Firestore Storage

[prosdev]

Phase: 2 - Storage Layer
Estimated Effort: 3-4 hours
Tasks: Task 4 from specs/core-pipeline/tasks.md

Checklist

Task 4: Implement Firestore Storage (3-4 hours)

• Create FirestoreEventStore (implements EventStore Protocol)
• Implement write() with batch operations (max 500 docs)
• Implement read() by stream
• Implement query() with filters
• Add retry logic for transient errors
• Create FirestoreErrorStore (implements ErrorStore Protocol)
• Implement write_error()
• Implement query_errors()
• Write unit tests (mocked Firestore client)
• Write integration tests (Firestore emulator)

Acceptance Criteria

• FirestoreEventStore implements EventStore Protocol
• Batch writes work (tested with 100+ events)
• Document ID format: {stream}/{timestamp}_{uuid}
• Retry logic handles transient errors
• FirestoreErrorStore captures invalid events
• Unit tests pass
• Integration tests with emulator pass

Files to Create

src/eventkit/stores/firestore.py
tests/unit/stores/test_firestore.py
tests/integration/test_firestore_integration.py

Dependencies: Issue #1
User Stories: Story 2 (Stream Isolation), Story 5 (Batch Processing), Story 6 (Dead Letter Queue)