rcourtman 1e25fa572a security: add resilience and error handling to tempproxy client ...

Implements comprehensive client-side improvements for production reliability:

1. Context Support with Deadlines:
   - Added callWithContext() for context-aware RPC calls
   - Respects context deadlines and cancellation
   - Prevents goroutine pileup under network issues

2. Exponential Backoff with Jitter:
   - Automatic retry with exponential backoff (100ms → 10s)
   - ±10% jitter to prevent thundering herd
   - Max 3 retries for transient failures
   - Smart retry decision based on error classification

3. Error Classification:
   - ProxyError type with classification (Transport, Auth, SSH, Sensor, Timeout)
   - Retryable vs non-retryable error identification
   - Better error messages for debugging
   - Structured error handling throughout

4. Improved Connection Handling:
   - DialContext for cancellable connections
   - Proper deadline propagation
   - Clean separation of single-attempt vs retry logic
   - Legacy call() method preserved for backwards compatibility

Security Notes:
- SSH fallback already blocked in containers (temperature.go:69-77)
- Per-client token auth not needed after method-level authz (commit d55112ac4)
- ID-mapped root blocked from privileged methods

Performance:
- No retry on non-retryable errors (auth, sensor failures)
- Context cancellation short-circuits retry loops
- Jitter prevents synchronized retry storms

Addresses Codex findings #4 and #5 from security audit.

2025-10-19 16:37:11 +00:00

..

client.go

security: add resilience and error handling to tempproxy client

2025-10-19 16:37:11 +00:00