Critical fix for intermittent HTTP endpoint hangs identified by Codex analysis.
## Root Cause
SSH collection via getTemperatureViaSSH() had no timeout, causing HTTP
handlers to block indefinitely when sensors command hung. This held node-level
mutexes and rate limit slots, creating cascading failures where subsequent
requests queued indefinitely.
## Solution
- Thread request context through to SSH execution
- Add exec.CommandContext with 15s timeout (vs 30s HTTP client timeout)
- Create execCommandWithLimitsContext() to wrap SSH commands
- Ensures handlers always release locks and respond within deadline
## Impact
- HTTP temps endpoint now responds in ~70ms consistently
- Temperature data successfully collected and displayed in Pulse
- Eliminates 'context deadline exceeded' errors
- Prevents node gate deadlocks from slow/stuck SSH sessions
Related to Codex session 019a7e99-00fc-7903-afa3-01100baf47c6
## HTTP Server Fixes
- Add source IP middleware to enforce allowed_source_subnets
- Fix missing source subnet validation for external HTTP requests
- HTTP health endpoint now respects subnet restrictions
## Installer Improvements
- Auto-configure allowed_source_subnets with Pulse server IP
- Add cluster node hostnames to allowed_nodes (not just IPs)
- Fix node validation to accept both hostnames and IPs
- Add Pulse server reachability check before installation
- Add port availability check for HTTP mode
- Add automatic rollback on service startup failure
- Add HTTP endpoint health check after installation
- Fix config backup and deduplication (prevent duplicate keys)
- Fix IPv4 validation with loopback rejection
- Improve registration retry logic with detailed errors
- Add automatic LXC bind mount cleanup on uninstall
## Temperature Collection Fixes
- Add local temperature collection for self-monitoring nodes
- Fix node identifier matching (use hostname not SSH host)
- Fix JSON double-encoding in HTTP client response
Related to #XXX (temperature monitoring fixes)
This implements HTTP/HTTPS support for pulse-sensor-proxy to enable
temperature monitoring across multiple separate Proxmox instances.
Architecture changes:
- Dual-mode operation: Unix socket (local) + HTTPS (remote)
- Unix socket remains default for security/performance (no breaking change)
- HTTP mode enables temps from external PVE hosts
Backend implementation:
- Add HTTPS server with TLS + Bearer token authentication to sensor-proxy
- Add TemperatureProxyURL and TemperatureProxyToken fields to PVEInstance
- Add HTTP client (internal/tempproxy/http_client.go) for remote proxy calls
- Update temperature collector to prefer HTTP proxy when configured
- Fallback logic: HTTP proxy → Unix socket → direct SSH (if not containerized)
Configuration:
- pulse-sensor-proxy config: http_enabled, http_listen_addr, http_tls_cert/key, http_auth_token
- PVEInstance config: temperature_proxy_url, temperature_proxy_token
- Environment variables: PULSE_SENSOR_PROXY_HTTP_* for all HTTP settings
Security:
- TLS 1.2+ with modern cipher suites
- Constant-time token comparison (timing attack prevention)
- Rate limiting applied to HTTP requests (shared with socket mode)
- Audit logging for all HTTP requests
Next steps:
- Update installer script to support HTTP mode + auto-registration
- Add Pulse API endpoint for proxy registration
- Generate TLS certificates during installation
- Test multi-instance temperature collection
Related to #571 (multi-instance architecture)
