feat(server): ability to disable metrics

src/server/api_metrics.v

@@ -3,14 +3,17 @@ module server
 import metrics
 import web
 
-['/api/v1/metrics'; get]
+// v1_metrics serves a Prometheus-compatible metrics endpoint.
+['/api/v1/metrics'; get; markused]
 fn (mut app App) v1_metrics() web.Result {
+	if !app.conf.collect_metrics {
+		return app.status(.not_found)
+	}
+
 	mut exporter := metrics.new_prometheus_exporter([0.01, 0.05, 0.1, 0.5, 1, 100])
 	exporter.load(app.collector)
-	
+
 	// TODO stream to connection instead
-	body := exporter.export_to_string() or {
-		return app.status(.internal_server_error)
-	}
+	body := exporter.export_to_string() or { return app.status(.internal_server_error) }
 	return app.body(.ok, 'text/plain', body)
 }

src/server/cli.v

@@ -15,6 +15,7 @@ pub:
 	base_image           string = 'archlinux:base-devel'
 	max_log_age          int    [empty_default]
 	log_removal_schedule string = '0 0'
+	collect_metrics      bool   [empty_default]
 }
 
 // cmd returns the cli submodule that handles starting the server

src/server/server.v

@@ -101,14 +101,20 @@ pub fn server(conf Config) ! {
 		util.exit_with_message(1, 'Failed to initialize database: $err.msg()')
 	}
 
+	collector := if conf.collect_metrics {
+		&metrics.MetricsCollector(metrics.new_default_collector())
+	} else {
+		&metrics.MetricsCollector(metrics.new_null_collector())
+	}
+
 	mut app := &App{
 		logger: logger
 		api_key: conf.api_key
 		conf: conf
 		repo: repo
 		db: db
+		collector: collector
 		job_queue: build.new_job_queue(global_ce, conf.base_image)
-		collector: metrics.new_default_collector()
 	}
 	app.init_job_queue() or {
 		util.exit_with_message(1, 'Failed to inialize job queue: $err.msg()')