feat: add health check to telemetry server

Signed-off-by: Mark Sagi-Kazar <mark.sagikazar@gmail.com>

cmd/dex/serve.go

@@ -14,6 +14,9 @@ import (
 	"syscall"
 	"time"
 
+	gosundheit "github.com/AppsFlyer/go-sundheit"
+	"github.com/AppsFlyer/go-sundheit/checks"
+	gosundheithttp "github.com/AppsFlyer/go-sundheit/http"
 	"github.com/ghodss/yaml"
 	grpcprometheus "github.com/grpc-ecosystem/go-grpc-prometheus"
 	"github.com/oklog/run"
@@ -325,6 +328,28 @@ func runServe(options serveOptions) error {
 	telemetryServ := http.NewServeMux()
 	telemetryServ.Handle("/metrics", promhttp.HandlerFor(prometheusRegistry, promhttp.HandlerOpts{}))
 
+	// Configure health checker
+	healthChecker := gosundheit.New()
+	{
+		handler := gosundheithttp.HandleHealthJSON(healthChecker)
+		telemetryServ.Handle("/healthz", handler)
+
+		// Kubernetes style health checks
+		telemetryServ.HandleFunc("/healthz/live", func(w http.ResponseWriter, _ *http.Request) {
+			_, _ = w.Write([]byte("ok"))
+		})
+		telemetryServ.Handle("/healthz/ready", handler)
+	}
+
+	healthChecker.RegisterCheck(&gosundheit.Config{
+		Check: &checks.CustomCheck{
+			CheckName: "storage",
+			CheckFunc: storage.NewCustomHealthCheckFunc(serverConfig.Storage, serverConfig.Now),
+		},
+		ExecutionPeriod:  15 * time.Second,
+		InitiallyPassing: true,
+	})
+
 	var gr run.Group
 	if c.Telemetry.HTTP != "" {
 		telemetrySrv := &http.Server{Addr: c.Telemetry.HTTP, Handler: telemetryServ}

go.mod

@@ -3,6 +3,7 @@ module github.com/dexidp/dex
 go 1.15
 
 require (
+	github.com/AppsFlyer/go-sundheit v0.3.1
 	github.com/Microsoft/hcsshim v0.8.14 // indirect
 	github.com/beevik/etree v1.1.0
 	github.com/coreos/go-oidc/v3 v3.0.0

go.sum

@@ -13,6 +13,8 @@ cloud.google.com/go/firestore v1.1.0/go.mod h1:ulACoGHTpvq5r8rxGJ4ddJZBZqakUQqCl
 cloud.google.com/go/pubsub v1.0.1/go.mod h1:R0Gpsv3s54REJCy4fxDixWD93lHJMoZTyQ2kNxGRt3I=
 cloud.google.com/go/storage v1.0.0/go.mod h1:IhtSnM/ZTZV8YYJWCY8RULGVqBDmpoyjwiyrjsg+URw=
 dmitri.shuralyov.com/gpu/mtl v0.0.0-20190408044501-666a987793e9/go.mod h1:H6x//7gZCb22OMCxBHrMx7a5I7Hp++hsVxbQ4BYO7hU=
+github.com/AppsFlyer/go-sundheit v0.3.1 h1:Zqnr3wV3WQmXonc234k9XZAoV2KHUHw3osR5k2iHQZE=
+github.com/AppsFlyer/go-sundheit v0.3.1/go.mod h1:iZ8zWMS7idcvmqewf5mEymWWgoOiG/0WD4+aeh+heX4=
 github.com/Azure/go-ansiterm v0.0.0-20170929234023-d6e3b3328b78 h1:w+iIsaOQNcT7OZ575w+acHgRric5iCyQh+xv+KJ4HB8=
 github.com/Azure/go-ansiterm v0.0.0-20170929234023-d6e3b3328b78/go.mod h1:LmzpDX56iTiv29bbRTIsUNlaFfuhWRQBWjQdVyAevI8=
 github.com/BurntSushi/toml v0.3.1 h1:WXkYYl6Yr3qBf1K79EBnL4mak0OimBfB0XUf9Vl28OQ=
@@ -102,6 +104,8 @@ github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7
 github.com/fatih/color v1.7.0/go.mod h1:Zm6kSWBoL9eyXnKyktHP6abPY2pDugNf5KwzbycvMj4=
 github.com/felixge/httpsnoop v1.0.1 h1:lvB5Jl89CsZtGIWuTcDM1E/vkVs49/Ml7JJe07l8SPQ=
 github.com/felixge/httpsnoop v1.0.1/go.mod h1:m8KPJKqk1gH5J9DgRY2ASl2lWCfGKXixSwevea8zH2U=
+github.com/fortytw2/leaktest v1.3.0 h1:u8491cBMTQ8ft8aeV+adlcytMZylmA5nnwwkRZjI8vw=
+github.com/fortytw2/leaktest v1.3.0/go.mod h1:jDsjWgpAGjm2CA7WthBh/CdZYEPF31XHquHwclZch5g=
 github.com/fsnotify/fsnotify v1.4.7 h1:IXs+QLmnXW2CcXuY+8Mzv/fWEsPGWxqefPtCP5CnV9I=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
 github.com/ghodss/yaml v1.0.0 h1:wQHKEahhL6wmXdzwWG11gIVCkOv05bNOh+Rxn0yngAk=
@@ -339,6 +343,8 @@ github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An
 github.com/spf13/viper v1.7.0/go.mod h1:8WkrPz2fc9jxqZNCJI/76HCieCp4Q8HaLFoCha5qpdg=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.2.0 h1:Hbg2NidpLE8veEBkEZTL3CvlkUIVzuU9jDplZO54c48=
+github.com/stretchr/objx v0.2.0/go.mod h1:qt09Ya8vawLte6SNmTgCsAVtYtaKzEcn8ATUoHMkEqE=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=

storage/health.go

+package storage
+
+import (
+	"fmt"
+	"time"
+)
+
+// NewCustomHealthCheckFunc returns a new health check function.
+func NewCustomHealthCheckFunc(s Storage, now func() time.Time) func() (details interface{}, err error) {
+	return func() (details interface{}, err error) {
+		a := AuthRequest{
+			ID:       NewID(),
+			ClientID: NewID(),
+
+			// Set a short expiry so if the delete fails this will be cleaned up quickly by garbage collection.
+			Expiry: now().Add(time.Minute),
+		}
+
+		if err := s.CreateAuthRequest(a); err != nil {
+			return nil, fmt.Errorf("create auth request: %v", err)
+		}
+
+		if err := s.DeleteAuthRequest(a.ID); err != nil {
+			return nil, fmt.Errorf("delete auth request: %v", err)
+		}
+
+		return nil, nil
+	}
+}