[Copilot]

Overview

This PR comprehensively updates all project documentation to reflect the cache-fallback feature and system_status table introduced in #4. The documentation now accurately describes the current system architecture, error handling behavior, and database schema.

Changes Made

1. README.md - User-Facing Documentation

• Added cache fallback to the features list, highlighting the system's resilience during upstream API outages
• Expanded database section to document all 8 tables (including the new system_status table)
• New cache fallback strategy section explaining which endpoints have fallback behavior and when 503 errors occur
• Enhanced troubleshooting with clear explanations of 404 vs 503 status codes
• Added documentation index with links to all major documentation files
• Fixed upstream API URL reference to https://api.helldivers2.dev

2. DEVELOPMENT.md - Developer Guide

• Updated database.py section to include all new snapshot methods (get_latest_*_snapshot()) and status tracking methods
• New cache fallback behavior section explaining the pattern with status code semantics
• Added implementation guide with code example for adding cache fallback to new endpoints
• System status tracking section documenting the system_status table purpose and usage
• Database migration notes for upgrading from pre-cache-fallback versions (automatic migration via CREATE TABLE IF NOT EXISTS)
• Troubleshooting section for 503 errors and cache debugging

3. docs/API.md - API Reference

• Documented cache fallback on all 5 affected endpoints:
  • GET /api/campaigns
  • GET /api/planets
  • GET /api/planets/{planet_index}
  • GET /api/factions
  • GET /api/biomes
• Added 503 error responses with specific examples for each endpoint
• Comprehensive error responses section explaining the semantic difference between 404, 500, and 503 status codes
• Added "Understanding Cache Fallback" section to help API consumers implement proper retry logic

4. docs/ARCHITECTURE.md - System Architecture

• Complete database schema documentation for all 8 tables with SQL DDL
• Detailed system_status table section including purpose, schema, and current status keys
• Updated data flow diagram showing cache fallback path and upstream status tracking
• New cache fallback flow diagram illustrating the decision tree (live API → cache → 503)
• Updated API lifecycle sections to show when set_upstream_status() is called

5. .github/copilot-instructions.md - AI Agent Instructions

• Updated component descriptions with accurate line counts and table counts
• Enhanced lifecycle & integration section with cache fallback behavior
• New pattern section "Adding Cache Fallback to Endpoints" with step-by-step guide
• Updated database conventions to include system_status usage pattern (INSERT OR REPLACE)

6. Documentation Cleanup

• Added .gitignore entries for development artifact files (*_SUMMARY.md, COMPLETE_GUIDE.md, etc.)
• Verified inline code comments in all source files for accuracy
• Ensured cross-references between documentation files are consistent

Cache Fallback Feature Summary

The cache-fallback feature provides graceful degradation when the upstream Hell Divers 2 API is unavailable:

Behavior:

1. Endpoint attempts to fetch live data from upstream API
2. If upstream fails, endpoint retrieves most recent cached data from database
3. If cache exists, returns 200 OK with cached data (transparent to client)
4. If no cache exists, returns 503 Service Unavailable

System Status Tracking:

• New system_status table tracks upstream_api_available boolean
• Updated after each collection cycle (success=true, failure=false)
• Enables monitoring and alerting on upstream API health

Database Changes:

• New table: system_status with indexed status_key column
• New methods: get_latest_*_snapshot() for cache retrieval
• New methods: set_upstream_status() and get_upstream_status()
• Migration: Automatic via CREATE TABLE IF NOT EXISTS (no manual steps required)

Testing

All changes are documentation-only. Verified:

• ✅ Python syntax remains valid (python -m py_compile src/*.py)
• ✅ All imports successful
• ✅ Documentation completeness (cache fallback: 4 mentions, 503 codes: 11 mentions, system_status: 8 mentions)
• ✅ Cross-references consistent across all files
• ✅ Git working tree clean with all changes committed

Related Issues

Closes #5

Documentation Stats

• Total documentation: 2,045+ lines across 6 primary files
• Lines added: 339
• Lines removed: 15 (outdated content)
• Files modified: 6 documentation files
• Cross-references: Verified consistent

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For API Consumers: The cache-fallback feature improves uptime during upstream outages. A 200 OK response may now contain cached data. Implement retry logic for 503 responses, as they indicate both upstream failure AND no cached data available.

For Developers: See DEVELOPMENT.md for the cache fallback implementation pattern and how to add it to new endpoints.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Clean up and update documentation/instructions</issue_title>
<issue_description>## Overview
Update and consolidate project documentation to reflect recent changes and improvements made in the cache-fallback feature implementation.

Tasks

• Review and update README.md with latest architecture changes
• Update DEVELOPMENT.md with new system_status table and upstream API status tracking
• Update API documentation (docs/API.md) to reflect 503 status codes for cache fallback endpoints
• Update architecture documentation (docs/ARCHITECTURE.md) with database schema changes
• Review .github/copilot-instructions.md and align with implemented changes
• Verify all inline code comments are accurate and helpful
• Remove or consolidate redundant documentation files
• Add migration notes for database schema (new system_status table)

Acceptance Criteria

• All documentation is current and accurate
• New features (cache fallback, upstream status tracking) are clearly documented
• API consumers understand 503 vs 404 error codes
• Database schema changes are documented with migration guidance
• All documentation files reference each other consistently</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes #5

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✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[surrealwolf]

looks good

[Copilot]

Pull Request Overview

This PR updates all project documentation to reflect the cache-fallback feature and system_status table introduced in PR #4. The documentation now accurately describes the system's ability to serve cached data during upstream API outages, the new 503 error semantics, and the enhanced database schema with the system_status table for tracking upstream API health.

Key Changes:

• Added comprehensive cache fallback documentation across all relevant files
• Documented the new system_status table and its purpose
• Clarified error code semantics (404 vs 503 vs 500) for API consumers
• Updated architecture diagrams to show cache fallback flow

Reviewed Changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
docs/ARCHITECTURE.md	Added cache fallback flow diagram, system_status table schema, and updated API lifecycle to include upstream status tracking
docs/API.md	Documented cache fallback behavior on 5 endpoints, added 503 error responses with examples, and explained status code semantics
README.md	Added cache fallback to features list, documented all 8 database tables, added cache fallback strategy section, and updated troubleshooting guide
DEVELOPMENT.md	Added cache fallback implementation guide, system_status table documentation, and database migration notes
.github/copilot-instructions.md	Updated component descriptions with accurate line counts and table counts, added cache fallback pattern guide