foxhunt/foxhunt-deploy/DOCKER_BUILD_MILESTONE2.md

Milestone 2: Docker Build Implementation

Status: ✅ COMPLETE Date: 2025-11-02 Time: ~45 minutes

Summary

Implemented Docker build and push functionality for the foxhunt-deploy CLI. The implementation uses std::process::Command to execute Docker commands with real-time output streaming and visual progress indicators.

Implementation Details

Module Structure

src/docker/
├── mod.rs         # Docker verification utilities
├── build.rs       # Docker build implementation
└── push.rs        # Docker push implementation

Key Components

1. Docker Module (src/docker/mod.rs)

Functions:

• verify_docker_available() - Validates Docker installation and daemon status
• image_exists(tag) - Checks if a Docker image exists locally

Features:

• Uses which docker to verify Docker is installed
• Checks Docker daemon status via docker version
• Provides clear error messages for common issues

2. Build Module (src/docker/build.rs)

Main Types:

• DockerBuildOptions - Builder pattern for build configuration
• build_image() - Main build function with streaming output

Features:

• Builder pattern API for flexible configuration
• Real-time output streaming with BufReader
• Progress spinner using indicatif crate
• Validates Dockerfile and build context existence
• Captures and returns image ID after successful build
• Detailed error messages with stderr output

Options:

• tag - Docker image tag (e.g., "jgrusewski/foxhunt:latest")
• dockerfile - Path to Dockerfile (default: "Dockerfile.foxhunt-build")
• context - Build context directory (default: ".")
• no_cache - Disable Docker build cache
• build_args - Additional build arguments (reserved for future use)

3. Push Module (src/docker/push.rs)

Main Functions:

• push_image(tag) - Push image to registry
• check_registry_auth(registry) - Verify registry authentication

Features:

• Validates image exists before pushing
• Real-time progress streaming
• Progress spinner with upload status
• Special handling for authentication errors
• Clear error messages suggesting docker login

Integration

Updated src/cli/build.rs to use the new Docker module:

pub async fn execute(config: &FoxhuntConfig, args: &BuildArgs) -> Result<()> {
    // Step 1: Verify Docker
    docker::verify_docker_available()?;

    // Step 2: Build image
    let full_tag = format!("{}/{}:{}",
        config.docker.registry,
        config.docker.image_name,
        args.tag
    );

    let build_options = DockerBuildOptions::new(full_tag.clone())
        .dockerfile(args.dockerfile.clone())
        .context(args.context.clone())
        .no_cache(args.no_cache);

    let _image_id = docker::build::build_image(&build_options)?;

    // Step 3: Push (unless --no-push)
    if !args.no_push {
        docker::push::push_image(&full_tag)?;
    }

    Ok(())
}

Testing

Unit Tests (5 tests)

Located in:

• src/docker/mod.rs (2 tests)
• src/docker/build.rs (2 tests)
• src/docker/push.rs (1 test)

Coverage:

• ✅ Builder pattern API
• ✅ Default values
• ✅ Docker availability check
• ✅ Image existence check
• ✅ Registry auth check

Integration Tests (14 tests)

Located in tests/docker_integration_tests.rs

Coverage:

• ✅ CLI help output
• ✅ Config validation
• ✅ Command-line arguments
• ✅ Error message format validation
• ✅ Flag recognition (--no-push, --no-cache, etc.)

Test Results:

running 14 tests
test test_build_args_defaults ... ok
test test_build_command_help ... ok
test test_build_error_handling_daemon_not_running ... ok
test test_build_error_handling_no_docker ... ok
test test_build_options_builder_pattern ... ok
test test_build_requires_config ... ok
test test_build_validates_dockerfile_existence ... ok
test test_build_with_custom_context ... ok
test test_build_with_custom_dockerfile ... ok
test test_build_with_custom_tag ... ok
test test_build_with_no_cache_flag ... ok
test test_build_with_no_push_flag ... ok
test test_push_error_handling_image_not_found ... ok
test test_push_error_handling_no_auth ... ok

test result: ok. 14 passed; 0 failed; 0 ignored

Usage Examples

Basic Build (with push)

# Builds and pushes jgrusewski/foxhunt:latest
foxhunt-deploy build

Build with Custom Tag (no push)

# Builds jgrusewski/foxhunt:v1.0.0 without pushing
foxhunt-deploy build --tag v1.0.0 --no-push

Build with Custom Dockerfile

# Use a different Dockerfile
foxhunt-deploy build --dockerfile Dockerfile.custom --no-cache

Build with Custom Context

# Use a different build context
foxhunt-deploy build --context ../parent-dir --tag test

Error Handling

The implementation provides clear, actionable error messages:

Docker Not Installed

Error: Docker is not installed. Please install Docker Desktop or Docker Engine.

Docker Daemon Not Running

Error: Docker daemon is not running. Please start Docker Desktop or Docker service.

Dockerfile Not Found

Error: Dockerfile not found: Dockerfile.foxhunt-build

Build Context Not Found

Error: Build context directory not found: .

Authentication Failed

Error: Docker registry authentication failed. Please run 'docker login' first.

Image Doesn't Exist (for push)

Error: Image 'jgrusewski/foxhunt:latest' does not exist locally. Build it first.

Visual Feedback

The implementation uses indicatif for progress indication:

[1/3] Verifying Docker installation...
ℹ Building Docker image: jgrusewski/foxhunt:latest
ℹ Dockerfile: Dockerfile.foxhunt-build
ℹ Context: .
⠋ Starting Docker build...
[2/3] Building Docker image...
⠙ Step 5/12: RUN cargo build --release
✓ Built image: jgrusewski/foxhunt:latest (sha256:abc123...)
[3/3] Pushing to Docker registry...
⠸ Pushing to registry...
✓ Successfully pushed: jgrusewski/foxhunt:latest
✓ Docker build completed successfully!
ℹ Image: jgrusewski/foxhunt:latest

Design Decisions

1. std::process::Command vs bollard

Choice: std::process::Command Rationale:

• Simpler implementation (no additional dependencies)
• Direct access to Docker CLI features
• Easier debugging (can run same commands manually)
• Better compatibility across Docker versions
• Minimal overhead

2. Real-time Output Streaming

Choice: BufReader with line-by-line streaming Rationale:

• User sees build progress immediately
• Can debug build failures in real-time
• Better UX for long builds
• Standard pattern for CLI tools

3. Builder Pattern for Options

Choice: DockerBuildOptions with builder methods Rationale:

• Flexible API for future extensions
• Self-documenting code
• Type-safe configuration
• Optional parameters with defaults

4. Progress Indicators

Choice: indicatif::ProgressBar with spinner Rationale:

• Visual feedback that process is running
• Professional CLI appearance
• Updates with current build step
• Clears on completion (no clutter)

5. Error Handling Strategy

Choice: Validate early, fail fast, provide context Rationale:

• Check Docker installation before attempting build
• Validate file paths before running commands
• Capture stderr for detailed error messages
• Suggest fixes in error messages

Configuration Integration

The build command integrates with the config system:

[docker]
registry = "jgrusewski"          # Docker Hub username or registry
image_name = "foxhunt"           # Image name
tag = "latest"                   # Default tag (overridden by --tag)

Tag Resolution:

Full Tag = {config.docker.registry}/{config.docker.image_name}:{args.tag}
Example:   jgrusewski/foxhunt:latest

Future Enhancements

While not implemented in Milestone 2, the design supports:

1. Build Args: The build_arg() method exists but isn't exposed via CLI yet
2. Multi-platform Builds: Could add --platform linux/amd64,linux/arm64
3. BuildKit Features: Could enable BuildKit-specific features
4. Parallel Builds: Could build multiple tags simultaneously
5. Registry Selection: Could support multiple registries
6. Image Inspection: Could show image size, layers, etc.

Files Changed

New Files (3)

• src/docker/mod.rs - Docker utilities (57 lines)
• src/docker/build.rs - Build implementation (194 lines)
• src/docker/push.rs - Push implementation (119 lines)
• tests/docker_integration_tests.rs - Integration tests (177 lines)

Modified Files (2)

• src/main.rs - Added docker module import
• src/cli/build.rs - Replaced stub with real implementation (38 lines)

Fixed Files (1)

• src/runpod/deployment.rs - Fixed ownership issue on line 43

Total: ~585 lines of production code + tests

Compilation Status

$ cargo build
   Compiling foxhunt-deploy v1.0.0
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 15.17s

$ cargo test --package foxhunt-deploy docker::
    Finished `test` profile [unoptimized] target(s) in 2.24s
     Running unittests src/main.rs

running 5 tests
test docker::build::tests::test_build_options_defaults ... ok
test docker::build::tests::test_build_options_builder ... ok
test docker::tests::test_verify_docker_available ... ok
test docker::push::tests::test_check_registry_auth ... ok
test docker::tests::test_image_exists ... ok

test result: ok. 5 passed; 0 failed; 0 ignored

Milestone Completion Checklist

• ✅ Create Docker module structure (mod.rs, build.rs, push.rs)
• ✅ Implement DockerBuildOptions with builder pattern
• ✅ Implement build_image() with real-time output streaming
• ✅ Implement push_image() with progress indication
• ✅ Add Docker daemon verification
• ✅ Update build subcommand to use Docker module
• ✅ Add unit tests (5 tests)
• ✅ Add integration tests (14 tests)
• ✅ Verify all tests pass
• ✅ Handle errors gracefully with actionable messages
• ✅ Use indicatif for progress bars
• ✅ Stream Docker output in real-time
• ✅ Support all CLI flags (--tag, --no-push, --no-cache, --dockerfile, --context)
• ✅ Validate Docker installation and image existence

Next Steps (Milestone 3)

The next milestone should implement RunPod deployment functionality:

1. Complete src/runpod/deployment.rs implementation
2. Integrate with src/cli/deploy.rs
3. Add RunPod API client functionality
4. Test end-to-end deployment workflow

Notes

• The implementation prioritizes reliability and error handling
• All error messages are actionable and suggest fixes
• The builder pattern makes it easy to extend functionality
• Real-time output streaming provides immediate feedback
• Tests validate both success and error paths