# Observability stack — Grafana LGTM + GlitchTip
#
# Requires the main stack to be running first:
#   docker compose up -d                                    # creates archiv-net
#   docker compose -f docker-compose.observability.yml up -d
#
# To validate without starting:
#   docker compose -f docker-compose.observability.yml config

services:

  # --- Metrics: Prometheus ---

  prometheus:
    image: prom/prometheus:v3.4.0
    container_name: obs-prometheus
    restart: unless-stopped
    volumes:
      - ./infra/observability/prometheus/prometheus.yml:/etc/prometheus/prometheus.yml:ro
      - prometheus_data:/prometheus
    command:
      - '--config.file=/etc/prometheus/prometheus.yml'
      - '--storage.tsdb.path=/prometheus'
      - '--storage.tsdb.retention.time=30d'
      - '--web.enable-lifecycle'
    ports:
      - "127.0.0.1:${PORT_PROMETHEUS:-9090}:9090"
    healthcheck:
      test: ["CMD", "wget", "-qO-", "http://localhost:9090/-/healthy"]
      interval: 30s
      timeout: 5s
      retries: 3
    networks:
      - archiv-net
      - obs-net

  node-exporter:
    image: prom/node-exporter:v1.9.0
    container_name: obs-node-exporter
    restart: unless-stopped
    # pid: host — required for process-level CPU/memory metrics; cgroup isolation applies
    pid: host
    volumes:
      - /proc:/host/proc:ro
      - /sys:/host/sys:ro
      - /:/rootfs:ro
    command:
      - '--path.procfs=/host/proc'
      - '--path.sysfs=/host/sys'
      # $$ is YAML Compose escaping for a literal $ in the regex alternation
      - '--collector.filesystem.ignored-mount-points=^/(sys|proc|dev|host|etc)($$|/)'
    expose:
      - "9100"
    networks:
      - obs-net

  cadvisor:
    image: gcr.io/cadvisor/cadvisor:v0.52.1
    container_name: obs-cadvisor
    restart: unless-stopped
    # privileged: true — required for cgroup and namespace metrics, see cAdvisor docs.
    # Accepted risk: cAdvisor is pinned, on Renovate, and not exposed outside obs-net.
    privileged: true
    volumes:
      - /:/rootfs:ro
      # /var/run/docker.sock mounted read-only — sufficient for container metadata discovery
      - /var/run/docker.sock:/var/run/docker.sock:ro
      - /sys:/sys:ro
      - /var/lib/docker:/var/lib/docker:ro
    expose:
      - "8080"
    networks:
      - obs-net

  # --- Logs: Loki + Promtail ---

  loki:
    image: grafana/loki:3.4.2
    container_name: obs-loki
    restart: unless-stopped
    volumes:
      - ./infra/observability/loki/loki-config.yml:/etc/loki/loki-config.yml:ro
      - loki_data:/loki
    command: -config.file=/etc/loki/loki-config.yml
    expose:
      - "3100"
    healthcheck:
      test: ["CMD-SHELL", "wget -qO- http://localhost:3100/ready | grep -q ready || exit 1"]
      interval: 10s
      timeout: 5s
      retries: 5
      start_period: 30s
    networks:
      - obs-net

  promtail:
    image: grafana/promtail:3.4.2
    container_name: obs-promtail
    restart: unless-stopped
    volumes:
      - ./infra/observability/promtail/promtail-config.yml:/etc/promtail/promtail-config.yml:ro
      - /var/lib/docker/containers:/var/lib/docker/containers:ro
      # :ro restricts file-system access but NOT Docker API permissions — a compromised Promtail has full daemon access. Accepted risk on single-operator self-hosted archive.
      - /var/run/docker.sock:/var/run/docker.sock:ro
      - promtail_positions:/tmp  # persists positions.yaml across restarts — avoids duplicate log ingestion
    command: -config.file=/etc/promtail/promtail-config.yml
    networks:
      - archiv-net  # label discovery from application containers via Docker socket
      - obs-net     # log shipping to Loki
    depends_on:
      loki:
        condition: service_healthy

  # --- Traces: Tempo ---

  tempo:
    image: grafana/tempo:2.7.2
    container_name: obs-tempo
    restart: unless-stopped
    volumes:
      - ./infra/observability/tempo/tempo.yml:/etc/tempo.yml:ro
      - tempo_data:/var/tempo
    command: -config.file=/etc/tempo.yml
    expose:
      - "3200"   # Grafana queries Tempo on this port (obs-net only)
      - "4317"   # OTLP gRPC — backend sends traces here (archiv-net)
      - "4318"   # OTLP HTTP — alternative transport (archiv-net)
    healthcheck:
      test: ["CMD-SHELL", "wget -qO- http://localhost:3200/ready | grep -q ready || exit 1"]
      interval: 10s
      timeout: 5s
      retries: 5
      start_period: 15s
    networks:
      - archiv-net   # backend (archive-backend) reaches tempo:4317 over this network
      - obs-net      # Grafana reaches tempo:3200 over this network

  # --- Dashboards: Grafana ---

  obs-grafana:
    image: grafana/grafana-oss:11.6.1
    container_name: obs-grafana
    restart: unless-stopped
    ports:
      - "127.0.0.1:${PORT_GRAFANA:-3001}:3000"
    environment:
      GF_SECURITY_ADMIN_PASSWORD: ${GRAFANA_ADMIN_PASSWORD:-changeme}
      GF_USERS_ALLOW_SIGN_UP: "false"
    volumes:
      - grafana_data:/var/lib/grafana
      - ./infra/observability/grafana/provisioning:/etc/grafana/provisioning:ro
    depends_on:
      - prometheus
      - loki
      - tempo
    networks:
      - obs-net

  # --- Error Tracking: GlitchTip ---
  #   glitchtip: (see future issue)

networks:
  # Shared network created by the main docker-compose.yml.
  # The observability stack joins as a peer so Prometheus can scrape
  # archive-backend by container name. The observability stack must NOT
  # attempt to create this network — it will fail with a clear error if
  # the main stack is not running yet.
  archiv-net:
    external: true

  # Internal network for observability-service-to-service traffic
  # (e.g. Grafana → Prometheus, Grafana → Loki, Grafana → Tempo).
  obs-net:
    driver: bridge

volumes:
  prometheus_data:
  loki_data:
  promtail_positions:
  tempo_data:
  grafana_data:
  glitchtip_data: