Remove Prometheus metrics integration from proxy and circuit breaker

Eliminate Prometheus client dependencies and related metric registration
from proxy and circuit breaker code. Update documentation to reflect
removal of worker pool metrics and production monitoring. This simplifies
the codebase and reduces external dependencies.

Author: jxu3

README.md

@@ -84,9 +84,8 @@ This service includes enterprise-grade performance optimizations:
 
 ### 📊 Monitoring & Observability
 - **Profiling Endpoints**: `/debug/pprof/*` for memory, CPU, and goroutine analysis
-- **Enhanced Logging**: Circuit breaker state, request coalescing, worker pool metrics, and performance data
+- **Enhanced Logging**: Circuit breaker state, request coalescing, and performance data
 - **Health Monitoring**: Detailed `/health` endpoint for load balancer integration
-- **Production Metrics**: Built-in support for operational monitoring and worker pool status
 
 ## Quickstart with Makefile
 
@@ -467,42 +466,6 @@ print(response)
 
 ## Development
 
-### Project Structure
-```
-github-copilot-svcs/
-├── cmd/
-│   └── github-copilot-svcs/
-│       └── main.go            # Main application entry point
-├── internal/                  # Private application code
-│   ├── auth/
-│   │   └── auth.go           # GitHub Copilot authentication
-│   ├── cli/
-│   │   └── cli.go            # CLI command handling
-│   ├── config/
-│   │   └── config.go         # Configuration management
-│   ├── logger/
-│   │   └── logger.go         # Structured logging
-│   ├── models/
-│   │   └── models.go         # Model management and mapping
-│   ├── proxy/
-│   │   └── proxy.go          # Reverse proxy implementation
-│   └── server/
-│       └── server.go         # HTTP server and graceful shutdown
-├── pkg/                      # Public API packages
-│   └── transform/
-│       └── transform.go      # Request/response transformation
-├── test/                     # Test files organized by type
-│   ├── integration/          # Integration tests
-│   ├── unit/                 # Unit tests
-│   └── testutils/            # Test utilities
-├── config.example.json       # Example configuration
-├── docker-compose.yml        # Docker Compose setup
-├── Dockerfile               # Docker image definition
-├── Makefile                 # Build and development tasks
-├── go.mod                   # Go module definition
-└── README.md                # This documentation
-```
-
 ### Building from Source
 ```bash
 git clone <repository>

cmd/github-copilot-svcs/main.go

@@ -12,7 +12,6 @@ var version = "dev"
 func main() {
 	// Initialize logger early
 	internal.Init()
-	internal.RegisterProxyMetrics()
 
 	const minArgsRequired = 2
 	if len(os.Args) < minArgsRequired {

go.mod

@@ -8,10 +8,6 @@ require (
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
-	github.com/prometheus/client_golang v1.23.0 // indirect
-	github.com/prometheus/client_model v0.6.2 // indirect
-	github.com/prometheus/common v0.65.0 // indirect
-	github.com/prometheus/procfs v0.16.1 // indirect
 	golang.org/x/sys v0.33.0 // indirect
 	google.golang.org/protobuf v1.36.6 // indirect
 )

go.sum

@@ -4,14 +4,6 @@ github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UF
 github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq1c1nUAm88MOHcQC9l5mIlSMApZMrHA=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
-github.com/prometheus/client_golang v1.23.0 h1:ust4zpdl9r4trLY/gSjlm07PuiBq2ynaXXlptpfy8Uc=
-github.com/prometheus/client_golang v1.23.0/go.mod h1:i/o0R9ByOnHX0McrTMTyhYvKE4haaf2mW08I+jGAjEE=
-github.com/prometheus/client_model v0.6.2 h1:oBsgwpGs7iVziMvrGhE53c/GrLUsZdHnqNwqPLxwZyk=
-github.com/prometheus/client_model v0.6.2/go.mod h1:y3m2F6Gdpfy6Ut/GBsUqTWZqCUvMVzSfMLjcu6wAwpE=
-github.com/prometheus/common v0.65.0 h1:QDwzd+G1twt//Kwj/Ww6E9FQq1iVMmODnILtW1t2VzE=
-github.com/prometheus/common v0.65.0/go.mod h1:0gZns+BLRQ3V6NdaerOhMbwwRbNh9hkGINtQAsP5GS8=
-github.com/prometheus/procfs v0.16.1 h1:hZ15bTNuirocR6u0JZ6BAHHmwS1p8B4P6MRqxtzMyRg=
-github.com/prometheus/procfs v0.16.1/go.mod h1:teAbpZRB1iIAJYREa1LsoWUXykVXA1KlTmWl8x/U+Is=
 golang.org/x/sys v0.33.0 h1:q3i8TbbEz+JRD9ywIRlyRAQbM0qF7hu24q3teo2hbuw=
 golang.org/x/sys v0.33.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
 google.golang.org/protobuf v1.36.6 h1:z1NpPI8ku2WgiWnf+t9wTPsn6eP1L7ksHUlkfLvd9xY=

internal/proxy.go

@@ -11,8 +11,6 @@ import (
 	"strings"
 	"sync"
 	"time"
-
-	"github.com/prometheus/client_golang/prometheus"
 )
 
 const (
@@ -42,42 +40,6 @@ const (
 	ProxyCBStateHalfOpen = 2
 )
 
-// Prometheus metrics for proxy and circuit breaker
-var (
-	proxyRequestsTotal = prometheus.NewCounter(
-		prometheus.CounterOpts{
-			Name: "proxy_requests_total",
-			Help: "Total number of proxy requests",
-		},
-	)
-	proxyRetriesTotal = prometheus.NewCounter(
-		prometheus.CounterOpts{
-			Name: "proxy_retries_total",
-			Help: "Total number of proxy request retries",
-		},
-	)
-	proxyFailuresTotal = prometheus.NewCounterVec(
-		prometheus.CounterOpts{
-			Name: "proxy_failures_total",
-			Help: "Total number of proxy failures, labeled by reason",
-		},
-		[]string{"reason"},
-	)
-	proxyCircuitBreakerState = prometheus.NewGauge(
-		prometheus.GaugeOpts{
-			Name: "proxy_circuit_breaker_state",
-			Help: "Proxy circuit breaker state: 0=closed, 1=open, 2=half-open",
-		},
-	)
-)
-
-func RegisterProxyMetrics() {
-	prometheus.MustRegister(proxyRequestsTotal)
-	prometheus.MustRegister(proxyRetriesTotal)
-	prometheus.MustRegister(proxyFailuresTotal)
-	prometheus.MustRegister(proxyCircuitBreakerState)
-}
-
 // CircuitBreakerState represents the state of the circuit breaker
 type CircuitBreakerState int
 
@@ -272,15 +234,7 @@ func (cb *CircuitBreaker) canExecute() bool {
 	cb.mutex.RLock()
 	defer cb.mutex.RUnlock()
 
-	// Set gauge for current state
-	switch cb.state {
-	case CircuitClosed:
-		proxyCircuitBreakerState.Set(ProxyCBStateClosed)
-	case CircuitOpen:
-		proxyCircuitBreakerState.Set(ProxyCBStateOpen)
-	case CircuitHalfOpen:
-		proxyCircuitBreakerState.Set(ProxyCBStateHalfOpen)
-	}
+	// No metrics to update for circuit breaker state changes
 
 	if cb.state == CircuitClosed {
 		return true
@@ -291,7 +245,6 @@ func (cb *CircuitBreaker) canExecute() bool {
 			cb.mutex.RUnlock()
 			cb.mutex.Lock()
 			cb.state = CircuitHalfOpen
-			proxyCircuitBreakerState.Set(ProxyCBStateHalfOpen)
 			cb.mutex.Unlock()
 			cb.mutex.RLock()
 			return true
@@ -309,7 +262,6 @@ func (cb *CircuitBreaker) onSuccess() {
 
 	cb.failureCount = 0
 	cb.state = CircuitClosed
-	proxyCircuitBreakerState.Set(ProxyCBStateClosed)
 }
 
 func (cb *CircuitBreaker) onFailure() {
@@ -321,7 +273,6 @@ func (cb *CircuitBreaker) onFailure() {
 
 	if cb.failureCount >= circuitBreakerFailureThreshold {
 		cb.state = CircuitOpen
-		proxyCircuitBreakerState.Set(ProxyCBStateOpen)
 	}
 }
 
@@ -457,14 +408,10 @@ func (s *ProxyService) makeRequestWithRetry(req *http.Request, body []byte) (*ht
 	var lastResp *http.Response
 	var lastErr error
 
-	// Increment total proxy request metric
-	proxyRequestsTotal.Inc()
-
 	for attempt := 1; attempt <= maxChatRetries; attempt++ {
 		// Create a new request for each attempt with the original context
 		retryReq, err := http.NewRequestWithContext(req.Context(), req.Method, req.URL.String(), bytes.NewBuffer(body))
 		if err != nil {
-			proxyFailuresTotal.WithLabelValues("request_creation").Inc()
 			return nil, err
 		}
 
@@ -479,16 +426,12 @@ func (s *ProxyService) makeRequestWithRetry(req *http.Request, body []byte) (*ht
 
 		resp, err := s.httpClient.Do(retryReq)
 		if err != nil {
-			proxyFailuresTotal.WithLabelValues("network_error").Inc()
 			lastErr = err
 			if attempt == maxChatRetries {
 				Error("Request failed after max attempts", "attempts", maxChatRetries, "error", err)
 				return nil, err
 			}
 
-			// Increment retry metric
-			proxyRetriesTotal.Inc()
-
 			// Context-aware waiting instead of blocking sleep
 			waitTime := time.Duration(baseChatRetryDelay*attempt*attempt) * time.Second
 			Warn("Request failed, retrying", "attempt", attempt, "wait_time", waitTime, "error", err)
@@ -512,12 +455,6 @@ func (s *ProxyService) makeRequestWithRetry(req *http.Request, body []byte) (*ht
 			return resp, nil
 		}
 
-		// Increment retry metric for retriable status codes
-		proxyRetriesTotal.Inc()
-
-		// Increment failure metric for retriable status codes
-		proxyFailuresTotal.WithLabelValues(fmt.Sprintf("http_%d", resp.StatusCode)).Inc()
-
 		// Close the response body before retrying
 		if closeErr := resp.Body.Close(); closeErr != nil {
 			Warn("Failed to close response body during retry", "error", closeErr)

internal/server.go

@@ -11,8 +11,6 @@ import (
 	"sync"
 	"syscall"
 	"time"
-
-	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
 // Constants for timeout values
@@ -120,7 +118,6 @@ func NewServer(cfg *Config, httpClient *http.Client) *Server {
 	mux.HandleFunc("/v1/models", modelsService.Handler())
 	mux.HandleFunc("/v1/chat/completions", proxyService.Handler())
 	mux.HandleFunc("/health", healthChecker.Handler())
-	mux.Handle("/metrics", promhttp.Handler())
 
 	// Add pprof endpoints for profiling
 	mux.HandleFunc("/debug/pprof/", http.DefaultServeMux.ServeHTTP)