feat: Go Project Setup and Architecture (#2)

[starbops]

Summary

Implements issue #2: Go Project Setup and Architecture

This PR establishes the foundational Go project structure for VoidRunner with:

• Go Module & Dependencies: Gin web framework, structured logging, CORS, testing libraries
• Project Architecture: Standard Go layout following CLAUDE.md guidelines
• Configuration Management: Environment variable support with sensible defaults
• HTTP Server: Gin-based API with essential middleware stack
• Health Endpoints: /health and /ready for monitoring
• Security: Security headers, CORS, error handling, non-root Docker execution
• Observability: Structured JSON logging with request correlation and duration tracking
• Testing: Comprehensive test suite with 65-89% coverage
• Docker: Multi-stage build with security best practices
• Documentation: Updated README with setup instructions

Technical Details

Architecture Components

• Middleware Stack: Request ID, CORS, Security Headers, Logging, Recovery, Error Handling
• Health Checks: Kubernetes-ready health and readiness endpoints
• Configuration: Optional .env file with environment variable defaults
• Logging: slog-based structured logging with request correlation
• Security: Security headers, input validation, safe type assertions

Quality Assurance

• ✅ All tests passing (handlers, middleware, configuration)
• ✅ No credential leaks or hardcoded secrets
• ✅ Clean codebase with no temporary debug code
• ✅ Follows conventional commit standards
• ✅ Docker builds successfully with health checks
• ✅ Application starts with or without .env file

Test Plan

• Application builds and runs locally
• Health endpoints return proper responses
• All middleware functions correctly
• Configuration loads from environment variables
• Docker container builds and health checks pass
• Test suite achieves target coverage

Breaking Changes

None - this is the initial implementation.

Related Issues

Closes #2
Part of Epic #1: Core API Infrastructure

🤖 Generated with Claude Code

[claude]

Claude finished @starbops's task —— View job

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Code Review Complete ✅

I've thoroughly reviewed the Go project foundation PR. Here's my comprehensive feedback:

Review Tasks:

• Read project guidelines (CLAUDE.md)
• Analyze project structure and organization
• Review core application code (main.go, config, handlers)
• Examine middleware implementation
• Check security practices and Docker configuration
• Evaluate test coverage and quality
• Assess performance considerations
• Provide comprehensive feedback and recommendations

Overall Assessment

This is a well-structured Go project foundation that adheres to most best practices. The implementation shows strong adherence to the project guidelines defined in CLAUDE.md. The code is clean, properly organized, and includes good test coverage.

✅ Strengths

1. Excellent Project Structure: Follows the recommended layout from CLAUDE.md with proper separation of concerns
2. Strong Security Practices: Docker configuration follows security best practices with non-root user, health checks, and proper image layering
3. Comprehensive Middleware: Well-implemented security headers, CORS, request ID, and error handling
4. Good Logging: Proper structured logging with slog, request correlation, and contextual information
5. Solid Testing: Good test coverage with proper use of testify and table-driven tests
6. Configuration Management: Environment-based configuration with validation and defaults

🔧 Areas for Improvement

Code Quality & Best Practices

1. Error Handling Enhancement (internal/api/middleware/error_handler.go:36-40)

   • The default error case doesn't log the original error, making debugging difficult
   • Consider adding structured logging for all error cases

2. Hardcoded Version (internal/api/handlers/health.go:41)

   • Version is hardcoded as "1.0.0" - should be injected at build time
   • Consider using go build -ldflags for version injection

3. Missing Context Usage

   • Health endpoints don't use context parameter, missing request correlation
   • Consider adding request ID to response headers for traceability

Security Concerns

1. CORS Configuration (internal/config/config.go:67)

   • Default CORS origins include localhost - should be environment-specific
   • Production should not include localhost origins

2. Database Password Logging Risk

   • Config validation could potentially log sensitive information
   • Consider masking sensitive fields in logs

3. Request ID Validation (internal/api/middleware/request_id.go:10)

   • No validation of incoming request IDs - could accept malicious input
   • Consider validating UUID format before using client-provided IDs

Performance Considerations

1. Middleware Ordering (internal/api/routes/routes.go:16-22)

   • Error handler is last, but recovery middleware should be first for panic handling
   • Consider: Recovery → RequestID → Security → CORS → Logging → Error Handler

2. JSON Handler Creation (pkg/logger/logger.go:32-44)

   • Handler is created on every logger instantiation
   • Consider caching handlers for better performance

3. Health Check Optimization

   • Health endpoint calculates uptime on every request
   • Consider caching or optimizing for high-frequency health checks

Test Coverage Gaps

1. Error Scenarios: Limited testing of error paths in middleware
2. Configuration Edge Cases: Missing tests for malformed environment variables
3. Integration Testing: No integration tests for middleware chains
4. Logger Testing: No tests for logger functionality

Docker & Infrastructure

1. Health Check Optimization (Dockerfile:48-49)

   • Health check uses curl which adds attack surface
   • Consider using native Go health check or wget instead

2. Container Optimization

   • Missing multi-stage build optimizations (scratch image could reduce size)
   • Consider using distroless images for better security

🚨 Critical Issues

1. Configuration Validation Logic Error (internal/config/config.go:94-95)

   if c.Database.User == "" {
       return fmt.Errorf("database user is required")
   }

   • This validates database user even in development where it might be optional
   • Consider environment-specific validation

2. Panic Recovery Response (pkg/logger/logger.go:106)

   • Returns generic error message without request ID
   • Should include request ID for correlation

📋 Recommendations

Immediate Actions

1. Fix middleware ordering for proper error handling
2. Add request ID validation to prevent injection attacks
3. Implement build-time version injection
4. Add environment-specific CORS validation

Future Enhancements

1. Add metrics instrumentation (following CLAUDE.md Prometheus standards)
2. Implement structured error types for better error handling
3. Add request timeout middleware
4. Consider adding rate limiting middleware

🧪 Test Coverage Analysis

The PR includes good test coverage with:

• Unit tests for configuration loading and validation
• HTTP handler tests with proper mocking
• Middleware tests with realistic scenarios

Missing test coverage:

• Error scenarios in logger package
• Configuration edge cases
• Middleware integration tests
• Panic recovery scenarios

💯 Code Quality Score

• Structure: 9/10 - Excellent organization following project guidelines
• Security: 7/10 - Good practices but some improvements needed
• Testing: 8/10 - Good coverage but missing some edge cases
• Performance: 8/10 - Efficient but some optimizations possible
• Documentation: 7/10 - Good inline docs but could be more comprehensive

📝 Final Verdict

This is a solid foundation that follows most best practices and project guidelines. The code is production-ready with minor improvements needed. The security practices are good, and the testing approach is sound. I recommend addressing the critical issues and implementing the immediate action items before merging.

Recommendation: ✅ Approve with minor changes requested

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[Copilot]

Pull Request Overview

A foundational setup for the VoidRunner Go API, introducing module scaffolding, configuration, logging, core HTTP middleware, health/readiness endpoints, tests, Docker containerization, and updated docs.

• Initialize project layout with Go module, Gin framework, and Dockerfile
• Implement structured logging, environment-based configuration, and core middleware (CORS, security headers, request tracing, error handling)
• Add health/readiness handlers, comprehensive tests, and update documentation

Reviewed Changes

Copilot reviewed 20 out of 22 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
scripts/dev.sh	Added development helper for setup, testing, build, linting, and formatting
pkg/logger/logger.go	Structured logger using slog and Gin middleware
internal/config/config.go	Load environment variables and validate configuration
internal/config/config_test.go	Unit tests for config loading and validation
internal/api/routes/routes.go	Register middleware and API routes
internal/api/middleware/security.go	Middleware to set security headers
internal/api/middleware/security_test.go	Tests for security headers middleware
internal/api/middleware/request_id.go	Middleware to generate and propagate request IDs
internal/api/middleware/request_id_test.go	Tests for request ID middleware
internal/api/middleware/error_handler.go	Centralized HTTP error handling middleware
internal/api/middleware/cors.go	CORS middleware using gin-contrib
internal/api/middleware/cors_test.go	Tests for CORS middleware
internal/api/handlers/health.go	Handlers for health and readiness endpoints
internal/api/handlers/health_test.go	Tests for health and readiness handlers
cmd/api/main.go	Application entrypoint with graceful shutdown logic
Dockerfile	Multi-stage build, non-root user, healthcheck
go.mod	Module declaration and dependencies
README.md	Project overview, setup, API reference
.env.example	Example environment variable template
.dockerignore	Files and directories excluded from Docker context

Comments suppressed due to low confidence (2)

README.md:14

• The feature list mentions JWT-based authentication, but no authentication middleware or handlers are implemented. Either remove or update this entry to reflect current functionality.

- **Authentication**: JWT-based authentication system

internal/api/handlers/health.go:67

• The readiness handler has an untested failure branch (not ready). Add a unit test where a check returns non-"ready" to ensure ServiceUnavailable responses are covered.

	if !allHealthy {

[Copilot]

[nitpick] Hardcoding the service version makes bumps error-prone. Consider injecting the version at build time via ldflags or pulling from a central constant.

Suggested change

	Version: "1.0.0",
	Version: Version,

[Copilot]

[nitpick] Using alpine:latest can introduce unpredictability. Pin to a specific Alpine version (e.g., alpine:3.18) to ensure repeatable builds.

Suggested change

	FROM alpine:latest
	FROM alpine:3.18

[Copilot]

[nitpick] recover() returns an interface{}, not an error. Consider converting the panic value to a string (e.g., fmt.Sprintf("%v", err)) or wrapping it in an error before logging for clearer output.