Plan: Implement AMQP 0.9.1 Server in Go

Goal

Create a Go package github.com/maxpert/amqp-go that implements an AMQP 0.9.1 server based on the specification: https://www.rabbitmq.com/resources/specs/amqp0-9-1.extended.xml

Current Status (Updated: 2026-02-22)

Phase 14 - Log Compaction + Bug Fixes: COMPLETE ✅

Phase 14 - Post-Review Bug Fixes (Code Review Pass):

✅ Fix: readMessageFromFile body deserialization — Sequential scan path (WAL fallback when offset not in index) incorrectly returned body bytes including the 4-byte bodyLen prefix. Fixed by reading bodyLen field before slicing body, matching serializeMessage format. Test: TestWAL_SequentialScan_CorrectBody
✅ Fix: openNextSegment deadlock — writeMessage held qs.mutex while calling openNextSegment, which also tried to acquire qs.mutex — a non-reentrant deadlock. Split into openNextSegment() (acquires mutex) and openNextSegmentLocked() (precondition: caller holds mutex). writeMessage now calls openNextSegmentLocked(). Test: TestSegment_RolloverDuringWrite
✅ Fix: writeIndexToDisk ignores write errors — All binary.Write calls now check error return values and propagate failures, preventing silent index corruption on disk-full or I/O errors
✅ Fix: checkpointLoop interval race — Goroutine started before SetSegmentManager() was called, causing it to read segmentMgr == nil and always use the 5-minute default. Added CheckpointInterval to WALConfig (mapped from EngineConfig.SegmentCheckpointIntervalMS); checkpointLoop now uses qw.cfg.CheckpointInterval directly, removing the dependency on segmentMgr at goroutine start
58 tests pass, 0 data races (verified with -race)

Phase 14 - Log Compaction (Storage Reliability):

✅ Commit 1: Fix roaring64 bitmap and WAL offset tracking bug
- Replaced roaring.Bitmap → roaring64.Bitmap in WAL and segment managers (removes uint32 truncation at ~4.29B messages)
- Fixed tryDeleteOldFiles() offset iteration bug: now tracks actual message offsets per file via roaring64.Bitmap instead of iterating [minOffset, maxOffset] range
- Removed dead ackedMsgs/minOffset/maxOffset fields from walFileInfo, replaced with offsets *roaring64.Bitmap
- Added currentFileOffsets tracking in QueueWAL to capture offsets during flushBatch() and pass to rollFile()
- Updated readMessageSequential() to use bitmap Contains() instead of range check
- 5 new tests in wal_compaction_test.go: large offsets, sparse offsets, partial ACK, false positive regression, large offset recovery
✅ Commit 2: Wire EngineConfig to storage layer constructors
- Added WALConfig struct with DefaultWALConfig() and NewWALManagerWithConfig() constructor
- Added SegmentConfig struct with DefaultSegmentConfig() and NewSegmentManagerWithConfig() constructor
- Added WALConfigFromEngine() and SegmentConfigFromEngine() to map EngineConfig → storage configs
- Added NewDisruptorStorageWithEngineConfig() that passes config through to WAL/Segment constructors
- Updated server/builder.go to call NewDisruptorStorageWithEngineConfig() with EngineConfig
- All hardcoded constants (batch size, timeout, file size, channel buffer, cleanup/compaction/checkpoint intervals) now respect config
- 5 new tests: custom batch size, custom compaction threshold, engine→WAL mapping, engine→segment mapping, default fallback
✅ Commit 3: Fix segment deletedCount tracking
- Added acknowledgeInSegment() method that finds the segment containing an offset and increments its deletedCount
- Called from Acknowledge() after updating the ACK bitmap
- Checks both current segment (via currentIndex) and sealed segments (via segment.index)
- Fixed sealSegment() to copy currentIndex entries to segment.index for sealed-segment reads
- Fixed sealSegment() to reopen file as read-only for sealed-segment ReadAt support
- Fixed pre-existing CRC verification bug in readSegmentMessageAt() — was verifying CRC over wrong data slice
- 4 new tests: deletedCount increment, compaction triggers, compaction preserves unacked, regression test
✅ Commit 4: Implement WAL → Segment checkpointing
- Implemented performCheckpoint(): scans old WAL files, filters out ACKed messages, writes unACKed to segments, deletes WAL file, cleans offset index
- Added CheckpointBatch() on SegmentManager for bulk message writes during checkpoint
- Only operates on old/rolled files — never touches the active WAL file
- Updated checkpointLoop to use configurable interval from SegmentConfig
- 5 new tests: moves to segments, deletes old files, skips ACKed, active file untouched, offset index cleanup
✅ Commit 5: Add time-based WAL retention
- Added createdAt time.Time field to walFileInfo for tracking file age
- Added retention check in tryDeleteOldFiles(): files older than RetentionPeriod are force-deleted
- Added forceCheckpointFile() method: best-effort checkpoint of unACKed messages to segments before deletion
- Fixed segment openNextSegment() to use O_RDWR instead of O_WRONLY so checkpointed messages are readable from current segment
- Retention disabled by default (RetentionPeriod: 0); enabled via config
- 4 new tests: expired file deletion, recent file preservation, checkpoint-before-delete, disabled-when-zero
✅ Commit 6: Integration test and plan update
- Full lifecycle integration test (log_compaction_integration_test.go): write → WAL roll → checkpoint → segment → compaction → recovery
- TestLogCompaction_FullLifecycle: 300 durable messages across 3 queues, ACK 80%, checkpoint, verify unACKed readable, segment compaction, simulate restart
- TestLogCompaction_RetentionWithCheckpoint: time-based retention force-checkpoints unACKed messages to segments before deletion
- TestLogCompaction_LargeOffsetLifecycle: uint64 offsets > uint32 max through full WAL → segment pipeline
- TestLogCompaction_TierFallback: validates Ring Buffer → WAL → Segment three-tier read fallback

Phase 13 - Memory Allocation Optimizations: COMPLETE ✅

Phase 13 - Memory Allocation Optimizations:

✅ Buffer Pool Integration: Eliminated allocations in frame serialization hot path
- Implemented MarshalBinaryPooled() using tiered buffer pools from Phase 12
- Updated sendBasicDeliver to use pooled buffers for method/header/body frames
- Automatic buffer lifecycle management with defer statements
- Zero-allocation frame encoding for repeated operations
✅ ReadFrame Optimization: Switched to pooled header buffers across hot paths
- Replaced ReadFrame with ReadFrameOptimized in server connection handling
- Connection handshake (lines 194, 228, 240): 3 hot path optimizations
- Main frame reading loop (line 298): Continuous optimization in reader goroutine
- Reduces header buffer allocations by reusing pooled 7-byte buffers
✅ Timer Reuse: Eliminated repeated timer allocations in consumer delivery loop
- Single timer created outside loop with time.NewTimer()
- Proper Reset() pattern with channel draining before reuse
- Eliminated 450MB of timer allocations in hot loop
- Maintains 500μs select timeout without allocation overhead
✅ Allocation Reduction Achieved: 26.5% total allocation savings
- Before: 52.77 GB total allocations, 25.28GB in sendBasicDeliver
- After: 38.79 GB total allocations, 16.68GB in sendBasicDeliver
- Savings: 13.98 GB eliminated (26.5% reduction overall)
- sendBasicDeliver: 8.6 GB saved (34% reduction from 25.28GB → 16.68GB)
✅ Performance Maintained: Zero throughput regression
- Throughput: 130-140k msg/s sustained (same as pre-optimization)
- Peak memory: 459 MB (3% improvement from 473MB)
- All tests passing: Integration + Protocol test suites

Technical Implementation:

MarshalBinaryPooled (protocol/frame_optimized.go:118-157):
```
func (f *Frame) MarshalBinaryPooled() ([]byte, error)
// Usage: data, err := frame.MarshalBinaryPooled()
//        defer PutBufferForSize(&data)
```
- Uses GetBufferForSize() to select appropriate pool (1KB/64KB/131KB)
- Caller responsible for returning buffer with PutBufferForSize()
- Automatic fallback for oversized frames (rejected by pool on return)

Hot Path Updates (server/basic_handlers.go:705-763):

methodFrameData, _ := frame.MarshalBinaryPooled()
defer protocol.PutBufferForSize(&methodFrameData)

headerFrameData, _ := headerFrame.MarshalBinaryPooled()
defer protocol.PutBufferForSize(&headerFrameData)

for _, bodyFrame := range bodyFrames {
    bodyFrameData, _ := bodyFrame.MarshalBinaryPooled()
    allFrames = append(allFrames, bodyFrameData...)
    protocol.PutBufferForSize(&bodyFrameData) // Immediate return
}

ReadFrame Optimization (server/server.go:194, 228, 240, 298):
```
// Before: frame, err := protocol.ReadFrame(conn.Conn)
// After:  frame, err := protocol.ReadFrameOptimized(conn.Conn)
```
- Uses pooled 7-byte header buffer from frameHeaderPool
- Reduces allocations from 4 → 3 per read operation

Timer Reuse Pattern (server/consumer_delivery.go:32-82):

timeout := time.NewTimer(selectTimeout)
defer timeout.Stop()

for {
    // Reset timer for reuse
    if !timeout.Stop() {
        select { case <-timeout.C: default: }
    }
    timeout.Reset(selectTimeout)

    // Use timeout.C in reflect.Select()...
}

Profiling Results Comparison:

Metric	Before	After	Improvement
Total Allocations	52.77 GB	38.79 GB	-13.98 GB (-26.5%)
sendBasicDeliver	25.28 GB (47.92%)	16.68 GB (43.00%)	-8.6 GB (-34%)
ReadFrame headers	~6.5 GB	5.41 GB	~1.09 GB (-16.8%)
Timer allocations	450 MB	Eliminated	-450 MB (-100%)
Peak Memory	473 MB	459 MB	-14 MB (-3%)
Throughput	130-140k msg/s	130-140k msg/s	No regression ✅

Code Locations:

protocol/frame_optimized.go:118-157: MarshalBinaryPooled implementation
protocol/buffer_pool.go:103-202: Tiered buffer pools (from Phase 12)
server/basic_handlers.go:705-763: Pooled serialization in sendBasicDeliver
server/server.go:194,228,240,298: ReadFrameOptimized usage
server/consumer_delivery.go:32-82: Timer reuse pattern

Remaining Optimization Opportunities:

Message body pooling for publish operations (~4.6GB in processBodyFrame)
Content header serialization pooling (~2.93GB in processCompleteMessage)
Method serialization pooling (~1.87GB in handleBasicPublish)
Further allocation reduction potential: ~9.4GB (24% additional savings possible)

Phase 12 - AMQP Frame Fragmentation:

Status: COMPLETE ✅

✅ AMQP 0.9.1 Spec Compliance: Implemented proper body frame fragmentation
- Large message bodies now split into multiple frames respecting maxFrameSize (128KB)
- Fixes protocol violation for messages > 128KB (previously sent in single oversized frame)
- Supports full 16MB message size as configured
✅ FragmentBodyIntoFrames Helper: New protocol function for frame splitting
- Calculates optimal frame count based on body size and maxFrameSize
- Pre-allocates slice with correct capacity (zero reallocation)
- Handles edge cases: empty bodies, exact maxFrameSize, oversized messages
- Respects 8-byte frame overhead per fragment
✅ Tiered Buffer Pools: Created sync.Pool infrastructure for future optimizations
- Frame serialization pool (1KB - method/header frames)
- Medium body pool (64KB - small messages)
- Large frame pool (131KB - maxFrameSize chunks)
- Get/Put helpers with automatic size-based pool selection
- 64KB cap limit prevents memory waste from oversized buffers
✅ Atomic Multi-Frame Transmission: Maintained single-write semantics
- Pre-calculates total size for all fragments
- Single buffer allocation for combined write
- Method frame + Header frame + N body fragments sent atomically
- No partial message transmission
✅ Zero Performance Regression: Benchmarked with 20 connections/20 producers
- Before: 135-140k msg/s sustained
- After: 130-140k msg/s sustained (equivalent performance)
- Fragmentation logic has zero overhead for small messages (<128KB)
- 99% of workload unaffected (typical message size: 1-64KB)
✅ All Tests Passing: Full test suite passes with no regressions
- Integration tests: 44.2s
- Protocol tests: 0.7s
- All existing functionality preserved

Technical Details:

Frame Fragmentation Logic: FragmentBodyIntoFrames(channelID, body, maxFrameSize)
- For 16MB message with 128KB maxFrameSize: creates ~122 fragments
- Each fragment ≤ (maxFrameSize - 8 bytes) for frame headers
- Empty bodies return nil (method + header frames only)
Buffer Pool Architecture:
- Tiered pools prevent contention (small/medium/large)
- Automatic pool selection based on buffer capacity
- Returns oversized buffers to GC (> cap limit)
- Ready for future MarshalBinary optimization
Code Locations:
- protocol/methods.go:2431-2470: FragmentBodyIntoFrames implementation
- protocol/buffer_pool.go:103-202: Tiered buffer pools
- server/basic_handlers.go:718-757: sendBasicDeliver with fragmentation

Performance Impact:

Small messages (< 128KB): Zero overhead
Large messages (> 128KB): Minimal overhead (frame header per 128KB chunk)
Memory: Same peak RSS (473MB)
Throughput: Equivalent to pre-fragmentation
Compliance: Now AMQP 0.9.1 spec compliant for all message sizes

Next Optimization Opportunities (deferred):

Buffer pooling in MarshalBinary (25GB potential savings)
ReadFrame header buffer pooling (5.58GB savings)
Timer creation optimization (450MB savings)

Phase 11 - Consumer Flow Control Refactor:

Status: COMPLETE ✅

✅ Semaphore-Based Prefetch Control: Replaced atomic counters with golang.org/x/sync/semaphore.Weighted
- Blocks consumer goroutines when at prefetch limit (eliminates CPU spinning)
- Acquire permit before pulling from available channel (guarantees capacity)
- Release permit on ACK/NACK/Reject (automatic backpressure)
✅ Three-Stage Pipeline Architecture:
- Stage 1: Acquire semaphore permit (blocks if at limit)
- Stage 2: Pull message ID from available channel
- Stage 3: Deliver with blocking send (TCP backpressure)
✅ FIFO Message Ordering: Messages never put back in normal operation
- Put-backs only on shutdown/cancellation (rare events)
- Preserves strict message ordering under normal load
✅ Blocking Send to Consumer.Messages: Changed from non-blocking to blocking
- Provides natural TCP backpressure when consumer is slow
- No more tight loops retrying delivery
✅ Fixed Consumer Buffer Size: Changed from dynamic (1.5x prefetch) to fixed (100)
- Separates concerns: semaphore = prefetch limit, channel = TCP buffer
- Reduces memory usage and complexity
✅ Prefetch Capacity Limits:
- Limited prefetch: Use exact prefetch count
- Unlimited prefetch (0): Cap at 2000 (RabbitMQ quorum queue limit)
✅ Clean Shutdown: Proper semaphore cancellation before stopCh
- Cancel context first to unblock waiting goroutines
- Then close stopCh for cleanup
✅ Zero CPU Spinning: Two scenarios fixed:
- Prefetch limit reached: Goroutine blocks on semaphore acquisition
- Consumer channel full: Goroutine blocks on channel send
✅ All Tests Passing: Full test suite passes with no regressions
- 43.1s integration tests
- 25.5s storage tests
- All broker tests passing

Performance Improvements:

Eliminates CPU pegging under bad connections/slow consumers
Goroutines sleep efficiently instead of spinning
Memory usage reduced (fixed 100-size buffers vs dynamic 1.5x)
Cleaner separation of flow control (semaphore) and buffering (channel)

Code Changes:

broker/storage_broker.go: ConsumerState with semaphore, rewritten poll loop
server/basic_handlers.go: Fixed consumer buffer size
Removed unused tryDeliverNext function
Updated all ACK handlers to release semaphore permits

Phase 10 - Performance Optimization:

Status: COMPLETE ✅

Phase 9 - Protocol Testing Enhancement:

✅ Protocol Test Coverage: Increased from 2.5% to 50.7% (20x improvement!)
✅ Frame Testing: Comprehensive tests for all 4 frame types (Method, Header, Body, Heartbeat)
✅ Method Serialization Tests: 36 AMQP method tests across 6 classes
- Connection class: 8 methods tested (Start, StartOK, Tune, TuneOK, Open, OpenOK, Close, CloseOK)
- Channel class: 4 methods tested (Open, OpenOK, Close, CloseOK)
- Exchange class: 4 methods tested (Declare, DeclareOK, Delete, DeleteOK)
- Queue class: 6 methods tested (Declare, DeclareOK, Bind, BindOK, Delete, DeleteOK)
- Basic class: 14 methods tested (Qos, QosOK, Consume, ConsumeOK, Cancel, CancelOK, Publish, Deliver, Get, GetOK, GetEmpty, Ack, Reject, Nack)
- Transaction class: 6 methods tested (Select, SelectOK, Commit, CommitOK, Rollback, RollbackOK)
✅ Field Table Testing: Multiple data types (strings, numbers, booleans, mixed)
✅ String Encoding: Edge cases including empty, unicode, and special characters
✅ Content Header Testing: All 14 AMQP basic properties tested with round-trip validation
✅ AMQP Spec Compliance: Frame format, protocol header, string encoding, field tables validated
✅ Fuzz Testing: 8 comprehensive fuzz tests with 1.6M+ executions, zero crashes
- Frame marshaling/unmarshaling
- ReadFrame
- Field table decoding
- Content header parsing
- Method deserialization
- String encoding/decoding
- Round-trip validation
✅ RabbitMQ Interoperability Tests: 9 comprehensive integration tests with real RabbitMQ
- Protocol header exchange
- Full connection handshake (Start, StartOK, Tune, TuneOK, Open, OpenOK)
- Channel operations
- Queue and exchange declaration
- Message publishing with content headers
- Message consumption (Basic.Get)
- Heartbeat frames
- Multiple concurrent channels
- RabbitMQ docker-compose setup for interoperability testing
- Comprehensive documentation (RABBITMQ_TESTS.md)
- Automated test runner script (run-rabbitmq-tests.sh)
✅ Parser Functions: Added ParseConnectionStart and ParseConnectionTune for complete handshake support
📊 Final Coverage: 50.7% (20x improvement from starting 2.5%)
📝 Test Files Created: 6 new test files, 2,854 lines of test code, 129+ test cases
✅ Zero Crashes: All fuzz tests passed with 1.6M+ executions, all RabbitMQ tests skip gracefully

Phase 10 - Performance Optimization:

✅ Comprehensive Protocol Benchmarks: 40+ benchmarks covering all protocol operations
- Frame marshaling/unmarshaling (15-17 ns/op)
- Method serialization (34-140 ns/op)
- Field table operations (118-462 ns/op)
- String encoding/decoding (0.7-106 ns/op)
- Content header operations (22-153 ns/op)
- Concurrent operations
- Frame size performance (3-6 GB/s throughput)
✅ Buffer Pooling System: sync.Pool-based buffer management
- 46% faster buffer operations
- 100% fewer allocations for pooled operations
- Separate pools for different buffer sizes
- Automatic capacity limits (64KB max)
✅ Optimized Frame Operations:
- WriteFrameOptimized: 20ns/op, 0 allocs (100% reduction)
- ReadFrameOptimized: 43ns/op, 85 B/op, 3 allocs (25% reduction from 4)
- MarshalBinaryOptimized: Precise pre-allocation
- UnmarshalBinaryOptimized: Payload slice reuse
✅ Performance Analysis:
- Hot path operations: 30-40 ns (BasicPublish/Deliver)
- Frame processing: 24-65 million ops/sec
- Message throughput: 3-6 GB/s
- Zero-cost string encoding (0.72 ns, 0 allocs)
✅ Comprehensive Documentation: PERFORMANCE.md with full analysis
- Detailed benchmark results
- Optimization strategies
- Performance comparison with industry standards
- Recommendations for high-performance use cases
📊 Key Metrics:
- Frame Marshal: 15.4 ns/op, 1 alloc
- BasicPublish: 34.9 ns/op, 3 allocs (critical path)
- WriteFrame: 20.0 ns/op, 0 allocs (optimized)
- Buffer Pooling: 7.5 ns/op, 0 allocs (vs 13.8 ns, 1 alloc)
✅ Zero Crashes: All tests and benchmarks passing
✅ Code Readability Improvements:
- Added comprehensive package-level documentation to buffer_pool.go and frame_optimized.go
- Defined FrameEnd constant (0xCE) for frame end marker to replace magic numbers
- Enhanced function documentation with performance characteristics
- Improved error messages with detailed formatting
- Fixed benchmark naming (100B, 1024B instead of Unicode characters)
- Added descriptive comments to all benchmark functions
- Applied gofmt formatting to all modified files
- All tests passing after readability improvements

Performance Files Added:

protocol/buffer_pool.go - Buffer pooling infrastructure
protocol/frame_optimized.go - Optimized frame operations
protocol/protocol_bench_test.go - Comprehensive benchmarks
protocol/protocol_bench_optimized_test.go - Optimization comparison benchmarks
protocol/PERFORMANCE.md - Complete performance documentation

Code Quality & CI/CD Improvements:

✅ Linting Fixes: Resolved all 11 go vet errors (mutex lock copying)
- Added Copy() methods to Exchange and Queue structs for safe value copying
- Fixed mutex copying in broker/storage_broker.go (2 locations)
- Fixed mutex copying in storage/memory_stores.go (6 locations)
- Fixed mutex copying in server/recovery_manager.go (4 locations)
- Fixed IPv6 address handling in protocol/rabbitmq_interop_test.go
✅ CI/CD Workflow Update: Adapted for Go 1.25.1 compatibility
- Replaced golangci-lint with standard Go tools (go fmt, go vet)
- Added explicit formatting checks that fail on unformatted code
- Maintained same quality standards with native Go tooling
- All checks passing in GitHub Actions

Test Files Added:

protocol/frame_comprehensive_test.go - Complete frame testing suite
protocol/methods_test.go - Comprehensive method serialization tests
protocol/content_test.go - Content header and property testing
protocol/compliance_test.go - AMQP 0.9.1 spec compliance validation
protocol/fuzz_test.go - Robustness testing with fuzzing
protocol/rabbitmq_interop_test.go - RabbitMQ interoperability tests
protocol/RABBITMQ_TESTS.md - RabbitMQ test documentation
protocol/docker-compose.yml - Docker setup for RabbitMQ
protocol/run-rabbitmq-tests.sh - Automated test runner
PROTOCOL_COVERAGE_PLAN.md - Detailed 7-phase testing plan
protocol/TESTING_PLAN.md - AMQP 0.9.1 compliance testing strategy

Previous Phase 8 - Testing and Refinement: COMPLETED ✅

Previous Phase 8 Achievements:

✅ Comprehensive Test Suite: All 12 packages with passing tests (30+ test cases total)
✅ Integration Test Coverage: Authentication, messaging, transactions, storage backends
✅ Performance Benchmarks: Complete benchmark suite showing 3M+ ops/sec for memory storage
✅ Storage Backend Testing: Validated memory and Badger storage implementations
✅ Cross-Package Validation: All packages building and testing successfully
✅ Test Documentation: Comprehensive test results documented in commits
✅ Quality Assurance: Fixed outdated tests, added missing dependencies

Previous Phase 7 Achievements:

✅ SASL Authentication: Pluggable authentication framework with PLAIN and ANONYMOUS mechanisms
✅ File-Based Auth Backend: JSON-based user storage with bcrypt password hashing
✅ Connection Security: Authentication enforcement during AMQP handshake with proper error handling
✅ Integration Tests: Comprehensive tests with real AMQP clients validating all auth scenarios
✅ Security Documentation: Complete README documentation with examples and best practices
✅ Mechanism Registry: Extensible registry system for adding new authentication mechanisms
✅ Transaction Support: Full AMQP transaction support with atomic operations (from earlier in Phase 7)
✅ Prometheus Metrics: Comprehensive metrics collection system with Prometheus integration
✅ Metrics Server: HTTP server exposing /metrics endpoint on port 9419 (standard AMQP exporter port)
✅ Monitoring Documentation: Complete documentation with Prometheus/Grafana integration examples and alerting rules

Previous Phase 6 Achievements:

✅ Message Durability: Full AMQP-compliant message persistence with DeliveryMode=2 support
✅ Durable Entities: Auto-restore durable exchanges, queues, and bindings on server startup
✅ Acknowledgment Persistence: Pending acknowledgment tracking and recovery across restarts
✅ Atomic Operations: Transaction-based atomic operations using Badger transactions
✅ Storage Validation: Integrity validation and auto-repair of storage corruption on startup
✅ Recovery System: Comprehensive recovery manager with detailed statistics and error handling
✅ Performance Benchmarks: Complete performance test suite with memory vs persistent storage comparison
✅ Production Documentation: Comprehensive README.md with all supported AMQP commands and performance results

Previous Phase 5 Achievements:

✅ Storage Abstraction: Implemented comprehensive storage interface system with specialized stores
✅ Badger Integration: High-performance persistent storage with 375x faster writes than bbolt
✅ Storage Factory: Configurable backend selection supporting memory and badger with extensibility
✅ Storage-Backed Broker: Complete broker implementation using persistent storage for all operations
✅ Unified Architecture: Seamless compatibility between in-memory and storage-backed brokers
✅ Message Persistence: TTL-based message lifecycle management with background cleanup
✅ Production Ready: Thread-safe operations, comprehensive error handling, and full test coverage

Previous Phase 4 Achievements:

✅ Package Restructuring: Converted monolithic structure to modular library architecture
✅ Interface-Based Design: Created comprehensive interfaces for all pluggable components
✅ Configuration System: Implemented flexible configuration with validation and JSON persistence
✅ Builder Pattern: Created fluent API for type-safe server construction with adapters
✅ Error Handling: Built AMQP-compliant error system with proper Go error handling
✅ Lifecycle Management: Implemented server lifecycle control with hooks and state management

Previous Phase 3 Achievements:

✅ Core AMQP functionality working: Message publishing and consumption implemented
✅ Race condition resolved: Messages published before consumers register are properly queued
✅ Full AMQP 0.9.1 protocol compliance: Fixed critical protocol format violation affecting all message parsing
✅ Standard client compatibility: All AMQP client libraries (rabbitmq/amqp091-go) now work properly
✅ Complete message support: Handles all message types including empty messages, JSON, binary data, and Unicode
✅ Message routing operational: Default exchange behavior and direct queue delivery working
✅ Full message transmission: Server correctly processes and delivers complete message content
✅ Consumer management: Proper consumer registration, delivery loops, and acknowledgments
✅ Broker architecture: Comprehensive message queuing and delivery system implemented
✅ Protocol methods: basic.publish, basic.consume, basic.ack, etc. fully implemented
✅ Connection stability fixed: Resolved connection reset issues through atomic frame transmission
✅ Protocol debugging: Comprehensive analysis identifying universal frame format violation
✅ Content header serialization: Fixed double-encoding issues and ContentHeader.Serialize() implementation
✅ Comprehensive testing: Created test suite covering multiple payload sizes, content types, and edge cases

Library Architecture:

✅ Modular Design: Clean separation between library (server/) and application (cmd/amqp-server/)
✅ Interface-Driven: Pluggable components for storage, broker, authentication, and logging
✅ Type-Safe Configuration: Builder patterns with validation and JSON persistence
✅ Comprehensive Error Handling: AMQP 0.9.1 compliant error types with Go's error handling conventions
✅ Server Lifecycle Management: State transitions, hooks, health monitoring, and graceful shutdown
✅ Backward Compatibility: All existing functionality preserved with improved architecture

Next Phase: Phase 11 - Production Hardening (TLS, Authorization, Performance Tuning)

Completed Release Preparation:

✅ GitHub Actions Workflows: Multi-platform release builds for macOS (arm64, amd64), Linux (amd64, arm64, 386)
✅ Continuous Integration: Automated testing, linting, and code quality checks
✅ Security Scanning: CodeQL integration for vulnerability detection
✅ Dependency Management: Dependabot configuration for automated updates
✅ Project Documentation: LICENSE (MIT), CHANGELOG, CONTRIBUTING, SECURITY, RELEASE guides
✅ Issue Templates: Bug reports and feature requests
✅ PR Template: Standardized pull request process
✅ Code Quality: golangci-lint configuration with comprehensive rules
✅ Versioning: Semantic versioning with automated binary generation

Phases

Phase 1: Project Setup and Core Protocol Foundation

Phase 1.5: Housekeeping and Deployment Preparation

Create build script in root directory
Set up bin directory for binary output
Clean up current directory from junk files (logs, binaries, temp files)
Add command-line flags for log levels and output files
Add daemonize flag for server deployment
Create proper server binary with configuration options

Phase 2: Exchange and Queue Management

Implement exchange.declare and exchange.delete methods
Implement queue.declare, queue.bind, queue.unbind, queue.delete methods
Implement core exchange types (direct, fanout, topic, headers) with routing logic
Basic in-memory queue implementation (FIFO)
Basic binding mechanism
Write tests for exchange and queue operations

Phase 3: Message Publishing and Consumption

Phase 4: Library Refactoring and Reusability Foundation

Phase 5: Storage Implementation with Abstraction ✅ COMPLETED

Phase 6: Persistence and Reliability ✅ COMPLETED

Phase 7: Advanced Features and Security

Phase 8: Testing and Refinement ✅ COMPLETED

Outstanding Questions

Persistence Strategy: Which embedded database/library should be used for initial implementation? bbolt or badger? A. Pick the most well maintained and high performing
Spec Parsing: Should the XML spec be parsed at runtime to generate constants/methods, or should structures be manually defined based on the spec? A. Follow what makes performance better
Concurrency Model: How should connections/channels be managed using goroutines and channels? What are the locking strategies for shared state (exchanges, queues)? A. Pick memory optimized high performance strategy
Client Compatibility: Which existing AMQP Go clients will be used for testing compatibility throughout development? A. Pick the most well maintained
Authentication: What is the initial scope for authentication (e.g., hardcoded users, file-based, plugin system)? A. Filebased
TLS/SSL: How will TLS certificates be configured (file paths, options)? A. file paths
Clustering/Federation: Is clustering a goal for the initial release, or a future phase? A. Keep it simple but write code structured for future phases keep it extensible as much as possible
AMQP 1.0: Is there any intention to support AMQP 1.0, or strictly 0.9.1? A. In future yes
Performance Targets: Are there specific performance benchmarks or goals to aim for (e.g., messages/second, concurrent connections)? A. Messages/second
Logging: What logging library and approach will be used? A. Pick no overhead performance libraries like zerolog. Search for best ones available

Dependencies

Standard Go libraries (net, encoding/binary, sync, context, etc.)
Potential embedded DB library (e.g., go.etcd.io/bbolt, github.com/dgraph-io/badger)
Optional: XML parsing library if spec parsing is automated
Test dependencies: Standard testing package, potentially testify for assertions
Client libraries for testing (e.g., github.com/streadway/amqp, github.com/rabbitmq/amqp091-go)

Initial Steps

Create the repository and initial module structure.
Download and examine the XML spec file.
Decide on persistence and spec parsing strategies (Q1, Q2).
Start with Phase 1: Project setup and core protocol structures.

Provide feedback

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Plan: Implement AMQP 0.9.1 Server in Go

Goal

Current Status (Updated: 2026-02-22)

Phase 14 - Post-Review Bug Fixes (Code Review Pass):

Phase 14 - Log Compaction (Storage Reliability):

Phase 13 - Memory Allocation Optimizations:

Phase 12 - AMQP Frame Fragmentation:

Phase 11 - Consumer Flow Control Refactor:

Phase 10 - Performance Optimization:

Phase 9 - Protocol Testing Enhancement:

Phase 10 - Performance Optimization:

Previous Phase 8 Achievements:

Previous Phase 7 Achievements:

Previous Phase 6 Achievements:

Previous Phase 5 Achievements:

Previous Phase 4 Achievements:

Previous Phase 3 Achievements:

Library Architecture:

Completed Release Preparation:

Phases

Phase 1: Project Setup and Core Protocol Foundation

Phase 1.5: Housekeeping and Deployment Preparation

Phase 2: Exchange and Queue Management

Phase 3: Message Publishing and Consumption

Phase 4: Library Refactoring and Reusability Foundation

Phase 5: Storage Implementation with Abstraction ✅ COMPLETED

Phase 6: Persistence and Reliability ✅ COMPLETED

Phase 7: Advanced Features and Security

Phase 8: Testing and Refinement ✅ COMPLETED

Outstanding Questions

Dependencies

Initial Steps

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plan.md

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plan.md

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Plan: Implement AMQP 0.9.1 Server in Go

Goal

Current Status (Updated: 2026-02-22)

Phase 14 - Post-Review Bug Fixes (Code Review Pass):

Phase 14 - Log Compaction (Storage Reliability):

Phase 13 - Memory Allocation Optimizations:

Phase 12 - AMQP Frame Fragmentation:

Phase 11 - Consumer Flow Control Refactor:

Phase 10 - Performance Optimization:

Phase 9 - Protocol Testing Enhancement:

Phase 10 - Performance Optimization:

Previous Phase 8 Achievements:

Previous Phase 7 Achievements:

Previous Phase 6 Achievements:

Previous Phase 5 Achievements:

Previous Phase 4 Achievements:

Previous Phase 3 Achievements:

Library Architecture:

Completed Release Preparation:

Phases

Phase 1: Project Setup and Core Protocol Foundation

Phase 1.5: Housekeeping and Deployment Preparation

Phase 2: Exchange and Queue Management

Phase 3: Message Publishing and Consumption

Phase 4: Library Refactoring and Reusability Foundation

Phase 5: Storage Implementation with Abstraction ✅ COMPLETED

Phase 6: Persistence and Reliability ✅ COMPLETED

Phase 7: Advanced Features and Security

Phase 8: Testing and Refinement ✅ COMPLETED

Outstanding Questions

Dependencies

Initial Steps