chore: bump version to 2.3.1 and update documentation

Updated version across all files and documentation for v2.3.1 release:
- api.py: Updated FastAPI version and health endpoint version
- tests/test_api_integration.py: Updated version assertion
- README.md: Updated version badge and title
- CHANGELOG.md: Added comprehensive v2.3.1 release notes

Changes include:
- Detailed documentation of the race condition fix
- Explanation of the problem, root cause, and solution
- Testing verification notes
- Use cases where the bug could occur

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: gmathy2104

CHANGELOG.md

@@ -5,6 +5,26 @@ All notable changes to Pi Camera Service will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [2.3.1] - 2025-11-22
+
+### Fixed
+
+#### Critical Race Condition in Camera Reconfiguration
+- **CRITICAL BUG FIX**: Added global lock to prevent race conditions in concurrent camera reconfiguration
+  - **Problem**: Multiple simultaneous requests to change resolution or framerate could cause:
+    - Service crashes with "Failed to set framerate" errors
+    - Internal server errors and deadlocks
+    - Streaming interruptions and inconsistent camera state
+  - **Root cause**: While `StreamingManager` and `CameraController` had internal locks, there was no global lock protecting the complete stop→reconfigure→start sequence at the API level
+  - **Solution**: Added `_reconfiguration_lock` (RLock) in `api.py` to serialize all reconfiguration operations
+  - **Impact**: Concurrent requests to `/v1/camera/resolution` and `/v1/camera/framerate` now execute sequentially and safely
+  - **Testing**: Verified with multiple concurrent requests - all now succeed without errors or crashes
+
+This was an intermittent, timing-dependent bug that could occur when:
+- UI sends multiple rapid configuration changes
+- Automation scripts make concurrent API calls
+- Multiple clients access the API simultaneously
+
 ## [2.3.0] - 2025-11-22
 
 ### Added

README.md

@@ -2,9 +2,9 @@
 
 Production-ready **FastAPI** microservice for controlling Raspberry Pi Camera (libcamera/Picamera2) with **H.264 streaming** to **MediaMTX** via RTSP.
 
-**Version 2.3** - Dynamic framerate control with intelligent clamping and comprehensive camera capabilities!
+**Version 2.3.1** - Critical race condition fix + Dynamic framerate control with intelligent clamping!
 
-[![Version](https://img.shields.io/badge/version-2.3.0-blue.svg)](https://github.com/gmathy2104/pi-camera-service/releases)
+[![Version](https://img.shields.io/badge/version-2.3.1-blue.svg)](https://github.com/gmathy2104/pi-camera-service/releases)
 [![Python](https://img.shields.io/badge/python-3.9+-green.svg)](https://www.python.org/)
 [![FastAPI](https://img.shields.io/badge/FastAPI-0.121+-teal.svg)](https://fastapi.tiangolo.com/)
 [![License](https://img.shields.io/badge/license-MIT-orange.svg)](LICENSE)
@@ -381,7 +381,7 @@ sudo journalctl -u pi-camera-service -f
   "status": "healthy",
   "camera_configured": true,
   "streaming_active": true,
-  "version": "2.3.0"
+  "version": "2.3.1"
 }
 ```
 

camera_service/api.py

@@ -168,7 +168,7 @@ async def lifespan(app: FastAPI) -> AsyncGenerator[None, None]:
 app = FastAPI(
     title="Pi Camera Service",
     description="API for controlling Raspberry Pi camera and streaming to MediaMTX via RTSP",
-    version="2.3.0",
+    version="2.3.1",
     lifespan=lifespan,
 )
 
@@ -478,7 +478,7 @@ def health_check() -> HealthResponse:
         status="healthy" if camera_controller is not None else "initializing",
         camera_configured=camera_controller._configured if camera_controller else False,
         streaming_active=streaming_manager.is_streaming() if streaming_manager else False,
-        version="2.3.0",
+        version="2.3.1",
     )
 
 

tests/test_api_integration.py

@@ -62,7 +62,7 @@ def test_health_endpoint(self) -> None:
         assert data["status"] == "healthy"
         assert "camera_configured" in data
         assert "streaming_active" in data
-        assert data["version"] == "2.3.0"
+        assert data["version"] == "2.3.1"
 
         print("✓ Health endpoint working")