feat(deploy): add Prometheus + Grafana observability stack (closes #11)

deploy/truenas/core/docker-compose.yml

@@ -1,13 +1,12 @@
-# Dragon Fork datarhei Core — M2 deployment with WebRTC egress.
+# Dragon Fork datarhei Core — v0.2 deployment with WebRTC egress and observability.
 #
-# This replaces the M1 webrtc-poc stack. It runs the real root Core
-# binary with the WebRTC subsystem wired into the restream manager, so
-# every process whose config has `webrtc.enabled=true` will have its
-# output fanned out to WHEP subscribers automatically.
+# This replaces the M2 stack. Adds Prometheus and Grafana containers so the
+# operator can answer "is WebRTC healthy right now?" from a single dashboard
+# without tailing logs or hitting the API.
 #
-# Host networking is required for the same reason as M1: ICE encodes
-# host:port pairs into SDP candidates, and bridge-mode port mapping
-# breaks that.
+# Host networking is required for WebRTC ICE (see deploy/truenas/docker-compose.yml).
+# Prometheus and Grafana sit on a bridge network (dragonfork-mon) and reach
+# Core via host.docker.internal:CORE_HTTP_PORT.
 #
 # Copy this file to /mnt/NVME/Docker/dragonfork-core/ alongside a .env:
 #
@@ -15,6 +14,7 @@
 #   API_AUTH_USERNAME=admin
 #   API_AUTH_PASSWORD=change-me-please
 #   API_AUTH_JWT_SECRET=<32+ random bytes, base64>
+#   GRAFANA_ADMIN_PASSWORD=$(openssl rand -base64 24)
 #
 # Then:
 #   docker compose up -d --build
@@ -39,23 +39,13 @@ services:
       # --- WebRTC egress ---
       CORE_WEBRTC_ENABLE: "true"
       CORE_WEBRTC_PUBLIC_IP: "${PUBLIC_IP:?set in .env}"
-      # Leave NAT1To1_IPS empty unless you need multiple advertised IPs.
-      # CORE_WEBRTC_NAT_1_TO_1_IPS: "10.0.0.25 203.0.113.10"
 
-      # --- RTMP / RTMPS / SRT / TLS port overrides ---
-      # Default Datarhei ports (1935, 1936, 6000, 8181) are common
-      # and frequently collide with an existing upstream datarhei/
-      # restreamer container or other RTMP servers on the same host.
-      # Pull these out of .env so operators can remap without editing
-      # this file. Empty strings keep the upstream defaults.
+      # --- Port overrides ---
       CORE_RTMP_ADDRESS: "${CORE_RTMP_ADDRESS:-:1935}"
       CORE_RTMP_ADDRESS_TLS: "${CORE_RTMP_ADDRESS_TLS:-:1936}"
       CORE_SRT_ADDRESS: "${CORE_SRT_ADDRESS:-:6000}"
       CORE_TLS_ADDRESS: "${CORE_TLS_ADDRESS:-:8181}"
 
-      # --- Storage ---
-      # Let the volumes below provide durable paths; defaults are fine.
-
       # --- Logging ---
       CORE_LOG_LEVEL: "${LOG_LEVEL:-info}"
 
@@ -63,5 +53,47 @@ services:
       - ./config:/core/config
       - ./data:/core/data
 
-    # No ports: host networking exposes whatever the process binds.
-    # The WHEP endpoint lives at /api/v3/whep/:id on CORE_HTTP_PORT.
+  prom:
+    image: prom/prometheus:v2.55.0
+    container_name: dragonfork-prom
+    restart: unless-stopped
+    networks: [dragonfork-mon]
+    extra_hosts:
+      - "host.docker.internal:host-gateway"
+    volumes:
+      - ./prom/prometheus.yml:/etc/prometheus/prometheus.yml:ro
+      - ./prom/rules:/etc/prometheus/rules:ro
+      - prom-data:/prometheus
+    command:
+      - --config.file=/etc/prometheus/prometheus.yml
+      - --storage.tsdb.retention.time=${PROM_RETENTION:-15d}
+      - --storage.tsdb.path=/prometheus
+      - --web.console.libraries=/usr/share/prometheus/console_libraries
+      - --web.console.templates=/usr/share/prometheus/consoles
+    ports:
+      - "${PROM_PORT:-9090}:9090"
+
+  grafana:
+    image: grafana/grafana-oss:11.3.0
+    container_name: dragonfork-grafana
+    restart: unless-stopped
+    networks: [dragonfork-mon]
+    depends_on: [prom]
+    environment:
+      GF_SECURITY_ADMIN_PASSWORD: "${GRAFANA_ADMIN_PASSWORD:?set in .env}"
+      GF_USERS_ALLOW_SIGN_UP: "false"
+      GF_AUTH_ANONYMOUS_ENABLED: "false"
+    volumes:
+      - ./grafana/provisioning:/etc/grafana/provisioning:ro
+      - ./grafana/dashboards:/var/lib/grafana/dashboards:ro
+      - grafana-data:/var/lib/grafana
+    ports:
+      - "${GRAFANA_PORT:-3000}:3000"
+
+networks:
+  dragonfork-mon:
+    driver: bridge
+
+volumes:
+  prom-data:
+  grafana-data: