Logging is done on a per-category basis in Keycloak. You can configure logging for the root log level, or for more specific categories like `org.hibernate` or `org.keycloak`. In this guide, you will learn how to configure logging.
using one of the levels mentioned in the table above. When no log level configuration exists for a more specific category logger (see below), the enclosing category is used instead. When there is no enclosing category, the root logger level is used.
Setting the log level is case-insensitive, so you could either use for example `DEBUG` or `debug`.
When you accidentally set the log level twice, for example when you invoke `--log-level=info,...,debug,...` the last occurence in the list will be used as the log level, so for the example the root logger would be set to `DEBUG`.
=== Configuring category-specific log levels
It is possible to set a different log level for specific areas in Keycloak. To enable category-specific logging, provide a comma-separated list containing the categories you want another log level than for the root category to the `--log-level` configuration:
A configuration that applies to a category also applies to all sub-categories of that category, unless a more specific matching sub-category configuration is provided in the list.
The example above sets the root log level for all loggers to INFO, and the hibernate log level in general to debug. But as we don't want SQL abstract syntax trees to make the log output verbose, we set the more specific sub category `org.hibernate.hql.internal.ast` to info, so the SQL abstract syntax trees, which would be shown at `debug` level, don't show up anymore.
The available handlers are `console` and `file`. The more specific handler configuration mentioned below will only take effect when the handler is added to this comma-separated list.
Be aware that you need to escape characters when invoking commands containing special shell characters such as `;` using the CLI, so you might want to set it in the configuration file instead.
{"timestamp":"2022-02-25T10:31:32.452+01:00","sequence":8442,"loggerClassName":"org.jboss.logging.Logger","loggerName":"io.quarkus","level":"INFO","message":"Keycloak 18.0.0-SNAPSHOT on JVM (powered by Quarkus 2.7.2.Final) started in 3.253s. Listening on: http://0.0.0.0:8080","threadName":"main","threadId":1,"mdc":{},"ndc":"","hostName":"host-name","processName":"QuarkusEntryPoint","processId":36946}
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When using JSON output, colors are disabled and the format settings set by `--log-console-format` will not apply.
To use unstructured logging, run the following command:
2022-03-02 10:36:50,603 INFO [io.quarkus] (main) Keycloak 18.0.0-SNAPSHOT on JVM (powered by Quarkus 2.7.2.Final) started in 3.615s. Listening on: http://0.0.0.0:8080
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=== Colors
Colored console log output for unstructured logs is disabled by default. It may lead to better readability, but can cause problems when shipping logs to external log aggregation systems. If you want to enable or disable color-coded console log output, run following command:
Please make sure the location for the logfile is writeable. If not, an error will be thrown at start-up. Keycloak will start correctly, but no file containing logs will be created.
=== Configuring the file handler format
You can configure a different logging format for the file log handler by running the following command:
At the time of writing, the logging features of the quarkus based Keycloak are basic, yet powerful. Nevertheless, expect more to come and feel free to join the https://github.com/keycloak/keycloak/discussions/8870[discussion] at GitHub.
When you need a temporary solution, e.g. for logging to a file or using syslog instead of console, you can check out the https://github.com/keycloak/keycloak/discussions/8870[Quarkus logging guide]. It is possible to use all properties mentioned there, as long as no other than the base logging dependency is involved. For example it is possible to set the log handler to file, but not to use json output, yet, as you would need to provide another dependency for json output to work.
