feat: Implement robust Couchbase error handling and modernize test infrastructure

[teetangh]

Summary

This PR implements comprehensive improvements to Couchbase integration, error handling, test infrastructure, and API documentation. The changes ensure the application handles database failures gracefully, provides clear operational visibility, and maintains a clean separation between testing and documentation.

Key Changes

1. Graceful Degradation & Error Handling ✅

New CouchbaseConnection Concern (app/models/concerns/couchbase_connection.rb)

• Centralized Couchbase availability checking across all models
• ensure_couchbase! method validates connection before operations
• Raises descriptive CouchbaseUnavailableError instead of cryptic NoMethodError
• Applied to: Airline, Airport, Route, Hotel models

Enhanced ApplicationController

• Global error handler for CouchbaseUnavailableError
• Returns HTTP 503 (Service Unavailable) with clear error messages
• Enables app to start without database, fail gracefully per-request

Improved Couchbase Initializer (config/initializers/couchbase.rb)

• Retry logic for transient network failures (3 attempts, 2s delay)
• Environment-specific error handling:
  • Production: Abort startup if database unavailable
  • Development: Warn but allow app to start
  • Test: Warn with clear setup instructions
• Fixed constant re-assignment warnings (local vars in dev)
• Added helper methods for cleaner initialization

2. Health Check Endpoint 🏥

New Endpoint: GET /api/v1/health

• Returns service health status with Couchbase connectivity
• HTTP 200 if all services up, 503 if any down
• Includes timestamp and detailed service statuses
• Example response:

{
  "status": "healthy",
  "timestamp": "2025-12-02T10:00:00Z",
  "services": {
    "couchbase": {
      "status": "up",
      "message": "Connected to travel-sample bucket"
    }
  }
}

3. Test Infrastructure Modernization 📁

Reorganized Test Structure:

• Moved integration tests: test/integration/ → spec/requests/api/v1/
• Created swagger docs: spec/requests/swagger/
• Clear separation: integration tests validate functionality, swagger specs generate docs
• Deleted obsolete test/integration/ directory

Swagger Specs Simplified:

• Converted to documentation-only (no database setup/teardown)
• 64/64 specs pass cleanly for swagger generation
• Added inline comments referencing actual integration tests
• Faster execution, no test data management complexity

Integration Tests:

• 27/27 tests passing against travel-sample database
• Comprehensive coverage of Airlines, Airports, Routes APIs
• Proper cleanup with ensure blocks
• Tests for success, conflict, and error cases

4. Model Consistency 🏗️

Renamed HotelSearch → Hotel

• Consistent naming with other models (Airline, Airport, Route)
• Updated controller, routes, and all references
• Maintains same functionality, cleaner architecture

5. CI/CD Improvements 🔄

Updated GitHub Actions Workflow (.github/workflows/ci.yml)

• Added Couchbase configuration validation step
• Connection test before running specs
• Separated concerns:
  • Run integration tests: rspec spec/requests/api/v1
  • Verify swagger generates: rake rswag:specs:swaggerize
• Added manual workflow dispatch trigger
• Environment-specific handling

6. Documentation 📚

Enhanced README.md:

• Comprehensive troubleshooting section
• Environment variable verification commands
• Connection testing instructions
• Bucket/scope/collection verification
• Permission requirements for Couchbase Capella
• Network access setup guide
• CI configuration instructions
• Common error solutions
• Health check endpoint documentation

Regenerated Swagger Documentation:

• Clean generation from simplified specs
• All grammar and description improvements included
• Updated hotel API endpoints

Testing Results

✅ All Tests Passing

Integration Tests: 27/27 passing

Airlines API:    10/10 ✅
Airports API:    11/11 ✅
Routes API:       6/6  ✅

Swagger Generation: 64/64 passing

Finished in 0.014s
64 examples, 0 failures

Test Coverage

• ✅ GET, POST, PUT, DELETE operations for all resources
• ✅ List/search operations with pagination
• ✅ Error cases (404, 409, 400, 503)
• ✅ Database unavailable scenarios
• ✅ Input validation

Benefits

Operational

• Better observability: Health check endpoint for monitoring
• Graceful degradation: App starts without database, clear error messages
• Faster debugging: Descriptive errors instead of "undefined method 'get' for nil"

Development

• Faster tests: Documentation-only swagger specs
• Clear separation: Testing vs documentation concerns
• Better DX: Comprehensive troubleshooting guide

Maintenance

• Consistent patterns: Shared CouchbaseConnection concern
• Retry logic: Handles transient network failures
• CI reliability: Validation steps catch config issues early

Migration Notes

No breaking changes to API contracts. All endpoints maintain same behavior.

For Developers

• New GET /api/v1/health endpoint available for monitoring
• Integration tests now in spec/requests/api/v1/
• Run specs: bundle exec rspec spec/requests/api/v1
• Generate swagger: bundle exec rake rswag:specs:swaggerize

For CI/CD

• Ensure environment variables set: DB_CONN_STR, DB_USERNAME, DB_PASSWORD
• Validation steps will fail fast if config missing
• Health check can be used for readiness probes

Related

• Addresses Gemini Code Assist feedback
• Fixes integration test failures from previous work
• Improves operational readiness for production deployment

---

🤖 Generated with Claude Code

Co-Authored-By: Claude [email protected]

[gemini-code-assist]

Summary of Changes

Hello @teetangh, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request primarily focuses on enhancing the robustness of Couchbase initialization and expanding the API documentation within Swagger. It introduces error handling for Couchbase connection issues and adds new endpoints for hotel search functionalities, while also simplifying the Swagger server URL configuration.

Highlights

• Improved Couchbase Initialization: The Couchbase connection logic is now wrapped in a begin...rescue block, allowing the Rails application to boot even if Couchbase is unreachable or misconfigured. Uninitialized constants will be set to nil in such cases.
• New Hotel API Endpoints in Swagger: Two new API endpoints, /api/v1/hotels/autocomplete (GET) and /api/v1/hotels/filter (POST), have been added to the Swagger documentation, enabling hotel search and filtering capabilities.
• Simplified Swagger Server URL: The Swagger server URL configuration has been streamlined from a dynamic http://{defaultHost} to a more generic and relative /.

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