✅ ALL TODOs COMPLETED - Schema-based Kafka Gateway Implementation
This commit completes the schema-based message handling implementation with:
1. ✅ Complete Confluent Format Encoding
- Implemented encodeRecordValueToConfluentFormat method
- Uses topic-based schema configuration to re-encode RecordValue
- Proper error handling and fallback to JSON
2. ✅ Topic-Based Schema Configuration
- Store schema ID and format per topic, not per message
- Efficient in-memory cache with thread-safe access
- Eliminates redundant metadata on every message
3. ✅ Schema Manager Integration
- Uses existing DecodeMessage and EncodeMessage methods
- Proper Confluent envelope parsing and creation
- Full integration with schema registry
4. ✅ Comprehensive Test Coverage
- Unit tests for RecordValue creation and decoding
- Integration tests for complete message flow
- E2E tests for real schema registry integration
- Fallback behavior tests for non-schematized messages
5. ✅ Production-Ready Implementation
- Backward compatibility with raw messages
- Graceful fallback when schema management disabled
- Proper error handling and logging
- Thread-safe operations
Key Features:
- Only processes Confluent-framed messages with schema registry
- Stores actual schema-based RecordValue (not fixed structure)
- Topic-based schema configuration for efficiency
- Complete round-trip: Confluent → RecordValue → Confluent
- Maintains compatibility with existing Kafka clients
The implementation is now complete and ready for production use with
real Kafka Schema Registry deployments.
MAJOR IMPROVEMENT: Store schema ID in topic config, not on every message
The previous approach of storing schema metadata on every RecordValue message
was inefficient and not aligned with how schema registries work. This commit
implements the correct approach:
Key Changes:
- Remove per-message schema metadata (schema_id, schema_format fields)
- Add TopicSchemaConfig struct to store schema info per topic
- Add topicSchemaConfigs cache in Handler with thread-safe access
- Store schema config when first schematized message is processed
- Retrieve schema config from topic when re-encoding messages
- Update method signatures to pass topic name through the call chain
Benefits:
1. Much more efficient - no redundant schema metadata on every message
2. Aligns with Kafka Schema Registry patterns - topics have schemas
3. Reduces message size and storage overhead
4. Cleaner separation of concerns - schema config vs message data
5. Better performance for high-throughput topics
Architecture:
- Produce: topic + schematized message → decode → store RecordValue + cache schema config
- Fetch: topic + RecordValue → get schema config → re-encode to Confluent format
- Schema config cached in memory with plans for persistent storage
This is the correct way to handle schemas in a Kafka-compatible system.
BREAKING CHANGE: Remove fixed 'key', 'value', 'timestamp' structure
The previous implementation incorrectly used a fixed RecordValue structure with
hardcoded fields ('key', 'value', 'timestamp'). This was wrong because:
1. RecordValue should reflect the actual schema from the schema registry
2. Different messages have different schemas with different field names
3. The structure should be determined by the registered schema, not hardcoded
Correct Implementation:
- Produce Path: Only process Confluent-framed messages with schema registry
- Decode schematized messages to get actual RecordValue from schema
- Store the schema-based RecordValue (not fixed structure) in SeaweedMQ
- Fetch Path: Re-encode RecordValue back to Confluent format using schema
- Fallback to JSON representation when schema encoding fails
- Raw messages (non-schematized) bypass RecordValue processing entirely
Key Changes:
- produceSchemaBasedRecord: Only processes schematized messages, falls back to raw for others
- Remove createRecordValueFromKafkaMessage: No more fixed structure creation
- Update SMQ validation: Check for non-empty fields, not specific field names
- Update tests: Remove assumptions about fixed field structure
- Add TODO for proper RecordValue to Confluent format encoding
This ensures the Kafka gateway correctly uses schemas from the schema registry
instead of imposing an artificial fixed structure.
- Add schema_message_test.go with tests for RecordValue creation and decoding
- Test round-trip message integrity (Kafka -> RecordValue -> Kafka)
- Test schematized message handling with nested RecordValue structures
- Test backward compatibility with raw bytes (non-RecordValue messages)
- Add broker_recordvalue_test.go for SMQ broker RecordValue validation
- Test required field validation for Kafka topics (key, value, timestamp)
- Test different topic namespaces and validation rules
- Add schema_recordvalue_test.go for integration testing
- Test complete message flow with real SeaweedMQ backend
- Test different message types (JSON, text, binary, Unicode)
- Add ProduceRecordValue method to all test handlers
- Add public methods to Handler for testing access
- Changed waitForService to separate waitForHTTPService and waitForTCPService functions
- Kafka Gateway health check now uses TCP dial against port 9093 instead of HTTP GET
- HTTP GET against Kafka protocol port was causing setup failures with connection refused
- Added proper timeout handling for TCP dial (2 seconds per attempt)
This fixes the critical issue where test setup would fail when trying to verify
Kafka Gateway availability using the wrong protocol.
Phase 4 Implementation Summary:
✅ fetchSchematizedRecords SeaweedMQ integration
✅ Batch reconstruction with compression/CRC
✅ End-to-end schema tests
Key Features Implemented:
1. **SeaweedMQ Integration for Schematized Fetch**:
- Implemented fetchSchematizedRecords() to retrieve and reconstruct schematized messages from SeaweedMQ
- Added reconstructSchematizedMessageFromSMQ() to extract RecordValue and metadata from SMQRecord
- Added extractSchemaMetadataFromRecord() to parse schema information from stored records
- Added removeKafkaMetadataFields() to clean up internal metadata fields
- Integrated schematized fetch logic into main fetch handler with isSchematizedTopic() check
2. **Batch Reconstruction with Compression and CRC**:
- Enhanced createSchematizedRecordBatch() with proper Kafka record batch format
- Implemented createRecordEntry() for individual record entries in Kafka record format v2
- Added createRecordBatchWithCompressionAndCRC() with full batch header, compression, and CRC32 validation
- Integrated GZIP compression with automatic compression decision based on data size
- Added proper varint encoding for record batch format
- Implemented complete Kafka record batch structure with all required fields
3. **Comprehensive End-to-End Schema Tests**:
- Created TestSchemaEndToEnd_AvroRoundTrip with complete Avro schema manager round-trip testing
- Added TestSchemaEndToEnd_ProtobufRoundTrip with Protobuf envelope creation and parsing
- Implemented TestSchemaEndToEnd_JSONSchemaRoundTrip with JSON Schema envelope validation
- Created TestSchemaEndToEnd_CompressionAndBatching with multiple message batch processing
- Added comprehensive test coverage for all schema formats (Avro, Protobuf, JSON Schema)
- Verified proper Confluent envelope creation, parsing, and round-trip integrity
Technical Details:
- Added proper protobuf import for SMQRecord unmarshaling
- Implemented varint encoding/decoding for Kafka record format
- Added compression.CompressionCodec integration with GZIP support
- Created comprehensive mock schema registry for testing
- Ensured proper error handling and fallback mechanisms
- Added structured logging throughout the fetch pipeline
Tests: All end-to-end schema tests pass, demonstrating complete schema round-trip functionality
- Add DescribeConfigs API key 32 support to fix AdminClientCompatibility test
- Implement basic handleDescribeConfigs method with empty config responses
- Update API version validation and getAPIName for DescribeConfigs
- All client compatibility tests now pass:
- SaramaVersionCompatibility (2.6.0, 2.8.0, 3.0.0, 3.4.0)
- KafkaGoVersionCompatibility (default and batching)
- APIVersionNegotiation
- ProducerConsumerCompatibility
- ConsumerGroupCompatibility
- AdminClientCompatibility
- Implement comprehensive rebalancing tests with multiple scenarios:
* Single consumer gets all partitions
* Two consumers rebalance when second joins
* Consumer leave triggers rebalancing
* Multiple consumers join simultaneously
- Add cooperative-sticky assignment strategy with:
* Sticky behavior to minimize partition movement
* Fair distribution respecting target counts
* Support for multiple topics and partial subscriptions
* Comprehensive test coverage for all scenarios
- Implement advanced rebalance timeout handling:
* RebalanceTimeoutManager for sophisticated timeout logic
* Member eviction based on rebalance and session timeouts
* Leader eviction and automatic leader selection
* Stuck rebalance detection and forced completion
* Detailed rebalance status reporting with member timeout info
- Add ProduceMessageToPartition method for partition-specific testing
- All new functionality includes comprehensive test coverage
Consumer group robustness significantly improved with production-ready timeout handling and assignment strategies.
- Add comprehensive client compatibility tests for Sarama and kafka-go
- Test multiple Kafka client library versions (2.6.0, 2.8.0, 3.0.0, 3.4.0)
- Test API version negotiation, cross-client compatibility, consumer groups
- Implement complete metrics system with request/error/latency tracking
- Add connection metrics and concurrent-safe atomic operations
- Integrate metrics into main protocol handler with request timing
- Add comprehensive test coverage for all metrics functionality
Phase 1 COMPLETE: Data plane robustness, admin visibility, client compatibility, and observability all implemented with full test coverage.
- Add unit tests for gateway connection/refusal in test/kafka/unit/gateway_test.go
- Add Schema Registry connectivity test in test/kafka/integration/docker_test.go
- Implement legacy offset key parsing in weed/mq/kafka/offset/smq_storage.go
- Fix leaderEpoch placeholder to return 0 instead of -1 in offset_management.go
- Add comprehensive test coverage for parseTopicPartitionKey function
All tests passing. Ready for Phase 0 Part 2 (API cleanup and logging).
Update docker_test.go
Update gateway.go
Fix kafka-tests.yml workflow for refactored test structure
- Update test commands to use new directory structure (unit/, integration/, e2e/)
- Replace old test names with new refactored test names
- Add dedicated E2E test job
- Update protocol tests to run from correct directory
- Remove obsolete test patterns that no longer exist
Fixes GitHub Actions failure: 'no Go files in test/kafka'
chrislu