main.go

// Package main implements a GitHub Copilot API proxy that exposes both
// OpenAI-compatible and Anthropic-compatible endpoints.
package main

import (
	"context"
	"fmt"
	"log"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"
)

const (
	defaultAddr = "127.0.0.1:8080"
	logPrefix   = "[proxy] "
)

var logger = log.New(os.Stdout, logPrefix, log.LstdFlags)

func main() {
	addr := os.Getenv("PROXY_ADDR")
	if addr == "" {
		addr = defaultAddr
	}

	// Initialize token manager.
	tm, err := NewTokenManager()
	if err != nil {
		logger.Fatalf("failed to create token manager: %v", err)
	}

	// Initialize usage tracker.
	dbPath := os.Getenv("USAGE_DB_PATH")
	if dbPath == "" {
		dbPath = "usage.db"
	}
	tracker, err := NewUsageTracker(dbPath)
	if err != nil {
		logger.Fatalf("failed to create usage tracker: %v", err)
	}
	defer tracker.Close()

	// Build router.
	mux := http.NewServeMux()
	mux.HandleFunc("/health", handleHealth)
	mux.HandleFunc("/usage", tracker.HandleUsage)
	mux.HandleFunc("/v1/chat/completions", makeOpenAIHandler(tm, tracker))
	mux.HandleFunc("/v1/messages", makeAnthropicHandler(tm, tracker))

	srv := &http.Server{
		Addr:         addr,
		Handler:      mux,
		ReadTimeout:  120 * time.Second,
		WriteTimeout: 120 * time.Second,
		IdleTimeout:  60 * time.Second,
	}

	// Graceful shutdown on signal.
	quit := make(chan os.Signal, 1)
	signal.Notify(quit, os.Interrupt, syscall.SIGTERM)

	go func() {
		logger.Printf("listening on http://%s", addr)
		if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			logger.Fatalf("server error: %v", err)
		}
	}()

	<-quit
	logger.Println("shutting down…")
	ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
	defer cancel()
	if err := srv.Shutdown(ctx); err != nil {
		logger.Printf("shutdown error: %v", err)
	}
	logger.Println("stopped")
}

func handleHealth(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	fmt.Fprintln(w, `{"status":"ok"}`)
}