add prometheus metrics

.gitignore

@@ -10,3 +10,4 @@
 
 # Output of the go coverage tool, specifically when used with LiteIDE
 *.out
+.DS_Store

src/config/config.go

@@ -21,6 +21,7 @@ var (
 	ScCookieName      = getEnv("ADMINIO_COOKIE_NAME", "adminiosessionid")
 	OauthEnable, _    = strconv.ParseBool(getEnv("ADMINIO_OAUTH_ENABLE", "false"))
 	AuditLogEnable, _ = strconv.ParseBool(getEnv("ADMINIO_AUDIT_LOG_ENABLE", "false"))
+	MetricsEnable, _  = strconv.ParseBool(getEnv("ADMINIO_METRICS_ENABLE", "false"))
 	OauthProvider     = getEnv("ADMINIO_OAUTH_PROVIDER", "github")
 	OauthClientId     = getEnv("ADMINIO_OAUTH_CLIENT_ID", "my-github-oauth-app-client-id")
 	OauthClientSecret = getEnv("ADMINIO_OAUTH_CLIENT_SECRET", "my-github-oauth-app-secret")

src/go.mod

@@ -9,14 +9,17 @@ require (
 	github.com/gorilla/securecookie v1.1.1
 	github.com/imkira/go-interpol v1.1.0 // indirect
 	github.com/iris-contrib/middleware/cors v0.0.0-20191219204441-78279b78a367
+	github.com/iris-contrib/middleware/prometheus v0.0.0-20191219204441-78279b78a367
 	github.com/k0kubun/colorstring v0.0.0-20150214042306-9440f1994b88 // indirect
 	github.com/kataras/iris/v12 v12.1.8
 	github.com/markbates/goth v1.62.0
+	github.com/mattn/go-isatty v0.0.8 // indirect
 	github.com/minio/minio v0.0.0-20200315185552-c9212819afbf
 	github.com/minio/minio-go/v6 v6.0.50-0.20200306231101-b882ba63d570
 	github.com/moul/http2curl v1.0.0 // indirect
 	github.com/onsi/ginkgo v1.12.0 // indirect
 	github.com/onsi/gomega v1.9.0 // indirect
+	github.com/prometheus/client_golang v1.2.1
 	github.com/rzrbld/goth-provider-wso2 v0.0.0-20200321083654-32bbe73a67d4
 	github.com/sergi/go-diff v1.1.0 // indirect
 	github.com/shurcooL/sanitized_anchor_name v1.0.0 // indirect
@@ -26,4 +29,7 @@ require (
 	github.com/yudai/gojsondiff v1.0.0 // indirect
 	github.com/yudai/golcs v0.0.0-20170316035057-ecda9a501e82 // indirect
 	github.com/yudai/pp v2.0.1+incompatible // indirect
+	golang.org/x/net v0.0.0-20200320220750-118fecf932d8 // indirect
+	golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 // indirect
+	gopkg.in/yaml.v2 v2.2.8 // indirect
 )

src/handlers/metrics.go

@@ -0,0 +1,32 @@
+package handlers
+
+import (
+	"log"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+)
+
+var opsProcessed = promauto.NewGaugeVec(prometheus.GaugeOpts{
+	Name: "bucket_size_current",
+	Help: "bucket size in kbytes",
+}, []string{"bucket"})
+
+func RecordMetrics() {
+	go func() {
+		for {
+			du, err := madmClnt.DataUsageInfo()
+			if err != nil {
+				log.Print("Error while getting bucket size metrics from server")
+			} else {
+				if len(du.BucketsSizes) != 0 {
+					for k, v := range du.BucketsSizes {
+						opsProcessed.WithLabelValues(string(k)).Set(float64(v))
+					}
+				}
+			}
+			time.Sleep(30 * time.Minute)
+		}
+	}()
+}

src/main.go

@@ -2,7 +2,9 @@ package main
 
 import (
 	"fmt"
+
 	"github.com/iris-contrib/middleware/cors"
+	prometheusMiddleware "github.com/iris-contrib/middleware/prometheus"
 	iris "github.com/kataras/iris/v12"
 	"github.com/markbates/goth"
 	"github.com/markbates/goth/providers/amazon"
@@ -17,6 +19,7 @@ import (
 	"github.com/markbates/goth/providers/onedrive"
 	"github.com/markbates/goth/providers/salesforce"
 	"github.com/markbates/goth/providers/slack"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"github.com/rzrbld/goth-provider-wso2"
 
 	cnf "github.com/rzrbld/adminio-api/config"
@@ -54,6 +57,14 @@ func main() {
 		AllowCredentials: true,
 	})
 
+	// prometheus default metrics
+	if cnf.MetricsEnable {
+		m := prometheusMiddleware.New("adminio", 0.3, 1.2, 5.0)
+		hdl.RecordMetrics()
+		app.Use(m.ServeHTTP)
+		app.Get("/metrics", iris.FromStd(promhttp.Handler()))
+	}
+
 	v1auth := app.Party("/auth/", crs).AllowMethods(iris.MethodOptions)
 	{
 		v1auth.Get("/logout/", hdl.AuthLogout)