Add simple metrics endpoint for rageshake.

.github/workflows/build.yaml

@@ -33,19 +33,20 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-go@v3
         with:
-          go-version: 1.16
+          go-version: 1.20
       - name: Install lint deps
         run: |
-          go get golang.org/x/lint/golint
+          mkdir ~/go
+          go install golang.org/x/lint/golint
           go install golang.org/x/tools/go/analysis/passes/shadow/cmd/shadow
-          go get github.com/fzipp/gocyclo/cmd/gocyclo
+          go install github.com/fzipp/gocyclo/cmd/gocyclo
       - name: lint
         run: ./scripts/lint.sh
   test:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        golang: ["1.17", "1.16"]
+        golang: ["1.21", "1.20"]
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-go@v3

Dockerfile

@@ -1,4 +1,4 @@
-ARG GO_VERSION=1.17
+ARG GO_VERSION=1.20
 ARG DEBIAN_VERSION=11
 ARG DEBIAN_VERSION_NAME=bullseye
 

README.md

@@ -17,11 +17,17 @@ Optional parameters:
    [rageshake.sample.yaml](rageshake.sample.yaml) for more information.
  * `-listen <address>`: TCP network address to listen for HTTP requests
    on. Example: `:9110`.
+ * `-metrics <address>`: TCP network address to listen for HTTP requests
+   for prometheus metrics on. Example: `:9111`. Defaults to not being served.
 
 ## HTTP endpoints
 
 The following HTTP endpoints are exposed:
 
+### GET `/health`
+
+Returns a simple "ok" if the server is healthy, for use with automated healthchecks.
+
 ### GET `/api/listing/`
 
 Serves submitted bug reports. Protected by basic HTTP auth using the
@@ -100,6 +106,10 @@ The response (if successful) will be a JSON object with the following fields:
 * `report_url`: A URL where the user can track their bug report. Omitted if
   issue submission was disabled.
 
+### /metrics
+
+If the metrics address is configured with `-metrics` then prometheus metrics are visible here.
+
 ## Notifications
 
 You can get notifications when a new rageshake arrives on the server.

changelog.d/82.feature

@@ -0,0 +1 @@
+Add new -metrics flag to optionally enable prometheus metrics listener.

go.mod

@@ -5,7 +5,9 @@ go 1.16
 require (
 	github.com/google/go-github v0.0.0-20170401000335-12363ffc1001
 	github.com/jordan-wright/email v4.0.1-0.20200824153738-3f5bafa1cd84+incompatible
+	github.com/prometheus/client_golang v1.17.0 // indirect
 	github.com/xanzy/go-gitlab v0.50.2
-	golang.org/x/oauth2 v0.0.0-20181106182150-f42d05182288
-	gopkg.in/yaml.v2 v2.2.8
+	golang.org/x/oauth2 v0.8.0
+	golang.org/x/tools v0.6.0 // indirect
+	gopkg.in/yaml.v2 v2.4.0
 )

main.go

@@ -31,7 +31,8 @@ import (
 	"time"
 
 	"github.com/google/go-github/github"
-	"github.com/xanzy/go-gitlab"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+        "github.com/xanzy/go-gitlab"
 	"golang.org/x/oauth2"
 
 	"gopkg.in/yaml.v2"
@@ -40,6 +41,8 @@ import (
 var configPath = flag.String("config", "rageshake.yaml", "The path to the config file. For more information, see the config file in this repository.")
 var bindAddr = flag.String("listen", ":9110", "The port to listen on.")
 
+var metricsBindAddr = flag.String("metrics", "", "The port to listen on for metrics.")
+
 type config struct {
 	// Username and password required to access the bug report listings
 	BugsUser string `yaml:"listings_auth_user"`
@@ -180,7 +183,14 @@ func main() {
 	http.HandleFunc("/health", func(w http.ResponseWriter, r *http.Request) {
 		fmt.Fprint(w, "ok")
 	})
-
+        if *metricsBindAddr != "" {
+                metricsMux := http.NewServeMux()
+                metricsMux.Handle("/metrics", promhttp.Handler())
+		go func() {
+	                log.Println("Metrics Listening on", *metricsBindAddr)
+			http.ListenAndServe(*metricsBindAddr, metricsMux)
+		}()
+        }
 	log.Println("Listening on", *bindAddr)
 
 	log.Fatal(http.ListenAndServe(*bindAddr, nil))