feat(prometheus): add new flag --prometheus-metrics-path

Makefile

@@ -68,6 +68,7 @@ PROMETHEUS_NAMESPACE=gotenberg
 PROMETHEUS_COLLECT_INTERVAL=1s
 PROMETHEUS_DISABLE_ROUTE_LOGGING=false
 PROMETHEUS_DISABLE_COLLECT=false
+PROMETHEUS_METRICS_PATH=/prometheus/metrics
 WEBHOOK_ENABLE_SYNC_MODE=false
 WEBHOOK_ALLOW_LIST=
 WEBHOOK_DENY_LIST=
@@ -143,6 +144,7 @@ run: ## Start a Gotenberg container
 	--prometheus-collect-interval=$(PROMETHEUS_COLLECT_INTERVAL) \
 	--prometheus-disable-route-logging=$(PROMETHEUS_DISABLE_ROUTE_LOGGING) \
 	--prometheus-disable-collect=$(PROMETHEUS_DISABLE_COLLECT) \
+	--prometheus-metrics-path=$(PROMETHEUS_METRICS_PATH) \
 	--webhook-enable-sync-mode="$(WEBHOOK_ENABLE_SYNC_MODE)" \
 	--webhook-allow-list="$(WEBHOOK_ALLOW_LIST)" \
 	--webhook-deny-list="$(WEBHOOK_DENY_LIST)" \

pkg/modules/prometheus/prometheus.go

@@ -27,6 +27,7 @@ type Prometheus struct {
 	interval            time.Duration
 	disableRouteLogging bool
 	disableCollect      bool
+	metricsPath         string
 
 	metrics  []gotenberg.Metric
 	registry *prometheus.Registry
@@ -42,6 +43,7 @@ func (mod *Prometheus) Descriptor() gotenberg.ModuleDescriptor {
 			fs.Duration("prometheus-collect-interval", time.Duration(1)*time.Second, "Set the interval for collecting modules' metrics")
 			fs.Bool("prometheus-disable-route-logging", false, "Disable the route logging")
 			fs.Bool("prometheus-disable-collect", false, "Disable the collect of metrics")
+			fs.String("prometheus-metrics-path", "/prometheus/metrics", "Path for Prometheus metrics endpoint")
 
 			return fs
 		}(),
@@ -56,6 +58,7 @@ func (mod *Prometheus) Provision(ctx *gotenberg.Context) error {
 	mod.interval = flags.MustDuration("prometheus-collect-interval")
 	mod.disableRouteLogging = flags.MustBool("prometheus-disable-route-logging")
 	mod.disableCollect = flags.MustBool("prometheus-disable-collect")
+	mod.metricsPath = flags.MustString("prometheus-metrics-path")
 
 	if mod.disableCollect {
 		// Exit early.
@@ -98,6 +101,10 @@ func (mod *Prometheus) Validate() error {
 		return errors.New("namespace must not be empty")
 	}
 
+	if mod.metricsPath == "" {
+		return errors.New("metrics path cannot be empty")
+	}
+
 	metricsMap := make(map[string]string, len(mod.metrics))
 
 	for _, metric := range mod.metrics {
@@ -171,7 +178,7 @@ func (mod *Prometheus) Routes() ([]api.Route, error) {
 	return []api.Route{
 		{
 			Method:         http.MethodGet,
-			Path:           "/prometheus/metrics",
+			Path:           mod.metricsPath,
 			DisableLogging: mod.disableRouteLogging,
 			Handler: echo.WrapHandler(
 				promhttp.HandlerFor(mod.registry, promhttp.HandlerOpts{}),

test/integration/features/debug.feature

@@ -109,6 +109,7 @@ Feature: /debug
           "prometheus-disable-collect": "false",
           "prometheus-disable-route-logging": "false",
           "prometheus-namespace": "gotenberg",
+          "prometheus-metrics-path": "/prometheus/metrics",
           "webhook-allow-list": "",
           "webhook-client-timeout": "30s",
           "webhook-deny-list": "",

test/integration/features/prometheus_metrics.feature

@@ -29,6 +29,31 @@ Feature: /prometheus/metrics
     Then the Gotenberg container should log the following entries:
       | "path":"/prometheus/metrics" |
 
+  Scenario: GET /custom/metrics (Custom Metrics Path)
+    Given I have a Gotenberg container with the following environment variable(s):
+      | PROMETHEUS_METRICS_PATH | /custom/metrics |
+    When I make a "GET" request to Gotenberg at the "/custom/metrics" endpoint
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "text/plain; version=0.0.4; charset=utf-8; escaping=underscores"
+    Then the response body should match string:
+      """
+      # HELP gotenberg_chromium_requests_queue_size Current number of Chromium conversion requests waiting to be treated.
+      # TYPE gotenberg_chromium_requests_queue_size gauge
+      gotenberg_chromium_requests_queue_size 0
+      # HELP gotenberg_chromium_restarts_count Current number of Chromium restarts.
+      # TYPE gotenberg_chromium_restarts_count gauge
+      gotenberg_chromium_restarts_count 0
+      # HELP gotenberg_libreoffice_requests_queue_size Current number of LibreOffice conversion requests waiting to be treated.
+      # TYPE gotenberg_libreoffice_requests_queue_size gauge
+      gotenberg_libreoffice_requests_queue_size 0
+      # HELP gotenberg_libreoffice_restarts_count Current number of LibreOffice restarts.
+      # TYPE gotenberg_libreoffice_restarts_count gauge
+      gotenberg_libreoffice_restarts_count 0
+
+      """
+    Then the Gotenberg container should log the following entries:
+      | "path":"/custom/metrics" |
+
   Scenario: GET /prometheus/metrics (Custom Namespace)
     Given I have a Gotenberg container with the following environment variable(s):
       | PROMETHEUS_NAMESPACE | foo |