version: "3.8"

# Production Docker Swarm stack for stratoflights-predictor.
#
# Deploy:  TAG=v1.0.0 docker stack deploy -c docker-compose.swarm.yml --with-registry-auth predictor
# (or import via Swarmpit; the CI pipeline deploys it through the Swarmpit API)
#
# Storage & placement (see DEPLOYMENT.md):
#   * The wind dataset (~8.9 GiB) lives on NODE-LOCAL disk — never NFS. To keep
#     the number of copies bounded, the service is pinned to nodes labelled
#     `predictor.data=true`; label at most two such nodes. Each carries one copy.
#   * Replicas are spread one-per-node by default (redundancy + load balancing);
#     scaling to multiple replicas per node is safe because they share the
#     node-local volume and coordinate downloads via an flock (no duplicate fetch).
#
# The predictor is an internal backend: it has no public Traefik router. The
# Django API gateway and Prometheus reach it over the shared `stratoflights-net`
# overlay by the alias `predictor`.

services:
  predictor:
    image: git.intra.yksa.space/web/predictor:${TAG:-latest}
    networks:
      stratoflights-net:
        aliases:
          - predictor
    environment:
      PREDICTOR_DATA_DIR: /data
      PREDICTOR_ELEVATION_DATASET: /srv/ruaumoko-dataset
      PREDICTOR_SOURCE: ${PREDICTOR_SOURCE:-gfs-0p50-3h}
      PREDICTOR_DOWNLOAD_PARALLEL: ${PREDICTOR_DOWNLOAD_PARALLEL:-16}
      PREDICTOR_UPDATE_INTERVAL: 6h
      PREDICTOR_DATASET_TTL: 48h
      PREDICTOR_METRICS_ENABLED: "true"
      PREDICTOR_METRICS_PATH: /metrics
      PREDICTOR_LOG_LEVEL: info
    volumes:
      # Node-local storage. Provision these directories on each labelled node
      # (chown to 65532:65532 — see DEPLOYMENT.md). NOT a shared/NFS volume.
      - type: bind
        source: /srv/predictor/data
        target: /data
      - type: bind
        source: /srv/predictor/elevation
        target: /srv/ruaumoko-dataset
        read_only: true
    healthcheck:
      test: ["CMD", "/predictor", "-healthcheck"]
      interval: 30s
      timeout: 5s
      retries: 3
      start_period: 120s
    logging:
      driver: json-file
      options:
        max-size: "10m"
        max-file: "3"
    deploy:
      mode: replicated
      replicas: 2
      placement:
        max_replicas_per_node: 2
        constraints:
          - node.labels.predictor.data == true
        preferences:
          # Spread across the labelled nodes so the two default replicas land
          # on different hosts (redundancy across both dataset copies).
          - spread: node.labels.predictor.data
      update_config:
        parallelism: 1
        delay: 15s
        order: start-first
        failure_action: rollback
      rollback_config:
        parallelism: 1
        order: stop-first
      restart_policy:
        condition: on-failure
        delay: 5s
        max_attempts: 3
      resources:
        limits:
          memory: 3072M
        reservations:
          memory: 512M
      labels:
        # Prometheus Swarm service-discovery hints (adjust to your SD relabel rules).
        - "prometheus.scrape=true"
        - "prometheus.port=8080"
        - "prometheus.path=/metrics"
        # Let Swarmpit auto-redeploy when a new :latest (or pinned TAG) is pushed.
        - "swarmpit.service.deployment.autoredeploy=true"

networks:
  # Shared overlay also joined by the API gateway and Prometheus.
  # Create once:  docker network create -d overlay --attachable stratoflights-net
  stratoflights-net:
    external: true