From 8303048f5e2820a8647ee128c8e8464d8411349d Mon Sep 17 00:00:00 2001
From: Enrico Stahn <enrico.stahn@gmail.com>
Date: Thu, 22 Feb 2018 15:41:27 +1100
Subject: [PATCH] Add metrics "phpfpm_up" and "phpfpm_scrape_failures" to
 report on scraping issues (#2)

---
 phpfpm/exporter.go | 29 ++++++++++++++++++++++++-----
 phpfpm/phpfpm.go   | 27 ++++++++++++++++-----------
 2 files changed, 40 insertions(+), 16 deletions(-)

diff --git a/phpfpm/exporter.go b/phpfpm/exporter.go
index ae8dbc1..55c27b6 100644
--- a/phpfpm/exporter.go
+++ b/phpfpm/exporter.go
@@ -14,6 +14,7 @@
 package phpfpm
 
 import (
+	"fmt"
 	"github.com/prometheus/client_golang/prometheus"
 	"sync"
 )
@@ -27,6 +28,8 @@ type Exporter struct {
 	PoolManager PoolManager
 	mutex       sync.Mutex
 
+	up                  *prometheus.Desc
+	scrapeFailues       *prometheus.Desc
 	startSince          *prometheus.Desc
 	acceptedConnections *prometheus.Desc
 	listenQueue         *prometheus.Desc
@@ -45,6 +48,18 @@ func NewExporter(pm PoolManager) *Exporter {
 	return &Exporter{
 		PoolManager: pm,
 
+		up: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, "", "up"),
+			"Could PHP-FPM be reached?",
+			[]string{"pool"},
+			nil),
+
+		scrapeFailues: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, "", "scrape_failures"),
+			"The number of failures scraping from PHP-FPM.",
+			[]string{"pool"},
+			nil),
+
 		startSince: prometheus.NewDesc(
 			prometheus.BuildFQName(namespace, "", "start_since"),
 			"The number of seconds since FPM has started.",
@@ -121,6 +136,15 @@ func (e *Exporter) Collect(ch chan<- prometheus.Metric) {
 	e.PoolManager.Update()
 
 	for _, pool := range e.PoolManager.Pools {
+		ch <- prometheus.MustNewConstMetric(e.scrapeFailues, prometheus.CounterValue, float64(pool.ScrapeFailures))
+
+		if pool.ScrapeError != nil {
+			ch <- prometheus.MustNewConstMetric(e.up, prometheus.GaugeValue, 0)
+			log.Error("Error scraping PHP-FPM: %v", pool.ScrapeError)
+			continue
+		}
+
+		ch <- prometheus.MustNewConstMetric(e.up, prometheus.GaugeValue, 1, pool.Name)
 		ch <- prometheus.MustNewConstMetric(e.startSince, prometheus.CounterValue, float64(pool.AcceptedConnections), pool.Name)
 		ch <- prometheus.MustNewConstMetric(e.acceptedConnections, prometheus.CounterValue, float64(pool.StartSince), pool.Name)
 		ch <- prometheus.MustNewConstMetric(e.listenQueue, prometheus.GaugeValue, float64(pool.ListenQueue), pool.Name)
@@ -134,11 +158,6 @@ func (e *Exporter) Collect(ch chan<- prometheus.Metric) {
 		ch <- prometheus.MustNewConstMetric(e.slowRequests, prometheus.CounterValue, float64(pool.SlowRequests), pool.Name)
 	}
 
-	//if err := e.collect(ch); err != nil {
-	//	log.Errorf("Error scraping apache: %s", err)
-	//	e.scrapeFailures.Inc()
-	//	e.scrapeFailures.Collect(ch)
-	//}
 	return
 }
 
diff --git a/phpfpm/phpfpm.go b/phpfpm/phpfpm.go
index 35ea6aa..a48d3f1 100644
--- a/phpfpm/phpfpm.go
+++ b/phpfpm/phpfpm.go
@@ -41,7 +41,8 @@ type PoolManager struct {
 type Pool struct {
 	// The address of the pool, e.g. tcp://127.0.0.1:9000 or unix:///tmp/php-fpm.sock
 	Address             string        `json:"-"`
-	CollectionError     error         `json:"-"`
+	ScrapeError         error         `json:"-"`
+	ScrapeFailures      int64         `json:"-"`
 	Name                string        `json:"pool"`
 	ProcessManager      string        `json:"process manager"`
 	StartTime           timestamp     `json:"start time"`
@@ -108,14 +109,15 @@ func (pm *PoolManager) Update() (err error) {
 
 // Update will connect to PHP-FPM and retrieve the latest data for the pool.
 func (p *Pool) Update() (err error) {
-	p.CollectionError = nil
+	p.ScrapeError = nil
 
-	env := make(map[string]string)
-	env["SCRIPT_FILENAME"] = "/status"
-	env["SCRIPT_NAME"] = "/status"
-	env["SERVER_SOFTWARE"] = "go / php-fpm_exporter "
-	env["REMOTE_ADDR"] = "127.0.0.1"
-	env["QUERY_STRING"] = "json&full"
+	env := map[string]string{
+		"SCRIPT_FILENAME": "/status",
+		"SCRIPT_NAME":     "/status",
+		"SERVER_SOFTWARE": "go / php-fpm_exporter",
+		"REMOTE_ADDR":     "127.0.0.1",
+		"QUERY_STRING":    "json&full",
+	}
 
 	uri, err := url.Parse(p.Address)
 	if err != nil {
@@ -127,18 +129,20 @@ func (p *Pool) Update() (err error) {
 		return p.error(err)
 	}
 
+	defer fcgi.Close()
+
 	resp, err := fcgi.Get(env)
 	if err != nil {
 		return p.error(err)
 	}
 
+	defer resp.Body.Close()
+
 	content, err := ioutil.ReadAll(resp.Body)
 	if err != nil {
 		return p.error(err)
 	}
 
-	fcgi.Close()
-
 	log.Debugf("Pool[", p.Address, "]:", string(content))
 
 	if err = json.Unmarshal(content, &p); err != nil {
@@ -149,7 +153,8 @@ func (p *Pool) Update() (err error) {
 }
 
 func (p *Pool) error(err error) error {
-	p.CollectionError = err
+	p.ScrapeError = err
+	p.ScrapeFailures++
 	log.Error(err)
 	return err
 }