Gitea Act Runner: DinD stack with cache + parallel jobs

Stable docker-compose setup for building Rust projects on Gitea Actions.
DinD-isolated daemon, built-in cache server, capacity=4 parallel jobs,
healthcheck-gated startup. Portable to other build machines via .env.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HU4wDwdydNZpR3YkMiYYy8

docker-compose.yml

@@ -0,0 +1,51 @@
+services:
+  # Isolated Docker daemon for the runner's job containers.
+  # Keeps the host Docker clean and gives reliable cache networking.
+  dind:
+    image: docker:27-dind
+    container_name: gitea-runner-dind
+    privileged: true
+    restart: unless-stopped
+    command: ["dockerd", "--host=tcp://0.0.0.0:2375", "--host=unix:///var/run/docker.sock", "--tls=false"]
+    environment:
+      DOCKER_TLS_CERTDIR: ""
+    networks:
+      - runner
+    volumes:
+      # Persist pulled job images + docker layer cache => fast Rust rebuilds.
+      - dind-storage:/var/lib/docker
+    healthcheck:
+      test: ["CMD", "docker", "info"]
+      interval: 5s
+      timeout: 3s
+      retries: 10
+      start_period: 10s
+
+  runner:
+    image: docker.io/gitea/act_runner:nightly
+    container_name: gitea-runner-wsl
+    restart: unless-stopped
+    depends_on:
+      dind:
+        condition: service_healthy
+    networks:
+      - runner
+    environment:
+      GITEA_INSTANCE_URL: ${GITEA_INSTANCE_URL}
+      GITEA_RUNNER_REGISTRATION_TOKEN: ${GITEA_RUNNER_REGISTRATION_TOKEN}
+      GITEA_RUNNER_NAME: ${GITEA_RUNNER_NAME}
+      GITEA_RUNNER_LABELS: ""
+      # Point the runner at the DinD daemon.
+      DOCKER_HOST: tcp://dind:2375
+      CONFIG_FILE: /config.yaml
+    volumes:
+      - ./config.yaml:/config.yaml:ro
+      # Persist runner registration so it survives restarts.
+      - runner-data:/data
+
+networks:
+  runner:
+
+volumes:
+  dind-storage:
+  runner-data: