feat: Prometheus /metrics endpoint — Phase 5 -> 6/8

- metrics.v: GET /metrics au format OpenMetrics (gauges + counters)
- server.v: route /metrics, Stats.http_polls counter, increment in poll loop
- metrics_test.v: test du endpoint metrics
- ROADMAP: Phase 5 6/8 (Prometheus done)

docs/ROADMAP.md

@@ -106,7 +106,7 @@ Objectif : un seul binaire, une seule commande pour installer/désinstaller le s
 
 **Sortie** : `ntfy-bridge --install-service` fonctionne sur Windows 10+, Debian 11+, Alpine 3.18+, Raspberry Pi OS (arm64). ✅
 
-## Phase 5 : Futures idées — v0.5.0+ (4/8)
+## Phase 5 : Futures idées — v0.5.0+ (6/8)
 
 - [x] Web UI minimale — Dashboard avec statuts, historique, API endpoints
 - [x] Filtres avancés — Expressions conditionnelles par source
@@ -116,20 +116,17 @@ Objectif : un seul binaire, une seule commande pour installer/désinstaller le s
       - match_source: "docker"
         match_name: "test-*"
         action: drop
-      - match_source: "gitea"
-        action: set_priority
-        value: "5"
   ```
-  - Actions: `drop`, `set_priority:N`, `add_tag:X`
-  - Wildcard `*` supporté dans `match_name`
 - [x] Notifications structurées — Support des actions Ntfy (boutons click)
   - Champ `click_url` pour ouvrir une URL au clic
   - Champ `actions` pour boutons d'action (view, broadcast, http)
-- [ ] Intégration Prometheus — Métriques exposées au format OpenMetrics
+- [x] Intégration Prometheus — Métriques exposées au format OpenMetrics
+  - Endpoint `GET /metrics` : gauges (uptime, poll_state, silence) + counters (notifications, errors, http_polls)
+  - Format compatible Prometheus/Grafana
 - [x] Webhook sortant — Forwarder les événements vers Slack, Discord, JSON
-  ```yaml
-  outgoing:
-    webhooks:
+- [ ] Support multi-utilisateurs — ACLs par webhook_path
+- [x] Fichier d'état — Persistance de l'état up/down des health checks
+- [ ] Plugin system — Sources customisables via dll/.so
       - url: "https://hooks.slack.com/..."
         format: slack
       - url: "https://discord.com/api/webhooks/..."
@@ -169,4 +166,4 @@ Ces features ont été ajoutées en cours de route :
 | v0.3.0 | ✅ Terminé | Robustesse, HMAC, retry, graceful shutdown, SIGHUP reload, tests |
 | v0.4.0 | ✅ Terminé | Templates, silence, grouping, HMAC global, CI/CD |
 | v0.4.5 | ✅ Terminé | Déploiement multi-plateforme : --install-service, Windows, systemd, openrc, Docker, install scripts |
-| v0.5.0+ | 🚧 4/8 | Dashboard, filtres avancés, actions Ntfy, outgoing webhooks, state file — manque Prometheus, multi-user, plugins |
+| v0.5.0+ | 🚧 6/8 | Dashboard, filtres, actions Ntfy, Prometheus, outgoing webhooks, state file — manque multi-user, plugins |

metrics.v

@@ -0,0 +1,71 @@
+module main
+
+import net.http
+import time
+
+// metrics_response returns a Prometheus / OpenMetrics formatted response.
+fn (mut app App) metrics_response() http.Response {
+	mut lines := []string{}
+
+	// HELP/TYPE headers
+	lines << '# HELP ntfy_bridge_uptime_seconds Seconds since the bridge started.'
+	lines << '# TYPE ntfy_bridge_uptime_seconds gauge'
+	lines << 'ntfy_bridge_uptime_seconds ${app.uptime_seconds()}'
+
+	lines << '# HELP ntfy_bridge_notifications_total Total notifications sent (all sources).'
+	lines << '# TYPE ntfy_bridge_notifications_total counter'
+	lines << 'ntfy_bridge_notifications_total ${app.stats.total_notifications}'
+
+	lines << '# HELP ntfy_bridge_errors_total Total publish errors.'
+	lines << '# TYPE ntfy_bridge_errors_total counter'
+	lines << 'ntfy_bridge_errors_total ${app.stats.errors}'
+
+	lines << '# HELP ntfy_bridge_notifications_by_source Notifications by source type.'
+	lines << '# TYPE ntfy_bridge_notifications_by_source counter'
+	for source, count in app.stats.by_source {
+		lines << 'ntfy_bridge_notifications_by_source{source="${source}"} ${count}'
+	}
+
+	lines << '# HELP ntfy_bridge_poll_up Health check polling status (1=up, 0=down).'
+	lines << '# TYPE ntfy_bridge_poll_up gauge'
+	for url, is_up in app.poll_state {
+		val := if is_up { '1' } else { '0' }
+		safe_url := url.replace('"', '\\"')
+		lines << 'ntfy_bridge_poll_up{url="${safe_url}"} ${val}'
+	}
+
+	lines << '# HELP ntfy_bridge_http_polls_total Total HTTP poll checks performed.'
+	lines << '# TYPE ntfy_bridge_http_polls_total counter'
+	lines << 'ntfy_bridge_http_polls_total ${app.stats.http_polls}'
+
+	lines << '# HELP ntfy_bridge_silence_active Whether notification silence is active.'
+	lines << '# TYPE ntfy_bridge_silence_active gauge'
+	now := time.now()
+	silence_val := if now.unix() < app.silence_until.unix() { '1' } else { '0' }
+	lines << 'ntfy_bridge_silence_active ${silence_val}'
+
+	lines << '# HELP ntfy_bridge_silence_remaining_seconds Seconds remaining in current silence.'
+	lines << '# TYPE ntfy_bridge_silence_remaining_seconds gauge'
+	remaining := if time.now() < app.silence_until {
+		(app.silence_until - time.now()) / time.second
+	} else {
+		0
+	}
+	lines << 'ntfy_bridge_silence_remaining_seconds ${remaining}'
+
+	// EOF
+	lines << '# EOF'
+
+	return http.Response{
+		status_code: 200
+		header:      http.Header{}
+		body:        lines.join('\n') + '\n'
+	}
+}
+
+// uptime_seconds returns the number of seconds since the server started.
+fn (app App) uptime_seconds() i64 {
+	now := time.now()
+	diff := now.unix() - app.start_time.unix()
+	return i64(diff)
+}

metrics_test.v

@@ -0,0 +1,28 @@
+module main
+
+fn test_metrics_keys() {
+	mut app := App{
+		logger: new_logger(.info, false)
+		cfg: Config{
+			filters: FilterConfig{}
+			outgoing: OutgoingConfig{}
+			state: StateConfig{}
+		}
+		poll_state: map[string]bool{}
+	}
+	app.poll_state['http://example.com'] = true
+	app.poll_state['http://down.com'] = false
+	app.stats.total_notifications = 42
+	app.stats.errors = 3
+	app.stats.by_source['docker'] = 10
+
+	resp := app.metrics_response()
+	body := resp.body
+
+	assert body.contains('ntfy_bridge_uptime_seconds')
+	assert body.contains('ntfy_bridge_notifications_total 42')
+	assert body.contains('ntfy_bridge_errors_total 3')
+	assert body.contains('ntfy_bridge_silence_active')
+	assert body.contains('ntfy_bridge_http_polls_total')
+	assert body.contains('# EOF')
+}

server.v

@@ -15,9 +15,10 @@ pub struct Stats {
 pub mut:
 	total_notifications int
 	errors              int
+	http_polls          int // v0.5: total HTTP poll checks
 	by_source           map[string]int
+	start_time          time.Time
 }
-
 pub struct App {
 pub mut:
 	cfg              Config
@@ -190,6 +191,9 @@ pub fn (mut app App) handle(req http.Request) http.Response {
 			if req.url == '/api/silence' {
 				return app.silence_status_response()
 			}
+			if req.url == '/metrics' {
+				return app.metrics_response()
+			}
 		}
 		.post {
 			if req.url.starts_with('/api/silence') {
@@ -409,6 +413,7 @@ fn (mut app App) http_poll_loop() {
 		}
 		for src in app.cfg.sources.http_poll {
 			for check in src.checks {
+				app.stats.http_polls++
 				app.run_http_check(check)
 			}
 		}