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Changelog

All notable changes to IZI SIPREC will be documented in this file.

[1.3.0] - 2026-07-02

Added

  • Azure SAS-Token Authentication: Azure Blob recording storage can now authenticate with a container-scoped SAS token via RECORDING_STORAGE_AZURE_SAS_TOKEN. This is the recommended, least-privilege method — a SAS token can be limited to a single container with create/write permissions and an expiry, unlike an account key which grants full access to the entire storage account. See docs/configuration.md → "Azure Blob Storage Authentication".
  • Azure Auth Validation: Startup validation ensures exactly one Azure auth method is configured when Azure storage is enabled, and logs a warning when the account key is used.

Changed

  • Azure SDK Migration: Replaced the deprecated github.com/Azure/azure-storage-blob-go (v0.15.0, end-of-life) with the modern github.com/Azure/azure-sdk-for-go/sdk/storage/azblob. Blob operations now use the client-based API. Existing deployments using RECORDING_STORAGE_AZURE_ACCESS_KEY continue to work unchanged.

Removed

  • Dependencies github.com/Azure/azure-storage-blob-go and github.com/Azure/azure-pipeline-go.

[1.2.4] - 2026-06-12

Security

  • Removed Committed Encryption Key: Deleted an encryption key file that had been committed to the repository
  • Hardened .gitignore: Keys, certificates, local environment files, and build artifacts are now excluded from version control

Added

  • Async STT Job API: Queued transcription jobs exposed via /api/stt/submit, /api/stt/jobs, /api/stt/jobs/{id}, /api/stt/stats, /api/stt/metrics, and /api/stt/queue/purge
  • Configuration API: Hot-reload management endpoints at /api/config, /api/config/validate, /api/config/reload, and /api/config/reload/status
  • RBAC Enforcement: Optional role-based access control for HTTP API endpoints, enabled via AUTH_RBAC_ENABLED=true (requires authentication and database persistence)
  • SMTP Email Alerting: The alerting email channel now delivers real SMTP mail with auto, implicit (SMTPS), starttls, and none TLS modes
  • Alert Delivery Metrics: Notification channels report real delivery success/failure metrics
  • Encryption Key Backup/Restore: Encryption keys can be exported to and restored from password-protected backups
  • AWS Secrets Manager Lookup: Provider credentials can be resolved from AWS Secrets Manager
  • DNS & Load Balancer Failover: Route 53 and GCP DNS failover plus GCP load balancer failover support in the backup/disaster-recovery subsystem
  • Database Restore: Disaster-recovery database restore now uses pg_restore for PostgreSQL dump archives

Fixed

  • STUN Client RFC 5389 Compliance: External IP discovery now builds and parses STUN messages per RFC 5389
  • Hot-Reload Deep Copy: Configuration hot-reload performs a proper deep copy of the active configuration, preventing shared-state mutation between reloads

Removed

  • Roughly 850 dead/unused functions across the codebase
  • Stale test reports, planning notes, ad-hoc test scripts, and scenario files from the repository root

[1.2.0] - 2026-03-17

Added

  • Per-Stream G.729 Decoder: Each RTP stream now has its own dedicated G.729 decoder instance

    • Eliminates cross-call state leakage and race conditions from shared decoder pool
    • Decoder state is properly isolated per goroutine for thread safety
    • Added ConcealPackets() method for proper PLC that advances decoder state

  • SSRC Validation & Locking: First RTP packet locks the expected SSRC for the stream

    • Packets with mismatched SSRC are dropped to prevent stale traffic from port reuse
    • Protects against cross-talk from delayed packets on recycled ports
    • Per-stream mismatch counters logged at stream end for diagnostics

  • SSRC Correction Mechanism: Automatic SSRC switching when the locked SSRC goes silent

    • Handles "first-packet poisoning" after restart when stale packet locks wrong SSRC
    • Handles "silent SSRC change" when SBC changes SSRC during hold/unhold without signaling
    • Safety guards: requires 50+ packets from alternate SSRC AND 30+ consecutive non-locked packets
    • Blocked during hold state or RTP suspended state to prevent accepting stale traffic

  • Port Allocation Cooldown: Recently freed ports are avoided to prevent stale RTP crosstalk

    • Fresh (never-used) ports preferred over recently released ports
    • Cooldown ports used as fallback only when all fresh ports are exhausted
    • Prevents new calls from receiving delayed packets from previous calls

  • SIPREC Forwarder Resilience: SIPREC forwarders now survive RTP timeout instead of terminating

    • Enter RTPSuspended state when RTP times out (SBC stopped RTP without signaling)
    • Wait for BYE signal from SIP layer for proper cleanup
    • SSRC correction blocked during suspended state to prevent accepting stale traffic

  • ResetRemoteSSRC API: SIP signaling events (re-INVITE, UPDATE) reset SSRC lock

    • Called on re-INVITE with SDP to allow new SSRC from SBC
    • Called on hold/resume transitions to handle media renegotiation
    • Clears RTPSuspended state so forwarder is fully active for new stream

Fixed

  • gosec Security Alerts: Fixed all remaining security scanner warnings
    • G104: Added explicit error ignoring with #nosec comments for cleanup operations
    • G602: Refactored slice access patterns to avoid index bounds warnings

Technical

  • Per-goroutine G729StreamDecoder scoped to RTP forwarding lifetime
  • Atomic RTPSuspended flag for lock-free state checking in hot path
  • Port manager tracks recently freed ports with timestamp for cooldown logic
  • All changes validated with race detection and memory leak testing
  • 50 iterations × 100 packets memory test shows 0 goroutine leaks, 0 MB memory growth

[1.1.1] - 2026-03-17

Fixed

  • G.729 DTX Audio Desync: Fixed channel audio desync and garbled recordings with G.729 codec

    • DTX (Discontinuous Transmission) silence periods no longer trigger excessive PLC silence insertion
    • Uses RTP timestamp gaps to distinguish real packet loss from DTX silence suppression
    • Reduced maxPLC from 100 packets (2s) to 10 packets (200ms) to prevent recording inflation
    • Fixed sequence tracking for reordered packets to prevent backwards tracking

  • G.729 Decoder Stability: Added oscillation detection for unstable synthesis filter

    • Detects 2kHz square wave artifacts (>50% railed samples with >25% sign changes)
    • Replaces corrupt decoder output with silence to prevent harsh buzzing/distortion

  • WAV Recording Reliability: Improved recording file handling

    • WAV files are now finalized on RTP goroutine exit ensuring playable recordings
    • WAV reader handles unfinalized files by inferring data size from remaining file length

Added

  • Buffered STT Pipe: Replaced unbuffered io.Pipe with buffered pipe (4KB) for STT streaming

    • Decouples RTP handler from STT backpressure to prevent audio processing stalls
    • Non-blocking writes prevent RTP packet loss during temporary STT slowdowns
    • Automatic buffer overflow handling drops oldest data to maintain real-time processing

  • Jitter Buffer: Added per-leg jitter buffer for RTP packet reordering

    • Reorders out-of-order packets by sequence number before decoding
    • Configurable buffer size (default: 5 packets) and max delay (default: 60ms)
    • Duplicate packet detection and filtering
    • PLC callback for lost packet notification

  • WAV Start-Time Alignment: Added wall-clock alignment for multi-leg WAV combining

    • Records first RTP packet timestamp for each recording leg
    • CombineWAVRecordingsAligned() pads earlier-starting legs with silence
    • Ensures both channels are wall-clock synchronized in stereo output

Technical

  • Track lastDecodedPCMSize for accurate PLC silence length calculation
  • DTX detection uses 60ms RTP timestamp threshold (3x normal 20ms packet interval)
  • All changes validated with race detection enabled
  • New test coverage for JitterBuffer and BufferedPipe components

[1.1.0] - 2026-03-15

Added

  • Lawful Intercept Package (pkg/lawfulintercept/): Complete implementation for lawful intercept requirements

    • Manager: Intercept lifecycle management with warrant verification and content delivery
    • DeliveryClient: Secure LEA delivery with mutual TLS, batching, retries, and exponential backoff
    • AuditLogger: Tamper-evident audit logging with buffered writes and log rotation
    • WarrantVerifier: External warrant verification with response caching
    • ContentEncryptor: Hybrid RSA-OAEP + AES-256-GCM encryption for intercepted content
    • Comprehensive audit event types: system start/stop, intercept started/revoked/expired, content delivered, warrant verified/failed

  • Resource Management Package (pkg/resources/): Enterprise resource control and limits enforcement

    • Manager: Central resource manager coordinating all resource limits
    • WorkerPool: Bounded goroutine pool with panic recovery and configurable sizing
    • MemoryMonitor: Memory limit enforcement with automatic GC triggers and detailed stats
    • RTPLimiter: Concurrent RTP stream limiting with atomic operations and wait-for-slot support
    • Resource exhaustion callbacks for alerting and load balancing integration

Performance

  • Lock-free RTP timestamp tracking: Replaced mutex-protected timestamp with atomic int64 operations
  • Optimized ShardedMap hashing: Inline FNV-1a hash eliminates allocations in hot path
  • Read-write lock optimization: Changed ProcessingManager to use RWMutex for read-heavy workloads
  • Memory leak fix: Fixed slice memory leak in STT result buffer management

Changed

  • Go 1.25 Requirement: Updated minimum Go version from 1.24 to 1.25
  • Security Hardening: Fixed all gosec security scan alerts (30 issues resolved)
    • Fixed slice bounds issues (G602) in STUN handling
    • Fixed path traversal concerns (G703) with filepath.Clean()
    • Fixed directory permissions (G301) from 0755 to 0750
    • Fixed file permissions (G306) from 0644 to 0600
    • Documented context.Background() usage (G118) for long-running services

Technical

  • Full test coverage with race detection for all new packages
  • Atomic operations throughout for thread-safe concurrent access
  • Integration with existing config system via ResourceConfig, LawfulInterceptConfig
  • Fixed potential goroutine leak in AnalyticsWebSocketHandler with proper Stop() method
  • Fixed unbounded goroutine spawning in ResourceManager cleanup with semaphore limiting
  • Added buffered channel to TranscriptionHub broadcast to prevent sender blocking

[1.0.2] - 2026-02-26

Added

  • G.729 Codec Support: Native G.729 (CS-ACELP) decoding using bcg729 library
    • ITU-T G.729 compliant decoder via github.com/pidato/audio/g729 bindings
    • Stateful decoder pool for maintaining decoder state across RTP packets
    • Support for G.729A (Annex A) which is decoder-compatible
    • Support for G.729B SID frames (comfort noise)

Fixed

  • G.729 Audio Quality: Resolved noisy/distorted audio in G.729 recordings

    • Replaced custom decoder with ITU-T compliant bcg729 implementation
    • Added per-SSRC stateful decoding for proper audio reconstruction
    • Fixed audio clipping issues with proper gain scaling

  • Race Condition in RTPForwarder: Fixed concurrent access to codec fields

    • Added codecMutex to protect codec configuration
    • Added thread-safe GetCodecInfo() method
    • Updated RTP processing to use synchronized access

Documentation

  • Added G.729/bcg729 build requirements to README
  • Added installation instructions for Ubuntu/Debian, macOS, and RHEL/CentOS

Requirements

[1.0.1] - 2026-02-17

Added

  • Oracle SBC SIPREC XML Extension Support: Complete parsing of Oracle/ACME Packet proprietary XML extensions

    • Extract UCID (Universal Call ID) from <apkt:ucid> element in SIPREC metadata body
    • Extract caller origination flag from <apkt:callerOrig> element
    • Extract calling party identification from <apkt:callingParty> participant extensions
    • Support for Oracle's ACME Packet XML namespace (http://acmepacket.com/siprec/extensiondata)
    • New OracleExtensionData struct for structured access to Oracle-specific metadata
    • New helper functions: ExtractOracleExtensions(), GetOracleSessionExtensions(), GetOracleParticipantExtensions(), IdentifyCallingParticipant()
    • UCID extraction priority: XML body extensions take precedence over SIP headers

  • SIPREC Stream Labels: Added stream label information to AMQP transcription messages

    • Stream labels now included in transcription metadata for caller/agent identification
    • Enhanced ResolveStreamParticipant() with multiple fallback strategies

Fixed

  • Race Condition Fixes: Comprehensive thread-safety improvements across the codebase
    • Fixed provider map race condition in pkg/stt/provider.go with dedicated mutex
    • Fixed session metadata race in pkg/stt/transcription.go by returning/storing copies instead of references
    • Fixed global state race in cmd/siprec/main.go with initialization flag and snapshot pattern in signal handler
    • All fixes validated with go test -race

Enhanced

  • Vendor Documentation: Updated docs/vendor-integration.md with comprehensive Oracle SBC XML extension documentation
    • Added XML Extension Data table documenting apkt:ucid, apkt:callerOrig, apkt:callingParty
    • Added example Oracle SIPREC XML metadata
    • Added UCID Extraction Priority section explaining data source precedence

Technical

  • Added comprehensive unit tests for Oracle extension extraction in pkg/siprec/types_test.go
  • Tests cover: UCID extraction, calling party identification, session/participant extensions, priority ordering

[1.0.0] - 2026-01-30

Major Release - IZI SIPREC

This is the first stable release of IZI SIPREC, marking production readiness after extensive testing and validation.

Added

  • Full OPUS and G.722 Codec Support: Complete implementation of OPUS (RFC 6716) and G.722 (ITU-T G.722) decoders for recording calls using these codecs

    • OPUS decoder supporting SILK, CELT, and Hybrid modes
    • G.722 Sub-band ADPCM decoder with QMF synthesis filter
    • Fixes issue where calls using OPUS codec failed to record

  • Multi-Vendor Compatibility: Validated with all major SBC vendors

    • Cisco CUBE
    • Avaya Session Manager
    • Oracle SBC
    • Genesys Cloud

  • Production Load Testing: Validated at scale

    • 500 concurrent multi-vendor calls with 100% success rate
    • Zero errors across Cisco, Avaya, Oracle, and Genesys scenarios

  • Load Testing Validation: Comprehensive load testing with documented results

    • Validated up to 20,000 concurrent calls with 100% success rate
    • 6,000 concurrent 5-minute calls over TCP with zero failures
    • Memory efficiency: ~55 KB per concurrent call (signaling only)
    • CPU efficiency: Linear scaling at ~0.001% per concurrent call
    • New SIPp test scenarios in test/sipp/ directory

  • Multi-Format Audio Recording: Support for multiple audio output formats via FFmpeg encoding

    • Supported formats: WAV, MP3, Opus, OGG, MP4/M4A (AAC), FLAC
    • Configurable bitrate for lossy formats (MP3, Opus, AAC)
    • Quality settings for VBR encoding
    • Automatic fallback to WAV if FFmpeg is unavailable
    • Batch encoding support for converting existing recordings
    • New environment variables: RECORDING_FORMAT, RECORDING_MP3_BITRATE, RECORDING_OPUS_BITRATE, RECORDING_QUALITY

  • Per-Call Timeout Configuration: Override global timeouts on a per-recording basis

    • SIP header support: X-Recording-Timeout, X-Recording-Max-Duration, X-Recording-Retention
    • SIPREC metadata support: siprecTimeout, siprecMaxDuration, siprecRetention elements
    • Priority order: SIP headers > SIPREC metadata > global configuration
    • Timeout source tracking for debugging and audit

  • Enhanced Audit Trail with SIP Headers: Complete SIP header capture for compliance

    • All SIP-related audit events now include full header information
    • Core headers: Method, Request-URI, From, To, Call-ID, CSeq, Via, Contact
    • Authentication headers: Authorization, Proxy-Authorization (auto-redacted)
    • Routing headers: Route, Record-Route
    • Session headers: Allow, Supported, Require, User-Agent, Server
    • Transport info: Protocol, remote/local addresses
    • Custom/vendor headers captured in dedicated map

  • Leg-Merge Regression Tests: pkg/sip/custom_server_test.go now exercises the WAV combiner to ensure multi-leg SIPREC recordings produce the expected multi-channel output and metadata path.

Documentation

  • Recording Format Reference: README now explains how SIPREC preserves multi-channel WAV layouts from the SDP offer and how to keep both legs in a single stereo file.
  • Configuration Guide: Added RECORDING_COMBINE_LEGS so operators can explicitly control whether the SRC legs are merged into a single multi-channel WAV.
  • Audio Format Configuration: New section documenting supported formats, codec options, and FFmpeg requirements.
  • Per-Call Timeout Configuration: New section documenting SIP headers and SIPREC metadata for per-call overrides.
  • Audit Trail & SIP Headers: New section documenting captured headers, log format, and filtering examples.

Fixed

  • Recording Reliability: Audio capture is now decoupled from the STT pipeline. Transcription crashes or disabled providers no longer produce zero-byte recordings or keep analytics publishers running past BYE. The server logs when an STT stream shuts down and completes recording/cleanup normally.

[0.0.34] - 2025-11-09

Added

  • Whisper STT Provider: On-premise speech-to-text using OpenAI's open-source Whisper CLI
    • Full integration with existing STT provider architecture
    • Support for 5 model sizes (tiny, base, small, medium, large)
    • Circuit breaker protection for resilience
    • Multiple output format support (JSON, TXT, VTT, SRT, TSV, verbose_json)
    • Injectable runner pattern for comprehensive testability
    • 23 comprehensive tests covering initialization, formats, errors, edge cases, and advanced scenarios
  • Whisper Performance & Monitoring: Production-grade observability and resource management
    • 4 Prometheus metrics: CLI execution duration histogram, temp file disk usage gauge, timeout counter, output format counter
    • Aggregate disk usage tracking with increment/decrement pattern for concurrent operations
    • Concurrent call rate limiting with semaphore-based control
    • Auto mode limits to CPU core count; manual override for GPU servers
    • Binary validation with version detection (gracefully handles remote servers)
  • Remote Deployment Support: Flexible architecture for distributed Whisper installations
    • SSH wrapper support for remote GPU servers
    • HTTP API integration for dedicated Whisper farms
    • RabbitMQ/queue-based dispatcher support for large-scale deployments
    • Configurable timeout handling for network latency
  • Comprehensive Documentation: Complete setup and reference guides
    • Dedicated step-by-step setup guide (docs/whisper-setup.md)
    • 5 deployment scenarios: local CPU/GPU, Docker, SSH wrapper, HTTP API, dedicated farm
    • Technical reference with configuration, metrics, GPU acceleration, troubleshooting
    • Model selection guide with performance characteristics
    • Best practices for production hardening and operations
  • Comprehensive Test Coverage for GDPR Deletion: 55+ tests across 5 test files
    • Backup storage scheme-aware deletion tests (13 tests)
    • Recording storage manifest tracking tests (15 tests)
    • GDPR service deletion tests (7 unit tests + 7 integration tests)
    • Encrypted recording writer tests (8 tests)
    • Complete end-to-end GDPR erase flow integration tests
  • CallDataRepository Interface: Abstraction for GDPR service database operations
    • Enables proper mocking and testing without database dependencies
    • Defines contract for GetSessionByCallID, GetCDRByCallID, DeleteCallData, etc.
    • Improves testability and maintainability of GDPR compliance features

Enhanced

  • Storage Deletion Routing: Improved scheme-aware deletion logic
    • Better handling of ambiguous schemes (e.g., "gcs" vs "gs")
    • Exact match support for location identifiers
    • URL format matching with "scheme://" prefix
    • Prefix matching with non-letter boundary detection
  • Test Infrastructure: Mock implementations for all storage and repository interfaces
    • Realistic simulation of manifest file operations
    • Proper cleanup verification in integration tests
    • Edge case coverage (empty paths, missing files, malformed JSON)

Fixed

  • Storage matching logic now correctly distinguishes between similar scheme prefixes
  • GDPR service tests properly mock repository interface methods
  • Recording storage mock now simulates manifest deletion behavior

Technical

  • All tests passing with comprehensive coverage of edge cases
  • Integration tests verify complete upload → track → erase → verify flow
  • Concurrent operation tests ensure thread safety
  • SIPP tests confirm no regression in core functionality

[0.0.33] - 2025-11-09

Added

  • Centralized Version Management: New pkg/version package for consistent version reporting
    • Single source of truth for application version (0.0.33)
    • UserAgent() function for HTTP client headers
    • ServerHeader() function for SIP and HTTP server headers
  • SIP Server Header: All SIP responses now include Server: siprec/0.0.33 header
    • Automatically added to 100 Trying, 180 Ringing, 200 OK, and all other responses
    • Helps with debugging and protocol compliance tracking
  • HTTP Server Header: All HTTP responses now include Server: siprec/0.0.33 header
    • Applied via middleware to health, metrics, and status endpoints
    • Consistent server identification across all HTTP responses
  • User-Agent Header: HTTP clients now send User-Agent: siprec/0.0.33
    • Applied to STUN fallback HTTP requests for external IP detection
    • Improves server identification in external API calls

Fixed

  • SIPREC Validation: Treat missing state attribute as warning instead of fatal error
    • While RFC 7866 §4.2 requires the state attribute, many real-world implementations omit it
    • Messages without state attribute are now accepted with a warning logged
    • State defaults to "active" in responses for better interoperability
    • Added comprehensive test coverage for edge cases:
      • Missing state without reason
      • Missing state with valid reason
      • Missing state with invalid reason
      • Empty state skipping state-specific validations

Enhanced

  • Metrics Endpoint: Build info now reports actual version (0.0.33) instead of hardcoded "1.0.0"
  • Status Endpoint: Version field now dynamically reports current version from version package

[0.2.3] - 2025-10-19

Added

  • Complete MySQL/MariaDB Database Support: Optional persistence layer with build tags
    • 30+ CRUD operations for sessions, participants, streams, transcriptions, CDRs
    • Full-text search across all entities
    • User management and API key authentication
    • GDPR-compliant data deletion operations
  • Multi-Cloud Storage Support: Automatic recording archival
    • AWS S3 with lifecycle policies
    • Google Cloud Storage integration
    • Azure Blob Storage support
  • Real-time Analytics Platform: Elasticsearch-powered analytics
    • Sentiment analysis and keyword extraction
    • Compliance monitoring and alerting
    • WebSocket streaming for live updates
    • Audio quality metrics (MOS scoring)
  • Extended STT Provider Support: 7 providers with intelligent routing
    • ElevenLabs and Speechmatics integration
    • Language-based provider routing
    • Automatic failover with health monitoring
  • Enterprise Features:
    • PCI DSS compliance mode with automatic security hardening
    • OpenTelemetry integration for distributed tracing
    • Multi-channel alerting (email, Slack, webhook)
    • Clustering support with leader election
    • Automated backup and recovery
    • Performance monitoring and auto-tuning
  • Advanced Audio Processing:
    • Spectral noise suppression
    • Automatic Gain Control (AGC)
    • Echo cancellation with double-talk detection
    • Audio fingerprinting for duplicate detection
  • Comprehensive Testing Suite:
    • Unit, integration, and E2E tests
    • Coverage reporting with HTML output
    • MySQL-specific test targets

Enhanced

  • Documentation completely updated with all features
  • Build system with optional MySQL support via build tags
  • Circuit breaker patterns for all external services
  • WebSocket implementation with proper cleanup
  • AMQP messaging with connection pooling and TLS

Fixed

  • Test compilation errors in audio processing
  • WebSocket null pointer dereferences
  • Parser namespace issues in tests
  • Memory leaks in audio processing pipeline
  • Build errors with missing dependencies

[0.3.0] - 2025-07-01

Added

  • Pause/Resume Control API: Comprehensive REST API for controlling recording and transcription
    • Real-time pause and resume of individual sessions or all active sessions
    • Granular control: pause recording, transcription, or both independently
    • Secure API key authentication with configurable access control
    • Per-session and global pause/resume operations
    • Status monitoring with pause duration metrics
  • PII Detection & Redaction: Automatic detection and redaction of personally identifiable information
    • Real-time detection of SSNs, credit card numbers, phone numbers, and email addresses
    • Advanced validation using Luhn algorithm for credit cards and SSN format validation
    • Configurable redaction with format preservation options
    • Transcription filtering with real-time PII redaction
    • Audio timeline marking for post-processing PII redaction
    • Thread-safe processing with race condition prevention
    • Integration with WebSocket and AMQP transcription delivery
  • Thread-Safe Stream Control: Implementation of pausable I/O streams
    • PausableWriter for recording streams that drops data when paused
    • PausableReader for transcription streams that blocks reads when paused
    • Mutex-protected operations for concurrent safety
  • Enhanced Session Management: Extended RTPForwarder with pause/resume state and PII audio marking
    • Thread-safe pause/resume methods with proper synchronization
    • Real-time status tracking with pause timestamps and duration
    • Seamless integration with existing STT providers
    • PII audio marker integration for timeline-based redaction
  • Monitoring and Metrics: Comprehensive observability for pause/resume and PII operations
    • Prometheus metrics for pause/resume events and durations
    • PII detection metrics and performance monitoring
    • Structured logging with session context and operation details
    • Real-time status endpoints for monitoring active sessions
  • Configuration System: Full environment variable and JSON configuration support
    • Configurable authentication, timeouts, and default behaviors
    • Optional maximum pause duration with auto-resume capability
    • Granular control over recording vs transcription pause behavior
    • Comprehensive PII detection configuration options

Enhanced

  • API Architecture: Extended HTTP server with new REST endpoints
  • Session Store: Enhanced ShardedMap with Keys() method for session enumeration
  • Documentation: Comprehensive API documentation with usage examples
  • Testing: Complete unit and integration test coverage for all pause/resume functionality

Technical

  • Thread Safety: All operations use proper mutex synchronization
  • Performance: Minimal overhead with immediate effect pause/resume operations
  • Reliability: Non-blocking operations that don't affect other session functionality
  • Security: Optional API key authentication with audit logging

[0.2.0] - 2025-05-23

Added

  • End-to-End Encryption: Optional AES-256-GCM and ChaCha20-Poly1305 encryption for audio recordings and session metadata
  • Automatic Key Management: Secure key generation, rotation, and storage with configurable intervals
  • Multiple Key Stores: File-based persistent storage and memory-based volatile storage options
  • Encrypted File Format: Custom .siprec format with encryption headers and chunk-based storage
  • Session Isolation: Independent encryption contexts for each recording session
  • Key Rotation Service: Automated background service for key rotation with configurable intervals
  • Comprehensive Encryption Tests: Unit, integration, and performance tests for all encryption functionality
  • Encryption Documentation: Complete guide with usage examples, security considerations, and best practices
  • Configuration Integration: Full environment variable configuration with validation and defaults
  • Docker Integration: Enhanced Docker containerization with multi-stage builds and testing
  • STT Provider Integration: Comprehensive testing for Amazon Transcribe, Azure Speech, Google Speech, and Mock providers

Enhanced

  • Security: Added forward secrecy through automatic key rotation
  • Testing Suite: Expanded with integration tests for STT providers and comprehensive unit tests
  • Documentation: Updated with encryption capabilities and configuration options
  • Docker Support: Production-ready multi-stage builds with security hardening
  • Build System: Enhanced Makefile with cross-platform support and quality assurance

Security

  • Authenticated Encryption: AEAD modes prevent tampering with encrypted data
  • Secure Defaults: Strong cryptographic parameters and secure key generation
  • Session Security: Per-session encryption contexts with audit logging capabilities

[0.1.0] - 2025-04-17

Added

  • Initial release with core SIPREC server functionality
  • RFC 7245 compliant session redundancy implementation
  • SIP Dialog replacement support via Replaces header
  • TLS and SRTP security for signaling and media
  • Concurrent session handling with sharded maps
  • Memory optimization with RTP buffer pooling
  • Production-ready Prometheus metrics
  • Basic health check API
  • Docker and docker-compose support
  • Comprehensive testing suite

Optimized

  • Concurrent session handling using sharded maps in pkg/sip/handler.go
  • Reduced lock contention for better scaling with many concurrent calls
  • Efficient memory usage with buffer pooling for RTP packets
  • Better performance under high load with concurrent processing

[Unreleased]

Added

  • SIP_HOST Configuration: Added configurable SIP server bind address
    • Set bind address via SIP_HOST environment variable (default: "0.0.0.0")
    • Affects Via and Contact headers in SIP responses
    • Enables binding to specific network interfaces

Enhanced

  • Infrastructure Package Integration: Fixed and integrated critical monitoring and resilience systems
    • pkg/metrics: Fixed broken metrics system - was being referenced but never initialized
      • Added metrics.Init() and metrics.InitEnhancedMetrics() calls
      • Prometheus endpoint now properly exposes all RTP, SIP, STT, and AMQP metrics
      • Fixed null/empty metrics response issue
    • pkg/circuitbreaker: Integrated circuit breaker protection for all STT providers
      • Wrapped all 7 STT providers (Google, Deepgram, Azure, Amazon, OpenAI, Speechmatics, ElevenLabs)
      • Automatic failure detection and recovery
      • Prevents cascading failures when providers are unavailable
      • Configurable thresholds and timeout periods
    • pkg/performance: Integrated real-time performance monitoring
      • Memory usage tracking with automatic GC triggering
      • Goroutine leak detection
      • CPU usage monitoring with configurable limits
      • Proper initialization and graceful shutdown
    • pkg/auth: Integrated authentication and authorization system
      • JWT token authentication with configurable expiry
      • API key authentication for service-to-service communication
      • Simple in-memory user management with role-based permissions
      • Configurable admin credentials via environment variables
      • Disabled by default, enable via AUTH_ENABLED=true
    • pkg/warnings: Integrated centralized warning collection system
      • Global warning collector for system-wide warning aggregation
      • Severity levels (INFO, LOW, MEDIUM, HIGH, CRITICAL)
      • Warning deduplication and suppression capabilities
      • Automatic cleanup of old resolved warnings
      • Recommended actions for common warning categories
    • pkg/alerting: Integrated multi-channel alerting system
      • Configurable alert evaluation with periodic rule checking
      • Support for multiple notification channels (Slack, PagerDuty, Email, Webhook)
      • Alert rules with thresholds and severity levels
      • Disabled by default pending alert rules and channel configuration
      • Enable via ALERTING_ENABLED=true
  • Contact Header Fix: SIP Contact headers now use actual configured port
    • Tracks listen addresses per transport (UDP/TCP/TLS)
    • Resolves correct host:port considering NAT configuration
    • Fixes issue where Contact showed :5060 instead of configured port
  • UDP MTU Handling: Increased UDP MTU to 4096 bytes for large SIPREC messages
    • Combined with compact XML format for maximum efficiency
    • Prevents packet fragmentation issues
  • RFC 7865 Compliance: Improved SIPREC metadata validation
    • Missing state attribute now treated as warning instead of error
    • Added "unknown" as valid recording state for RFC 7865-only implementations
    • Support for participantsessionassoc elements
    • Enhanced validation distinguishes between RFC 7865 and RFC 7866 requirements
  • Encryption Configuration: Changed ENCRYPTION_KEY_STORE default from "file" to "memory"
    • Enables out-of-box operation without file path configuration
    • Memory storage suitable for development and testing environments
    • File and vault storage remain available for production use
  • Message Size Optimization: Compact XML format prevents MTU exceeded errors
    • Changed from indented to compact XML for SIPREC metadata responses
    • Reduces message size by 12-15% to stay within UDP MTU limits
    • Fixes "size of packet larger than MTU" SIP 200 OK response failures

Fixed

  • SIP 200 OK responses failing due to MTU size exceeded on UDP transport
  • SIPREC metadata with missing state attribute incorrectly rejected as critical error
  • App startup failures when ENCRYPTION_KEY_STORE not configured
  • Broken metrics endpoint returning empty data due to uninitialized registry
  • Contact headers showing wrong port number in SIP responses

Notes

  • Remaining Unintegrated Packages: The following packages are implemented but not yet integrated:
    • pkg/clustering: Redis-based multi-instance clustering (requires Redis setup and configuration)
    • pkg/failover: Session failover system (depends on clustering infrastructure)
    • pkg/app, pkg/core, pkg/util (legacy): Utility packages with minimal value
    • These packages can be integrated when their specific features are needed
  • Recently Integrated Packages: pkg/auth, pkg/warnings, and pkg/alerting are now integrated and available for use

Added - Resource Optimization & Advanced Features

  • Advanced Resource Optimization: Comprehensive memory and CPU optimization for 1000+ concurrent sessions
  • Memory Pool Management: Intelligent buffer pooling reducing GC pressure by 50-70%
  • Worker Pool Architecture: Dynamic goroutine scaling with category-specific pools
  • Session Caching: LRU cache with TTL for frequently accessed sessions
  • Sharded Data Structures: 64-shard maps for reduced lock contention
  • Enhanced Port Management: RTP port reuse optimization with allocation statistics
  • Optimized Audio Processing: Frame-based processing with multi-channel support
  • Advanced Session Manager: High-performance session management with asynchronous operations

Added - SIPREC Protocol Enhancements

  • Complete SIPREC Metadata Handling: Full RFC 7865/7866 metadata schema support
  • Advanced Participant Management: Complex participant configurations with roles and AORs
  • Stream Configuration: Audio/video stream management with mixing support
  • Session State Transitions: Pause/resume with sequence tracking and validation
  • Comprehensive Validation: Detailed metadata validation with error reporting
  • Response Generation: RFC-compliant multipart MIME response creation
  • Session Control Operations: PauseRecording(), ResumeRecording(), and state management

Added - Codec & Media Support

  • Enhanced Codec Support: Full Opus and EVS codec implementations with decoding
  • Media Quality Metrics: ITU-T G.107 E-model for MOS score calculation
  • Adaptive Bitrate Control: Network-aware dynamic bitrate adjustment
  • Multi-Channel Audio: Stereo enhancement, channel separation, and mixing
  • Audio Processing Pipeline: Noise reduction, echo cancellation, and VAD

Added - Infrastructure & Monitoring

  • Real-time transcription streaming to AMQP message queues
  • Production-ready AMQP implementation with fault tolerance and graceful degradation
  • Comprehensive Performance Metrics: Memory, session, worker pool, and cache statistics
  • Resource Utilization Monitoring: Real-time tracking of system resources
  • Health Check APIs: Detailed health and performance monitoring endpoints
  • Enhanced Testing Suite: Resource optimization and SIPREC metadata testing

Optimized

  • Concurrent Session Handling: 64-shard session storage for reduced lock contention
  • Memory Efficiency: Object pooling and buffer reuse for zero-allocation hot paths
  • Audio Processing: Frame-based processing reducing memory pressure
  • Network Operations: Enhanced RTP port management with reuse tracking
  • Session Lookup: Sub-millisecond session access through intelligent caching

Fixed

  • Fixed potential nil pointer dereference in SDP handler when no SDP content is provided
  • Added generateDefaultSDP function to properly handle nil SDP cases
  • Updated prepareSdpResponse function to handle empty or nil SDP inputs
  • Simplified SDP generation code by consolidating to the generateSDPAdvanced function
  • Resolved import cycles in resource optimization modules

Changed

  • Refactored session management for high-concurrency optimization
  • Enhanced SIPREC parser with comprehensive metadata validation
  • Improved SDP handling code for better maintainability and robustness
  • Updated project structure to include resource optimization utilities
  • Enhanced documentation with performance optimization guide