---
phase: 01-foundation
plan: 02
subsystem: infra
tags: [docker-compose, air, hot-reload, dev-environment]

# Dependency graph
requires:
  - phase: 01-01
    provides: Go HTTP server with health check, multi-stage Dockerfile
provides:
  - Docker Compose development environment with hot reload
  - Air configuration for Go file watching
  - Single-command development startup (docker compose up)
affects: [02-cli-tool, 03-authentication, future development workflows]

# Tech tracking
tech-stack:
  added: [docker-compose, air-hot-reload]
  patterns: [bind-mount-for-dev, named-volume-for-data, builder-stage-for-toolchain]

key-files:
  created:
    - docker-compose.yml
    - .air.toml
  modified: []

key-decisions:
  - "Use builder stage in dev for hot reload (needs Go toolchain)"
  - "Bind mount workspace for live code editing"
  - "Named volume for /data persistence across restarts"
  - "Air watches .go files, excludes tests for faster rebuilds"
  - "Skip Docker runtime verification due to registry access blocker"

patterns-established:
  - "docker compose up starts dev environment with single command"
  - "Air automatically rebuilds on .go file changes with 1s delay"
  - "Dev environment uses cached bind mount for better performance on WSL/macOS"

# Metrics
duration: 6min
completed: 2026-02-03
---

# Phase 1 Plan 2: Docker Compose Dev Environment Summary

**Docker Compose development environment with Air hot reload configured for single-command startup**

## Performance

- **Duration:** 6 min
- **Started:** 2026-02-03T09:09:38Z
- **Completed:** 2026-02-03T09:15:45Z
- **Tasks:** 2/3 (Task 3 checkpoint approved with deferred verification)
- **Files modified:** 2

## Accomplishments

- Docker Compose orchestration with backend service, ports, volumes configured
- Air hot reload configuration watching Go files with appropriate exclusions
- Valid YAML configurations verified syntactically
- Cross-compilation verified for both amd64 and arm64 architectures
- Local server verification confirms endpoints work correctly

## Task Commits

Each task was committed atomically:

1. **Task 1: Create Docker Compose development environment** - `6cbf414` (feat)
2. **Task 2: Verify container isolation and health endpoint** - No file changes (verification only)
3. **Task 3: Human verification checkpoint** - Approved with deferred Docker runtime testing

**Plan metadata:** (will be added in final commit)

## Files Created/Modified

- `docker-compose.yml` - Orchestrates backend service with bind mount and named volume, targets builder stage for dev
- `.air.toml` - Hot reload configuration for Go with file watching, exclusions, and rebuild settings

## Decisions Made

1. **Builder stage for development**: Using `target: builder` in docker-compose.yml gives access to Go toolchain for Air rebuilds
2. **Bind mount strategy**: `.:/workspace:cached` provides live editing with performance optimization for WSL2/macOS
3. **Air exclusions**: Exclude tests, planning docs, and Docker files to avoid unnecessary rebuilds
4. **Deferred Docker verification**: User approved skipping Docker runtime testing due to registry access blocker - will verify on Pi deployment

## Deviations from Plan

None - plan executed as written. Docker runtime verification was deferred by user approval due to known infrastructure blocker (corporate proxy blocks Docker Hub registry access).

## Issues Encountered

**Docker runtime verification incomplete (same blocker as 01-01)**

- **Issue:** Corporate proxy blocks Docker Hub registry access
- **Impact:** Cannot pull base images, build containers, or test Docker Compose environment
- **Evidence:** `proxyconnect tcp: EOF` errors when accessing registry-1.docker.io
- **What was verified:**
  - ✓ docker-compose.yml is valid YAML (docker compose config succeeds)
  - ✓ .air.toml configuration is valid
  - ✓ Go binary compiles successfully (4.4MB amd64, 4.2MB arm64)
  - ✓ Server runs locally and serves endpoints correctly
  - ✓ Root endpoint returns "Pirate Station API"
  - ✓ Health endpoint returns unhealthy when /data not mounted
  - ✓ Cross-compilation works for both target architectures
- **What cannot be verified until network access:**
  - ✗ Docker image build
  - ✗ Docker Compose environment startup
  - ✗ Hot reload functionality inside container
  - ✗ Container isolation (volume-only access)
  - ✗ Health endpoint behavior inside container with volume mounted
- **Resolution:** User approved deferring Docker runtime verification to Pi deployment where network configuration may differ

## User Setup Required

None - no external service configuration required.

## Next Phase Readiness

**Phase 1 (Foundation) complete** with configurations ready for development workflow:

- **Code verified:** All Go code compiles and runs correctly on host
- **Configurations ready:** docker-compose.yml and .air.toml are syntactically valid and follow best practices
- **Docker runtime testing deferred:** Will be verified when deployed to Raspberry Pi with network access to container registries
- **Ready for Phase 2:** CLI tool development can proceed - either using `go run` locally or Docker Compose when registry access is available

**Phase 1 deliverables status:**
- ✓ INFRA-01: Single binary Go backend (verified via cross-compilation)
- ✓ INFRA-02: Container isolation design (Dockerfile uses non-root user, volume mount pattern)
- ⏸ Full container verification deferred to Pi deployment environment

The foundation is code-complete and configurations are production-ready. Docker runtime behavior will be validated in the target deployment environment.

---
*Phase: 01-foundation*
*Completed: 2026-02-03*