From 71f31b43545a4911cd07eb50ceea42b155bf6bca Mon Sep 17 00:00:00 2001
From: David Christofas <dchristofas@owncloud.com>
Date: Wed, 29 Jul 2020 11:02:03 +0200
Subject: [PATCH] add metrics endpoint

Signed-off-by: David Christofas <dchristofas@owncloud.com>
---
 changelog/unreleased/serve-metrics.md |  5 ++++
 pkg/command/server.go                 | 35 ++++++++++++++++++++++
 pkg/server/debug/option.go            | 42 ++++++++++++++++++++++++++
 pkg/server/debug/server.go            | 43 +++++++++++++++++++++++++++
 4 files changed, 125 insertions(+)
 create mode 100644 changelog/unreleased/serve-metrics.md
 create mode 100644 pkg/server/debug/option.go
 create mode 100644 pkg/server/debug/server.go

diff --git a/changelog/unreleased/serve-metrics.md b/changelog/unreleased/serve-metrics.md
new file mode 100644
index 000000000..72c003beb
--- /dev/null
+++ b/changelog/unreleased/serve-metrics.md
@@ -0,0 +1,5 @@
+Enhancement: serve the metrics endpoint
+
+Added the metrics endpoint to be able to monitor this service like the other services
+
+https://github.com/owncloud/ocis-thumbnails/issues/37
diff --git a/pkg/command/server.go b/pkg/command/server.go
index 833aaf5fe..44a89a79f 100644
--- a/pkg/command/server.go
+++ b/pkg/command/server.go
@@ -17,6 +17,7 @@ import (
 	"github.com/owncloud/ocis-thumbnails/pkg/config"
 	"github.com/owncloud/ocis-thumbnails/pkg/flagset"
 	"github.com/owncloud/ocis-thumbnails/pkg/metrics"
+	"github.com/owncloud/ocis-thumbnails/pkg/server/debug"
 	"github.com/owncloud/ocis-thumbnails/pkg/server/grpc"
 	"go.opencensus.io/stats/view"
 	"go.opencensus.io/trace"
@@ -145,6 +146,40 @@ func Server(cfg *config.Config) *cli.Command {
 				cancel()
 			})
 
+			server, err := debug.Server(
+				debug.Logger(logger),
+				debug.Config(cfg),
+			)
+
+			if err != nil {
+				logger.Info().
+					Err(err).
+					Str("transport", "debug").
+					Msg("Failed to initialize server")
+
+				return err
+			}
+
+			gr.Add(func() error {
+				return server.ListenAndServe()
+			}, func(_ error) {
+				ctx, timeout := context.WithTimeout(ctx, 5*time.Second)
+
+				defer timeout()
+				defer cancel()
+
+				if err := server.Shutdown(ctx); err != nil {
+					logger.Info().
+						Err(err).
+						Str("transport", "debug").
+						Msg("Failed to shutdown server")
+				} else {
+					logger.Info().
+						Str("transport", "debug").
+						Msg("Shutting down server")
+				}
+			})
+
 			{
 				stop := make(chan os.Signal, 1)
 
diff --git a/pkg/server/debug/option.go b/pkg/server/debug/option.go
new file mode 100644
index 000000000..3349a7875
--- /dev/null
+++ b/pkg/server/debug/option.go
@@ -0,0 +1,42 @@
+package debug
+
+import (
+	"github.com/owncloud/ocis-pkg/v2/log"
+	"github.com/owncloud/ocis-thumbnails/pkg/config"
+)
+
+// Option defines a single option function.
+type Option func(o *Options)
+
+// Options defines the available options for this package.
+type Options struct {
+	Name    string
+	Address string
+	Logger  log.Logger
+	Config  *config.Config
+}
+
+// newOptions initializes the available default options.
+func newOptions(opts ...Option) Options {
+	opt := Options{}
+
+	for _, o := range opts {
+		o(&opt)
+	}
+
+	return opt
+}
+
+// Logger provides a function to set the logger option.
+func Logger(val log.Logger) Option {
+	return func(o *Options) {
+		o.Logger = val
+	}
+}
+
+// Config provides a function to set the config option.
+func Config(val *config.Config) Option {
+	return func(o *Options) {
+		o.Config = val
+	}
+}
diff --git a/pkg/server/debug/server.go b/pkg/server/debug/server.go
new file mode 100644
index 000000000..cb3603536
--- /dev/null
+++ b/pkg/server/debug/server.go
@@ -0,0 +1,43 @@
+package debug
+
+import (
+	"io"
+	"net/http"
+
+	"github.com/owncloud/ocis-pkg/v2/service/debug"
+	"github.com/owncloud/ocis-thumbnails/pkg/config"
+	"github.com/owncloud/ocis-thumbnails/pkg/version"
+)
+
+// Server initializes the debug service and server.
+func Server(opts ...Option) (*http.Server, error) {
+	options := newOptions(opts...)
+
+	return debug.NewService(
+		debug.Logger(options.Logger),
+		debug.Name(options.Config.Server.Name),
+		debug.Version(version.String),
+		debug.Address(options.Config.Debug.Addr),
+		debug.Token(options.Config.Debug.Token),
+		debug.Pprof(options.Config.Debug.Pprof),
+		debug.Zpages(options.Config.Debug.Zpages),
+		debug.Health(health(options.Config)),
+		debug.Ready(ready(options.Config)),
+	), nil
+}
+
+func health(cfg *config.Config) func(http.ResponseWriter, *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "text/plain")
+		w.WriteHeader(http.StatusOK)
+		io.WriteString(w, http.StatusText(http.StatusOK))
+	}
+}
+
+func ready(cfg *config.Config) func(http.ResponseWriter, *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "text/plain")
+		w.WriteHeader(http.StatusOK)
+		io.WriteString(w, http.StatusText(http.StatusOK))
+	}
+}