---
id: T01
parent: S03
milestone: M001
provides:
  - "parse_vpc_flow_log_line: VPC Flow Log v2 line parser (pure function)"
  - "compute_dedup_key: SHA-256 deduplication on 7-field composite key"
  - "ingest_local_files: async local file ingestion with glob expansion"
  - "IngestionResult: Pydantic model with records, stats, and warnings"
  - "ParseError, S3AccessError exception subclasses"
requires: []
affects: []
key_files: []
key_decisions: []
patterns_established: []
observability_surfaces: []
drill_down_paths: []
duration: 5min
verification_result: passed
completed_at: 2026-03-08
blocker_discovered: false
---
# T01: 03-log-ingestion 01

**# Phase 3 Plan 1: Log Ingestion Core Summary**

## What Happened

# Phase 3 Plan 1: Log Ingestion Core Summary

**VPC Flow Log v2 parser with async local file ingestion, SHA-256 deduplication, and IngestionResult tracking**

## Performance

- **Duration:** 5 min
- **Started:** 2026-03-09T05:32:58Z
- **Completed:** 2026-03-09T05:37:50Z
- **Tasks:** 2
- **Files modified:** 13

## Accomplishments
- VPC Flow Log v2 parser handling all field mappings (IANA protocols, action codes, sentinel values, timestamps)
- Async local file ingestion with glob expansion, missing-file resilience, and malformed-line warnings
- SHA-256 deduplication using 7-field composite key removes duplicates within an ingestion run
- IngestionResult Pydantic model tracks records, total_lines, duplicates_removed, errors_skipped, source_files, and warnings
- 43 ingestion-specific tests (120 total), pyright strict clean, ruff lint clean

## Task Commits

Each task was committed atomically:

1. **Task 1: VPC Flow Log parser, IngestionResult model, dedup, and test scaffolding**
   - `e39f426` (test: RED -- failing tests for parser, dedup, result)
   - `3bc1833` (feat: GREEN -- parser, dedup, result implementation)
2. **Task 2: Local file ingestion with async I/O, glob expansion, and deduplication**
   - `7791832` (test: RED -- failing tests for local ingestion)
   - `9b2736e` (feat: GREEN -- local ingestion implementation)

_TDD tasks each have RED + GREEN commits._

## Files Created/Modified
- `src/policyfoundry/ingestion/parser.py` - VPC Flow Log v2 line parser (pure function, never raises)
- `src/policyfoundry/ingestion/result.py` - IngestionResult Pydantic model with records and stats
- `src/policyfoundry/ingestion/dedup.py` - SHA-256 dedup key computation on 7-field composite
- `src/policyfoundry/ingestion/local.py` - Async local file ingestion with glob expansion
- `src/policyfoundry/ingestion/__init__.py` - Public API exports
- `src/policyfoundry/exceptions.py` - Added ParseError, S3AccessError subclasses
- `pyproject.toml` - Added aiofiles, pytest-asyncio, asyncio_mode=auto
- `tests/test_ingestion/conftest.py` - Shared fixtures (valid/header/nodata/skipdata/malformed lines)
- `tests/test_ingestion/test_parser.py` - 20 parser tests covering all field mappings and edge cases
- `tests/test_ingestion/test_dedup.py` - 10 dedup tests for consistency and collision resistance
- `tests/test_ingestion/test_local.py` - 13 integration tests for local ingestion

## Decisions Made
- parse_vpc_flow_log_line is a pure function that never raises -- returns None on any failure
- NODATA/SKIPDATA lines are silently skipped (not counted as errors) since they are AWS metadata
- Dedup key uses 7 fields (src_ip, dst_ip, src_port, dst_port, protocol, timestamp, action) -- excludes bytes_transferred and packets_count
- flow_direction defaults to INBOUND for all v2 lines (v2 format lacks direction info)
- Non-version-2 lines log warning but still attempt parse (graceful degradation)

## Deviations from Plan

None - plan executed exactly as written.

## Issues Encountered
None

## User Setup Required
None - no external service configuration required.

## Next Phase Readiness
- Local file ingestion pipeline complete and tested end-to-end
- Parser, dedup, and IngestionResult ready for S3 ingestion (Plan 02) to reuse
- All public APIs exported from ingestion __init__.py for downstream consumers

## Self-Check: PASSED

All 12 files verified present. All 4 commits verified in git history.

---
*Phase: 03-log-ingestion*
*Completed: 2026-03-08*
