.ScimClientConfig;
+import de.captaingoldfish.scim.sdk.client.ScimRequestBuilder;
+import de.captaingoldfish.scim.sdk.client.response.ServerResponse;
+import de.captaingoldfish.scim.sdk.common.resources.ResourceNode;
+import de.captaingoldfish.scim.sdk.common.response.ListResponse;
+import io.github.resilience4j.core.IntervalFunction;
+import io.github.resilience4j.retry.Retry;
+import io.github.resilience4j.retry.RetryConfig;
+import io.github.resilience4j.retry.RetryRegistry;
+import jakarta.ws.rs.ProcessingException;
+import org.jboss.logging.Logger;
+import sh.libre.scim.core.ScrimEndPointConfiguration;
+import sh.libre.scim.core.exceptions.InvalidResponseFromScimEndpointException;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+
+public class ScimClient<S extends ResourceNode> implements AutoCloseable {
+    private static final Logger LOGGER = Logger.getLogger(ScimClient.class);
+
+    private final RetryRegistry retryRegistry;
+
+    private final ScimRequestBuilder scimRequestBuilder;
+
+    private final ScimResourceType scimResourceType;
+    private final boolean logAllRequests;
+
+    private ScimClient(ScimRequestBuilder scimRequestBuilder, ScimResourceType scimResourceType, boolean detailedLogs) {
+        this.scimRequestBuilder = scimRequestBuilder;
+        this.scimResourceType = scimResourceType;
+        RetryConfig retryConfig = RetryConfig.custom()
+                .maxAttempts(10)
+                .intervalFunction(IntervalFunction.ofExponentialBackoff())
+                .retryExceptions(ProcessingException.class)
+                .build();
+        retryRegistry = RetryRegistry.of(retryConfig);
+        this.logAllRequests = detailedLogs;
+    }
+
+    public static <T extends ResourceNode> ScimClient<T> open(ScrimEndPointConfiguration scimProviderConfiguration, ScimResourceType scimResourceType) {
+        String scimApplicationBaseUrl = scimProviderConfiguration.getEndPoint();
+        Map<String, String> httpHeaders = new HashMap<>();
+        httpHeaders.put(HttpHeaders.AUTHORIZATION, scimProviderConfiguration.getAuthorizationHeaderValue());
+        httpHeaders.put(HttpHeaders.CONTENT_TYPE, scimProviderConfiguration.getContentType());
+        ScimClientConfig scimClientConfig = ScimClientConfig.builder()
+                .httpHeaders(httpHeaders)
+                .connectTimeout(5)
+                .requestTimeout(5)
+                .socketTimeout(5)
+                .build();
+        ScimRequestBuilder scimRequestBuilder =
+                new ScimRequestBuilder(
+                        scimApplicationBaseUrl,
+                        scimClientConfig
+                );
+        return new ScimClient<>(scimRequestBuilder, scimResourceType, scimProviderConfiguration.isLogAllScimRequests());
+    }
+
+    public EntityOnRemoteScimId create(KeycloakId id, S scimForCreation) throws InvalidResponseFromScimEndpointException {
+        Optional<String> scimForCreationId = scimForCreation.getId();
+        if (scimForCreationId.isPresent()) {
+            throw new IllegalArgumentException(
+                    "User to create should never have an existing id: %s %s".formatted(id, scimForCreationId.get())
+            );
+        }
+        try {
+            Retry retry = retryRegistry.retry("create-%s".formatted(id.asString()));
+            if (logAllRequests) {
+                LOGGER.info("[SCIM] Sending CREATE " + scimForCreation.toPrettyString() + "\n to " + getScimEndpoint());
+            }
+            ServerResponse<S> response = retry.executeSupplier(() -> scimRequestBuilder
+                    .create(getResourceClass(), getScimEndpoint())
+                    .setResource(scimForCreation)
+                    .sendRequest()
+            );
+            checkResponseIsSuccess(response);
+            S resource = response.getResource();
+            return resource.getId()
+                    .map(EntityOnRemoteScimId::new)
+                    .orElseThrow(() -> new InvalidResponseFromScimEndpointException(response, "Created SCIM resource does not have id"));
+
+        } catch (Exception e) {
+            LOGGER.warn(e);
+            throw new InvalidResponseFromScimEndpointException("Exception while retrying create " + e.getMessage(), e);
+        }
+    }
+
+    private void checkResponseIsSuccess(ServerResponse<S> response) throws InvalidResponseFromScimEndpointException {
+        if (logAllRequests) {
+            LOGGER.info("[SCIM] Server response " + response.getHttpStatus() + "\n" + response.getResponseBody());
+        }
+        if (!response.isSuccess()) {
+            throw new InvalidResponseFromScimEndpointException(response, "Server answered with status " + response.getResponseBody() + ": " + response.getResponseBody());
+        }
+    }
+
+    private String getScimEndpoint() {
+        return scimResourceType.getEndpoint();
+    }
+
+    private Class<S> getResourceClass() {
+        return scimResourceType.getResourceClass();
+    }
+
+    public void update(EntityOnRemoteScimId externalId, S scimForReplace) throws InvalidResponseFromScimEndpointException {
+        Retry retry = retryRegistry.retry("replace-%s".formatted(externalId.asString()));
+        try {
+            if (logAllRequests) {
+                LOGGER.info("[SCIM] Sending UPDATE " + scimForReplace.toPrettyString() + "\n to " + getScimEndpoint());
+            }
+            ServerResponse<S> response = retry.executeSupplier(() -> scimRequestBuilder
+                    .update(getResourceClass(), getScimEndpoint(), externalId.asString())
+                    .setResource(scimForReplace)
+                    .sendRequest()
+            );
+            checkResponseIsSuccess(response);
+        } catch (Exception e) {
+            LOGGER.warn(e);
+            throw new InvalidResponseFromScimEndpointException("Exception while retrying update " + e.getMessage(), e);
+        }
+    }
+
+    public void delete(EntityOnRemoteScimId externalId) throws InvalidResponseFromScimEndpointException {
+        Retry retry = retryRegistry.retry("delete-%s".formatted(externalId.asString()));
+        if (logAllRequests) {
+            LOGGER.info("[SCIM] Sending DELETE to " + getScimEndpoint());
+        }
+        try {
+            ServerResponse<S> response = retry.executeSupplier(() -> scimRequestBuilder
+                    .delete(getResourceClass(), getScimEndpoint(), externalId.asString())
+                    .sendRequest()
+            );
+            checkResponseIsSuccess(response);
+        } catch (Exception e) {
+            LOGGER.warn(e);
+            throw new InvalidResponseFromScimEndpointException("Exception while retrying delete " + e.getMessage(), e);
+        }
+    }
+
+    @Override
+    public void close() {
+        scimRequestBuilder.close();
+    }
+
+    public List<S> listResources() {
+        ServerResponse<ListResponse<S>> response = scimRequestBuilder.list(getResourceClass(), getScimEndpoint()).get().sendRequest();
+        ListResponse<S> resourceTypeListResponse = response.getResource();
+        return resourceTypeListResponse.getListedResources();
+    }
+}

federation/scim/src/main/java/sh/libre/scim/core/service/ScimResourceType.java

@@ -0,0 +1,29 @@
+package sh.libre.scim.core.service;
+
+import de.captaingoldfish.scim.sdk.common.resources.Group;
+import de.captaingoldfish.scim.sdk.common.resources.ResourceNode;
+import de.captaingoldfish.scim.sdk.common.resources.User;
+
+public enum ScimResourceType {
+
+    USER("/Users", User.class),
+
+    GROUP("/Groups", Group.class);
+
+    private final String endpoint;
+
+    private final Class<? extends ResourceNode> resourceClass;
+
+    ScimResourceType(String endpoint, Class<? extends ResourceNode> resourceClass) {
+        this.endpoint = endpoint;
+        this.resourceClass = resourceClass;
+    }
+
+    public String getEndpoint() {
+        return endpoint;
+    }
+
+    public <T extends ResourceNode> Class<T> getResourceClass() {
+        return (Class<T>) resourceClass;
+    }
+}

federation/scim/src/main/java/sh/libre/scim/core/service/UserScimService.java

@@ -0,0 +1,145 @@
+package sh.libre.scim.core.service;
+
+import de.captaingoldfish.scim.sdk.common.resources.User;
+import de.captaingoldfish.scim.sdk.common.resources.complex.Meta;
+import de.captaingoldfish.scim.sdk.common.resources.complex.Name;
+import de.captaingoldfish.scim.sdk.common.resources.multicomplex.Email;
+import de.captaingoldfish.scim.sdk.common.resources.multicomplex.MultiComplexNode;
+import de.captaingoldfish.scim.sdk.common.resources.multicomplex.PersonRole;
+import org.apache.commons.lang3.BooleanUtils;
+import org.apache.commons.lang3.StringUtils;
+import org.jboss.logging.Logger;
+import org.keycloak.models.KeycloakSession;
+import org.keycloak.models.RoleMapperModel;
+import org.keycloak.models.RoleModel;
+import org.keycloak.models.UserModel;
+import sh.libre.scim.core.ScrimEndPointConfiguration;
+import sh.libre.scim.core.exceptions.InconsistentScimMappingException;
+import sh.libre.scim.core.exceptions.SkipOrStopStrategy;
+import sh.libre.scim.core.exceptions.UnexpectedScimDataException;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.stream.Stream;
+
+public class UserScimService extends AbstractScimService<UserModel, User> {
+    private static final Logger LOGGER = Logger.getLogger(UserScimService.class);
+
+    public UserScimService(
+            KeycloakSession keycloakSession,
+            ScrimEndPointConfiguration scimProviderConfiguration,
+            SkipOrStopStrategy skipOrStopStrategy) {
+        super(keycloakSession, scimProviderConfiguration, ScimResourceType.USER, skipOrStopStrategy);
+    }
+
+    @Override
+    protected Stream<UserModel> getResourceStream() {
+        return getKeycloakDao().getUsersStream();
+    }
+
+    @Override
+    protected boolean entityExists(KeycloakId keycloakId) {
+        return getKeycloakDao().userExists(keycloakId);
+    }
+
+    @Override
+    protected Optional<KeycloakId> matchKeycloakMappingByScimProperties(User resource) throws InconsistentScimMappingException {
+        Optional<KeycloakId> matchedByUsername = resource.getUserName()
+                .map(getKeycloakDao()::getUserByUsername)
+                .map(this::getId);
+        Optional<KeycloakId> matchedByEmail = resource.getEmails().stream()
+                .findFirst()
+                .flatMap(MultiComplexNode::getValue)
+                .map(getKeycloakDao()::getUserByEmail)
+                .map(this::getId);
+        if (matchedByUsername.isPresent()
+            && matchedByEmail.isPresent()
+            && !matchedByUsername.equals(matchedByEmail)) {
+            String inconstencyErrorMessage = "Found 2 possible users for remote user " + matchedByUsername.get() + " - " + matchedByEmail.get();
+            LOGGER.warn(inconstencyErrorMessage);
+            throw new InconsistentScimMappingException(inconstencyErrorMessage);
+        }
+        if (matchedByUsername.isPresent()) {
+            return matchedByUsername;
+        }
+        return matchedByEmail;
+    }
+
+    @Override
+    protected KeycloakId createEntity(User resource) throws UnexpectedScimDataException {
+        String username = resource.getUserName()
+                .filter(StringUtils::isNotBlank)
+                .orElseThrow(() -> new UnexpectedScimDataException("Remote Scim user has empty username, can't create. Resource id = %s".formatted(resource.getId())));
+        UserModel user = getKeycloakDao().addUser(username);
+        resource.getEmails().stream()
+                .findFirst()
+                .flatMap(MultiComplexNode::getValue)
+                .ifPresent(user::setEmail);
+        boolean userEnabled = resource.isActive().orElse(false);
+        user.setEnabled(userEnabled);
+        return new KeycloakId(user.getId());
+    }
+
+    @Override
+    protected boolean isMarkedToIgnore(UserModel userModel) {
+        return BooleanUtils.TRUE.equals(userModel.getFirstAttribute("scim-skip"));
+    }
+
+    @Override
+    protected KeycloakId getId(UserModel userModel) {
+        return new KeycloakId(userModel.getId());
+    }
+
+    @Override
+    protected User scimRequestBodyForCreate(UserModel roleMapperModel) {
+        String firstAndLastName = String.format("%s %s",
+                StringUtils.defaultString(roleMapperModel.getFirstName()),
+                StringUtils.defaultString(roleMapperModel.getLastName())).trim();
+        String displayName = Objects.toString(firstAndLastName, roleMapperModel.getUsername());
+        Stream<RoleModel> groupRoleModels = roleMapperModel.getGroupsStream().flatMap(RoleMapperModel::getRoleMappingsStream);
+        Stream<RoleModel> roleModels = roleMapperModel.getRoleMappingsStream();
+        Stream<RoleModel> allRoleModels = Stream.concat(groupRoleModels, roleModels);
+        List<PersonRole> roles = allRoleModels
+                .filter(r -> BooleanUtils.TRUE.equals(r.getFirstAttribute("scim")))
+                .map(RoleModel::getName)
+                .map(roleName -> {
+                    PersonRole personRole = new PersonRole();
+                    personRole.setValue(roleName);
+                    return personRole;
+                })
+                .toList();
+        User user = new User();
+        user.setRoles(roles);
+        user.setExternalId(roleMapperModel.getId());
+        user.setUserName(roleMapperModel.getUsername());
+        user.setDisplayName(displayName);
+        Name name = new Name();
+        name.setFamilyName(roleMapperModel.getLastName());
+        name.setGivenName(roleMapperModel.getFirstName());
+        user.setName(name);
+        List<Email> emails = new ArrayList<>();
+        if (roleMapperModel.getEmail() != null) {
+            emails.add(
+                    Email.builder().value(roleMapperModel.getEmail()).build());
+        }
+        user.setEmails(emails);
+        user.setActive(roleMapperModel.isEnabled());
+        return user;
+    }
+
+    @Override
+    protected User scimRequestBodyForUpdate(UserModel userModel, EntityOnRemoteScimId externalId) {
+        User user = scimRequestBodyForCreate(userModel);
+        user.setId(externalId.asString());
+        Meta meta = newMetaLocation(externalId);
+        user.setMeta(meta);
+        return user;
+    }
+
+    @Override
+    protected boolean shouldIgnoreForScimSynchronization(UserModel userModel) {
+        return "admin".equals(userModel.getUsername());
+    }
+}

federation/scim/src/main/java/sh/libre/scim/event/ScimBackgroundGroupMembershipUpdater.java

@@ -0,0 +1,74 @@
+package sh.libre.scim.event;
+
+import org.jboss.logging.Logger;
+import org.keycloak.models.GroupModel;
+import org.keycloak.models.KeycloakSession;
+import org.keycloak.models.KeycloakSessionFactory;
+import org.keycloak.models.RealmModel;
+import org.keycloak.models.utils.KeycloakModelUtils;
+import org.keycloak.timer.TimerProvider;
+import sh.libre.scim.core.ScimDispatcher;
+
+import java.time.Duration;
+
+/**
+ * In charge of making background checks and sent
+ * UPDATE requests from group for which membership information has changed.
+ * <p>
+ * This is required to avoid immediate group membership updates which could cause
+ * to incorrect group members list in case of concurrent group membership changes.
+ */
+public class ScimBackgroundGroupMembershipUpdater {
+    public static final String GROUP_DIRTY_SINCE_ATTRIBUTE_NAME = "scim-dirty-since";
+
+    private static final Logger LOGGER = Logger.getLogger(ScimBackgroundGroupMembershipUpdater.class);
+    // Update check loop will run every time this delay has passed
+    private static final long UPDATE_CHECK_DELAY_MS = 2000;
+    // If a group is marked dirty since less that this debounce delay, wait for the next update check loop
+    private static final long DEBOUNCE_DELAY_MS = 1200;
+    private final KeycloakSessionFactory sessionFactory;
+
+    public ScimBackgroundGroupMembershipUpdater(KeycloakSessionFactory sessionFactory) {
+        this.sessionFactory = sessionFactory;
+    }
+
+    public void startBackgroundUpdates() {
+        // Every UPDATE_CHECK_DELAY_MS, check for dirty groups and send updates if required
+        try (KeycloakSession keycloakSession = sessionFactory.create()) {
+            TimerProvider timer = keycloakSession.getProvider(TimerProvider.class);
+            timer.scheduleTask(taskSession -> {
+                for (RealmModel realm : taskSession.realms().getRealmsStream().toList()) {
+                    dispatchDirtyGroupsUpdates(realm);
+                }
+            }, Duration.ofMillis(UPDATE_CHECK_DELAY_MS).toMillis(), "scim-background");
+        }
+    }
+
+    private void dispatchDirtyGroupsUpdates(RealmModel realm) {
+        KeycloakModelUtils.runJobInTransaction(sessionFactory, session -> {
+            session.getContext().setRealm(realm);
+            ScimDispatcher dispatcher = new ScimDispatcher(session);
+            // Identify groups marked as dirty by the ScimEventListenerProvider
+            for (GroupModel group : session.groups().getGroupsStream(realm)
+                    .filter(this::isDirtyGroup).toList()) {
+                LOGGER.infof("[SCIM] Group %s is dirty, dispatch an update", group.getName());
+                // If dirty : dispatch a group update to all clients and mark it clean
+                dispatcher.dispatchGroupModificationToAll(client -> client.update(group));
+                group.removeAttribute(GROUP_DIRTY_SINCE_ATTRIBUTE_NAME);
+            }
+            dispatcher.close();
+        });
+    }
+
+    private boolean isDirtyGroup(GroupModel g) {
+        String groupDirtySinceAttribute = g.getFirstAttribute(GROUP_DIRTY_SINCE_ATTRIBUTE_NAME);
+        try {
+            long groupDirtySince = Long.parseLong(groupDirtySinceAttribute);
+            // Must be dirty for more than DEBOUNCE_DELAY_MS
+            // (otherwise update will be dispatched in next scheduled loop)
+            return System.currentTimeMillis() - groupDirtySince > DEBOUNCE_DELAY_MS;
+        } catch (NumberFormatException e) {
+            return false;
+        }
+    }
+}

federation/scim/src/main/java/sh/libre/scim/event/ScimEventListenerProvider.java

@@ -0,0 +1,252 @@
+package sh.libre.scim.event;
+
+import org.jboss.logging.Logger;
+import org.keycloak.common.Profile;
+import org.keycloak.component.ComponentModel;
+import org.keycloak.events.Event;
+import org.keycloak.events.EventListenerProvider;
+import org.keycloak.events.EventType;
+import org.keycloak.events.admin.AdminEvent;
+import org.keycloak.events.admin.OperationType;
+import org.keycloak.events.admin.ResourceType;
+import org.keycloak.models.GroupModel;
+import org.keycloak.models.KeycloakSession;
+import org.keycloak.models.UserModel;
+import sh.libre.scim.core.ScimDispatcher;
+import sh.libre.scim.core.ScimEndpointConfigurationStorageProviderFactory;
+import sh.libre.scim.core.service.KeycloakDao;
+import sh.libre.scim.core.service.KeycloakId;
+import sh.libre.scim.core.service.ScimResourceType;
+
+import java.util.Map;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import java.util.stream.Stream;
+
+/**
+ * An Event listener reacting to Keycloak models  modification
+ * (e.g. User creation, Group deletion, membership modifications, endpoint configuration change...)
+ * by propagating it to all registered Scim endpoints.
+ */
+public class ScimEventListenerProvider implements EventListenerProvider {
+
+    private static final Logger LOGGER = Logger.getLogger(ScimEventListenerProvider.class);
+
+    private final ScimDispatcher dispatcher;
+
+    private final KeycloakSession session;
+
+    private final KeycloakDao keycloakDao;
+
+    private final Map<ResourceType, Pattern> listenedEventPathPatterns = Map.of(
+            ResourceType.USER, Pattern.compile("users/(.+)"),
+            ResourceType.GROUP, Pattern.compile("groups/([\\w-]+)(/children)?"),
+            ResourceType.GROUP_MEMBERSHIP, Pattern.compile("users/(.+)/groups/(.+)"),
+            ResourceType.REALM_ROLE_MAPPING, Pattern.compile("^(.+)/(.+)/role-mappings"),
+            ResourceType.COMPONENT, Pattern.compile("components/(.+)")
+    );
+
+    public ScimEventListenerProvider(KeycloakSession session) {
+        this.session = session;
+        this.keycloakDao = new KeycloakDao(session);
+        this.dispatcher = new ScimDispatcher(session);
+    }
+
+    @Override
+    public void onEvent(Event event) {
+        if (!Profile.isFeatureEnabled(Profile.Feature.SCIM)) {
+            // React to User-related event : creation, deletion, update
+            EventType eventType = event.getType();
+            KeycloakId eventUserId = new KeycloakId(event.getUserId());
+            switch (eventType) {
+                case REGISTER -> {
+                    LOGGER.infof("[SCIM] Propagate User Registration - %s", eventUserId);
+                    UserModel user = getUser(eventUserId);
+                    dispatcher.dispatchUserModificationToAll(client -> client.create(user));
+                }
+                case UPDATE_EMAIL, UPDATE_PROFILE -> {
+                    LOGGER.infof("[SCIM] Propagate User %s - %s", eventType, eventUserId);
+                    UserModel user = getUser(eventUserId);
+                    dispatcher.dispatchUserModificationToAll(client -> client.update(user));
+                }
+                case DELETE_ACCOUNT -> {
+                    LOGGER.infof("[SCIM] Propagate User deletion - %s", eventUserId);
+                    dispatcher.dispatchUserModificationToAll(client -> client.delete(eventUserId));
+                }
+                default -> {
+                    // No other event has to be propagated to Scim endpoints
+                }
+            }
+        }
+    }
+
+
+    @Override
+    public void onEvent(AdminEvent event, boolean includeRepresentation) {
+        if (!Profile.isFeatureEnabled(Profile.Feature.SCIM)) {
+            // Step 1: check if event is relevant for propagation through SCIM
+            Pattern pattern = listenedEventPathPatterns.get(event.getResourceType());
+            if (pattern == null)
+                return;
+            Matcher matcher = pattern.matcher(event.getResourcePath());
+            if (!matcher.find())
+                return;
+
+
+            // Step 2: propagate event (if needed) according to its resource type
+            switch (event.getResourceType()) {
+                case USER -> {
+                    KeycloakId userId = new KeycloakId(matcher.group(1));
+                    handleUserEvent(event, userId);
+                }
+                case GROUP -> {
+                    KeycloakId groupId = new KeycloakId(matcher.group(1));
+                    handleGroupEvent(event, groupId);
+                }
+                case GROUP_MEMBERSHIP -> {
+                    KeycloakId userId = new KeycloakId(matcher.group(1));
+                    KeycloakId groupId = new KeycloakId(matcher.group(2));
+                    handleGroupMemberShipEvent(event, userId, groupId);
+                }
+                case REALM_ROLE_MAPPING -> {
+                    String rawResourceType = matcher.group(1);
+                    ScimResourceType type = switch (rawResourceType) {
+                        case "users" -> ScimResourceType.USER;
+                        case "groups" -> ScimResourceType.GROUP;
+                        default -> throw new IllegalArgumentException("Unsupported resource type: " + rawResourceType);
+                    };
+                    KeycloakId id = new KeycloakId(matcher.group(2));
+                    handleRoleMappingEvent(event, type, id);
+                }
+                case COMPONENT -> {
+                    String id = matcher.group(1);
+                    handleScimEndpointConfigurationEvent(event, id);
+
+                }
+                default -> {
+                    // No other resource modification has to be propagated to Scim endpoints
+                }
+            }
+        }
+    }
+
+
+    private void handleUserEvent(AdminEvent userEvent, KeycloakId userId) {
+        LOGGER.infof("[SCIM] Propagate User %s - %s", userEvent.getOperationType(), userId);
+        switch (userEvent.getOperationType()) {
+            case CREATE -> {
+                UserModel user = getUser(userId);
+                dispatcher.dispatchUserModificationToAll(client -> client.create(user));
+                user.getGroupsStream().forEach(group ->
+                        dispatcher.dispatchGroupModificationToAll(client -> client.update(group)
+                        ));
+            }
+            case UPDATE -> {
+                UserModel user = getUser(userId);
+                dispatcher.dispatchUserModificationToAll(client -> client.update(user));
+            }
+            case DELETE -> dispatcher.dispatchUserModificationToAll(client -> client.delete(userId));
+            default -> {
+                // ACTION userEvent are not relevant, nothing to do
+            }
+        }
+    }
+
+    /**
+     * Propagating the given group-related event to Scim endpoints.
+     *
+     * @param event   the event to propagate
+     * @param groupId event target's id
+     */
+    private void handleGroupEvent(AdminEvent event, KeycloakId groupId) {
+        LOGGER.infof("[SCIM] Propagate Group %s - %s", event.getOperationType(), groupId);
+        switch (event.getOperationType()) {
+            case CREATE -> {
+                GroupModel group = getGroup(groupId);
+                dispatcher.dispatchGroupModificationToAll(client -> client.create(group));
+            }
+            case UPDATE -> {
+                GroupModel group = getGroup(groupId);
+                dispatcher.dispatchGroupModificationToAll(client -> client.update(group));
+            }
+            case DELETE -> dispatcher.dispatchGroupModificationToAll(client -> client.delete(groupId));
+            default -> {
+                // ACTION event are not relevant, nothing to do
+            }
+        }
+    }
+
+    private void handleGroupMemberShipEvent(AdminEvent groupMemberShipEvent, KeycloakId userId, KeycloakId groupId) {
+        LOGGER.infof("[SCIM] Propagate GroupMemberShip %s - User %s Group %s", groupMemberShipEvent.getOperationType(), userId, groupId);
+        // Step 1: update USER immediately
+        GroupModel group = getGroup(groupId);
+        UserModel user = getUser(userId);
+        dispatcher.dispatchUserModificationToAll(client -> client.update(user));
+
+        // Step 2: delayed GROUP update :
+        // if several users are added to the group simultaneously in different Keycloack sessions
+        // update the group in the context of the current session may not reflect those other changes
+        // We trigger a delayed update by setting an attribute on the group (that will be handled by ScimBackgroundGroupMembershipUpdaters)
+        group.setSingleAttribute(ScimBackgroundGroupMembershipUpdater.GROUP_DIRTY_SINCE_ATTRIBUTE_NAME, "" + System.currentTimeMillis());
+    }
+
+    private void handleRoleMappingEvent(AdminEvent roleMappingEvent, ScimResourceType type, KeycloakId id) {
+        LOGGER.infof("[SCIM] Propagate RoleMapping %s - %s %s", roleMappingEvent.getOperationType(), type, id);
+        switch (type) {
+            case USER -> {
+                UserModel user = getUser(id);
+                dispatcher.dispatchUserModificationToAll(client -> client.update(user));
+            }
+            case GROUP -> {
+                GroupModel group = getGroup(id);
+                session.users()
+                        .getGroupMembersStream(session.getContext().getRealm(), group)
+                        .forEach(user ->
+                                dispatcher.dispatchUserModificationToAll(client -> client.update(user)
+                                ));
+            }
+            default -> {
+                // No other type is relevant for propagation
+            }
+        }
+    }
+
+    private void handleScimEndpointConfigurationEvent(AdminEvent event, String id) {
+        // In case of a component deletion
+        if (event.getOperationType() == OperationType.DELETE) {
+            // Check if it was a Scim endpoint configuration, and forward deletion if so
+            Stream<ComponentModel> scimEndpointConfigurationsWithDeletedId = session.getContext().getRealm().getComponentsStream()
+                    .filter(m -> ScimEndpointConfigurationStorageProviderFactory.ID.equals(m.getProviderId())
+                                 && id.equals(m.getId()));
+            if (scimEndpointConfigurationsWithDeletedId.iterator().hasNext()) {
+                LOGGER.infof("[SCIM] SCIM Endpoint configuration DELETE - %s ", id);
+                dispatcher.refreshActiveScimEndpoints();
+            }
+        } else {
+            // In case of CREATE or UPDATE, we can directly use the string representation
+            // to check if it defines a SCIM endpoint (faster)
+            if (event.getRepresentation() != null
+                && event.getRepresentation().contains("\"providerId\":\"scim\"")) {
+                LOGGER.infof("[SCIM] SCIM Endpoint configuration CREATE - %s ", id);
+                dispatcher.refreshActiveScimEndpoints();
+            }
+        }
+
+    }
+
+
+    private UserModel getUser(KeycloakId id) {
+        return keycloakDao.getUserById(id);
+    }
+
+    private GroupModel getGroup(KeycloakId id) {
+        return keycloakDao.getGroupById(id);
+    }
+
+    @Override
+    public void close() {
+        dispatcher.close();
+    }
+
+
+}

federation/scim/src/main/java/sh/libre/scim/event/ScimEventListenerProviderFactory.java

@@ -0,0 +1,36 @@
+package sh.libre.scim.event;
+
+import org.keycloak.Config.Scope;
+import org.keycloak.events.EventListenerProvider;
+import org.keycloak.events.EventListenerProviderFactory;
+import org.keycloak.models.KeycloakSession;
+import org.keycloak.models.KeycloakSessionFactory;
+
+public class ScimEventListenerProviderFactory implements EventListenerProviderFactory {
+
+    @Override
+    public EventListenerProvider create(KeycloakSession session) {
+        return new ScimEventListenerProvider(session);
+    }
+
+    @Override
+    public String getId() {
+        return "scim";
+    }
+
+    @Override
+    public void init(Scope config) {
+        // Nothing to initialize
+    }
+
+    @Override
+    public void postInit(KeycloakSessionFactory factory) {
+        // Nothing to initialize
+    }
+
+    @Override
+    public void close() {
+        // Nothing to close
+    }
+
+}

federation/scim/src/main/java/sh/libre/scim/jpa/ScimResourceDao.java

@@ -0,0 +1,96 @@
+package sh.libre.scim.jpa;
+
+import jakarta.persistence.EntityManager;
+import jakarta.persistence.NoResultException;
+import jakarta.persistence.TypedQuery;
+import org.keycloak.connections.jpa.JpaConnectionProvider;
+import org.keycloak.models.KeycloakSession;
+import sh.libre.scim.core.service.EntityOnRemoteScimId;
+import sh.libre.scim.core.service.KeycloakId;
+import sh.libre.scim.core.service.ScimResourceType;
+
+import java.util.Optional;
+
+public class ScimResourceDao {
+
+    private final String realmId;
+
+    private final String componentId;
+
+    private final EntityManager entityManager;
+
+    private ScimResourceDao(String realmId, String componentId, EntityManager entityManager) {
+        this.realmId = realmId;
+        this.componentId = componentId;
+        this.entityManager = entityManager;
+    }
+
+    public static ScimResourceDao newInstance(KeycloakSession keycloakSession, String componentId) {
+        String realmId = keycloakSession.getContext().getRealm().getId();
+        EntityManager entityManager = keycloakSession.getProvider(JpaConnectionProvider.class).getEntityManager();
+        return new ScimResourceDao(realmId, componentId, entityManager);
+    }
+
+    private EntityManager getEntityManager() {
+        return entityManager;
+    }
+
+    private String getRealmId() {
+        return realmId;
+    }
+
+    private String getComponentId() {
+        return componentId;
+    }
+
+    public void create(KeycloakId id, EntityOnRemoteScimId externalId, ScimResourceType type) {
+        ScimResourceMapping entity = new ScimResourceMapping();
+        entity.setType(type.name());
+        entity.setExternalId(externalId.asString());
+        entity.setComponentId(componentId);
+        entity.setRealmId(realmId);
+        entity.setId(id.asString());
+        entityManager.persist(entity);
+    }
+
+    private TypedQuery<ScimResourceMapping> getScimResourceTypedQuery(String queryName, String id, ScimResourceType type) {
+        return getEntityManager()
+                .createNamedQuery(queryName, ScimResourceMapping.class)
+                .setParameter("type", type.name())
+                .setParameter("realmId", getRealmId())
+                .setParameter("componentId", getComponentId())
+                .setParameter("id", id);
+    }
+
+    public Optional<ScimResourceMapping> findByExternalId(EntityOnRemoteScimId externalId, ScimResourceType type) {
+        try {
+            return Optional.of(
+                    getScimResourceTypedQuery("findByExternalId", externalId.asString(), type).getSingleResult()
+            );
+        } catch (NoResultException e) {
+            return Optional.empty();
+        }
+    }
+
+    public Optional<ScimResourceMapping> findById(KeycloakId keycloakId, ScimResourceType type) {
+        try {
+            return Optional.of(
+                    getScimResourceTypedQuery("findById", keycloakId.asString(), type).getSingleResult()
+            );
+        } catch (NoResultException e) {
+            return Optional.empty();
+        }
+    }
+
+    public Optional<ScimResourceMapping> findUserById(KeycloakId id) {
+        return findById(id, ScimResourceType.USER);
+    }
+
+    public Optional<ScimResourceMapping> findUserByExternalId(EntityOnRemoteScimId externalId) {
+        return findByExternalId(externalId, ScimResourceType.USER);
+    }
+
+    public void delete(ScimResourceMapping resource) {
+        entityManager.remove(resource);
+    }
+}

federation/scim/src/main/java/sh/libre/scim/jpa/ScimResourceId.java

@@ -0,0 +1,83 @@
+package sh.libre.scim.jpa;
+
+import org.apache.commons.lang3.StringUtils;
+
+import java.io.Serializable;
+import java.util.Objects;
+
+public class ScimResourceId implements Serializable {
+    private String id;
+    private String realmId;
+    private String componentId;
+    private String type;
+    private String externalId;
+
+    public ScimResourceId() {
+    }
+
+    public ScimResourceId(String id, String realmId, String componentId, String type, String externalId) {
+        this.setId(id);
+        this.setRealmId(realmId);
+        this.setComponentId(componentId);
+        this.setType(type);
+        this.setExternalId(externalId);
+    }
+
+    public String getId() {
+        return id;
+    }
+
+    public void setId(String id) {
+        this.id = id;
+    }
+
+    public String getRealmId() {
+        return realmId;
+    }
+
+    public void setRealmId(String realmId) {
+        this.realmId = realmId;
+    }
+
+    public String getComponentId() {
+        return componentId;
+    }
+
+    public void setComponentId(String componentId) {
+        this.componentId = componentId;
+    }
+
+    public String getType() {
+        return type;
+    }
+
+    public void setType(String type) {
+        this.type = type;
+    }
+
+    public String getExternalId() {
+        return externalId;
+    }
+
+    public void setExternalId(String externalId) {
+        this.externalId = externalId;
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        if (this == other)
+            return true;
+        if (!(other instanceof ScimResourceId o))
+            return false;
+        return (StringUtils.equals(o.id, id) &&
+                StringUtils.equals(o.realmId, realmId) &&
+                StringUtils.equals(o.componentId, componentId) &&
+                StringUtils.equals(o.type, type) &&
+                StringUtils.equals(o.externalId, externalId));
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(realmId, componentId, type, id, externalId);
+    }
+}

federation/scim/src/main/java/sh/libre/scim/jpa/ScimResourceMapping.java

@@ -0,0 +1,89 @@
+package sh.libre.scim.jpa;
+
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.IdClass;
+import jakarta.persistence.NamedQueries;
+import jakarta.persistence.NamedQuery;
+import jakarta.persistence.Table;
+import sh.libre.scim.core.service.EntityOnRemoteScimId;
+import sh.libre.scim.core.service.KeycloakId;
+
+@Entity
+@IdClass(ScimResourceId.class)
+@Table(name = "SCIM_RESOURCE_MAPPING")
+@NamedQueries({
+        @NamedQuery(name = "findById", query = "from ScimResourceMapping where realmId = :realmId and componentId = :componentId and type = :type and id = :id"),
+        @NamedQuery(name = "findByExternalId", query = "from ScimResourceMapping where realmId = :realmId and componentId = :componentId and type = :type and externalId = :id")
+})
+public class ScimResourceMapping {
+
+    @Id
+    @Column(name = "ID", nullable = false)
+    private String id;
+
+    @Id
+    @Column(name = "REALM_ID", nullable = false)
+    private String realmId;
+
+    @Id
+    @Column(name = "COMPONENT_ID", nullable = false)
+    private String componentId;
+
+    @Id
+    @Column(name = "TYPE", nullable = false)
+    private String type;
+
+    @Id
+    @Column(name = "EXTERNAL_ID", nullable = false)
+    private String externalId;
+
+    public String getId() {
+        return id;
+    }
+
+    public void setId(String id) {
+        this.id = id;
+    }
+
+    public String getRealmId() {
+        return realmId;
+    }
+
+    public void setRealmId(String realmId) {
+        this.realmId = realmId;
+    }
+
+    public String getComponentId() {
+        return componentId;
+    }
+
+    public void setComponentId(String componentId) {
+        this.componentId = componentId;
+    }
+
+    public String getExternalId() {
+        return externalId;
+    }
+
+    public void setExternalId(String externalId) {
+        this.externalId = externalId;
+    }
+
+    public String getType() {
+        return type;
+    }
+
+    public void setType(String type) {
+        this.type = type;
+    }
+
+    public KeycloakId getIdAsKeycloakId() {
+        return new KeycloakId(id);
+    }
+
+    public EntityOnRemoteScimId getExternalIdAsEntityOnRemoteScimId() {
+        return new EntityOnRemoteScimId(externalId);
+    }
+}

federation/scim/src/main/java/sh/libre/scim/jpa/ScimResourceProvider.java

@@ -0,0 +1,29 @@
+package sh.libre.scim.jpa;
+
+import org.keycloak.connections.jpa.entityprovider.JpaEntityProvider;
+
+import java.util.Collections;
+import java.util.List;
+
+public class ScimResourceProvider implements JpaEntityProvider {
+
+    @Override
+    public List<Class<?>> getEntities() {
+        return Collections.singletonList(ScimResourceMapping.class);
+    }
+
+    @Override
+    public String getChangelogLocation() {
+        return "META-INF/scim-resource-changelog.xml";
+    }
+
+    @Override
+    public void close() {
+        // Nothing to close
+    }
+
+    @Override
+    public String getFactoryId() {
+        return ScimResourceProviderFactory.ID;
+    }
+}

federation/scim/src/main/java/sh/libre/scim/jpa/ScimResourceProviderFactory.java

@@ -0,0 +1,39 @@
+package sh.libre.scim.jpa;
+
+import org.keycloak.Config.Scope;
+import org.keycloak.connections.jpa.entityprovider.JpaEntityProvider;
+import org.keycloak.connections.jpa.entityprovider.JpaEntityProviderFactory;
+import org.keycloak.models.KeycloakSession;
+import org.keycloak.models.KeycloakSessionFactory;
+
+public class ScimResourceProviderFactory implements JpaEntityProviderFactory {
+
+    static final String ID = "scim-resource";
+
+    @Override
+    public JpaEntityProvider create(KeycloakSession session) {
+        return new ScimResourceProvider();
+    }
+
+    @Override
+    public String getId() {
+        return ID;
+    }
+
+    @Override
+    public void init(Scope scope) {
+        // Nothing to initialise
+    }
+
+    @Override
+    public void postInit(KeycloakSessionFactory sessionFactory) {
+        // Nothing to do
+    }
+
+
+    @Override
+    public void close() {
+        // Nothing to close
+    }
+
+}

federation/scim/src/main/resources/META-INF/jboss-deployment-structure.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<jboss-deployment-structure>
+    <deployment>
+        <dependencies>
+            <module name="org.keycloak.keycloak-services" />
+            <module name="org.keycloak.keycloak-model-jpa" />
+            <module name="org.hibernate" />
+        </dependencies>
+    </deployment>
+</jboss-deployment-structure>

federation/scim/src/main/resources/META-INF/scim-resource-changelog.xml

@@ -0,0 +1,35 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<databaseChangeLog xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
+                   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+                   xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.1.xsd">
+    <changeSet author="contact@indiehosters.net" id="scim-resource-1.0">
+
+        <createTable tableName="SCIM_RESOURCE_MAPPING">
+            <column name="ID" type="VARCHAR(36)">
+                <constraints nullable="false"/>
+            </column>
+            <column name="REALM_ID" type="VARCHAR(36)">
+                <constraints nullable="false"/>
+            </column>
+            <column name="TYPE" type="VARCHAR(36)">
+                <constraints nullable="false"/>
+            </column>
+            <column name="COMPONENT_ID" type="VARCHAR(36)">
+                <constraints nullable="false"/>
+            </column>
+            <column name="EXTERNAL_ID" type="VARCHAR(36)">
+                <constraints nullable="false"/>
+            </column>
+        </createTable>
+
+        <addPrimaryKey constraintName="PK_SCIM_RESOURCE_MAPPING" tableName="SCIM_RESOURCE_MAPPING"
+                       columnNames="ID,REALM_ID,TYPE,COMPONENT_ID,EXTERNAL_ID"/>
+        <addForeignKeyConstraint baseTableName="SCIM_RESOURCE_MAPPING" baseColumnNames="REALM_ID"
+                                 constraintName="FK_SCIM_RESOURCE_MAPPING_REALM" referencedTableName="REALM"
+                                 referencedColumnNames="ID" onDelete="CASCADE" onUpdate="CASCADE"/>
+        <addForeignKeyConstraint baseTableName="SCIM_RESOURCE_MAPPING" baseColumnNames="COMPONENT_ID"
+                                 constraintName="FK_SCIM_RESOURCE_MAPPING_COMPONENT" referencedTableName="COMPONENT"
+                                 referencedColumnNames="ID" onDelete="CASCADE" onUpdate="CASCADE"/>
+    </changeSet>
+
+</databaseChangeLog>

federation/scim/src/main/resources/META-INF/services/org.keycloak.connections.jpa.entityprovider.JpaEntityProviderFactory

@@ -0,0 +1 @@
+sh.libre.scim.jpa.ScimResourceProviderFactory

federation/scim/src/main/resources/META-INF/services/org.keycloak.events.EventListenerProviderFactory

@@ -0,0 +1 @@
+sh.libre.scim.event.ScimEventListenerProviderFactory

federation/scim/src/main/resources/META-INF/services/org.keycloak.storage.UserStorageProviderFactory

@@ -0,0 +1 @@
+sh.libre.scim.core.ScimEndpointConfigurationStorageProviderFactory

pom.xml

@@ -926,6 +926,11 @@
                 <artifactId>keycloak-ldap-federation</artifactId>
                 <version>${project.version}</version>
             </dependency>
+            <dependency>
+                <groupId>org.keycloak</groupId>
+                <artifactId>keycloak-scim-federation</artifactId>
+                <version>${project.version}</version>
+            </dependency>
             <dependency>
                 <groupId>org.keycloak</groupId>
                 <artifactId>keycloak-dependencies-server-min</artifactId>

quarkus/runtime/pom.xml

@@ -324,6 +324,16 @@
                 </exclusion>
             </exclusions>
         </dependency>
+        <dependency>
+            <groupId>org.keycloak</groupId>
+            <artifactId>keycloak-scim-federation</artifactId>
+            <exclusions>
+                <exclusion>
+                    <groupId>*</groupId>
+                    <artifactId>*</artifactId>
+                </exclusion>
+            </exclusions>
+        </dependency>
         <dependency>
             <groupId>org.keycloak</groupId>
             <artifactId>keycloak-config-api</artifactId>