1 files changed, 165 insertions, 0 deletions
diff --git a/cmd/goget/main.go b/cmd/goget/main.go
new file mode 100644
index 0000000..ae8b3a6
--- /dev/null
+++ b/cmd/goget/main.go
@@ -0,0 +1,165 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"net/http"
+	"net/url"
+	"os"
+	"os/signal"
+	"slices"
+	"strings"
+	"syscall"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+	"golang.org/x/mod/semver"
+)
+
+const (
+	forgeDomain = "code.fcuny.net"
+	forgeUser   = "fcuny"
+	goPkgDomain = "go.fcuny.net"
+)
+
+var (
+	goGetReqs = promauto.NewCounterVec(prometheus.CounterOpts{
+		Name: "goget_requests_total",
+		Help: "go get requests processed, by repository name.",
+	}, []string{"name"})
+
+	modules = []string{"x"}
+)
+
+func main() {
+	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
+	defer cancel()
+
+	metricsMux := http.NewServeMux()
+	metricsMux.Handle("/metrics", promhttp.Handler())
+	metricsServer := &http.Server{
+		Addr: ":9091", Handler: metricsMux,
+		ReadTimeout: 10 * time.Second, WriteTimeout: 10 * time.Second,
+	}
+
+	go func() {
+		log.Println("Starting metrics server on :9091")
+		if err := metricsServer.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+			log.Printf("Metrics server error: %v", err)
+		}
+	}()
+
+	s := &http.Server{
+		Addr:         ":8080",
+		Handler:      handler(),
+		ReadTimeout:  10 * time.Second,
+		WriteTimeout: 10 * time.Second,
+		IdleTimeout:  1 * time.Minute,
+	}
+
+	go func() {
+		log.Println("Starting main server on :8080")
+		if err := s.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+			log.Printf("Main server error: %v", err)
+		}
+	}()
+
+	<-ctx.Done()
+	log.Println("Shutdown signal received, starting graceful shutdown...")
+
+	shutdownCtx, shutdownCancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer shutdownCancel()
+
+	var shutdownErr error
+
+	log.Println("Shutting down main server...")
+	if err := s.Shutdown(shutdownCtx); err != nil {
+		log.Printf("Main server shutdown error: %v", err)
+		shutdownErr = err
+	}
+
+	log.Println("Shutting down metrics server...")
+	if err := metricsServer.Shutdown(shutdownCtx); err != nil {
+		log.Printf("Metrics server shutdown error: %v", err)
+		if shutdownErr == nil {
+			shutdownErr = err
+		}
+	}
+
+	if shutdownErr != nil {
+		log.Printf("Shutdown completed with errors")
+		os.Exit(1)
+	}
+
+	log.Println("Shutdown completed successfully")
+}
+
+func handler() http.Handler {
+	mux := http.NewServeMux()
+
+	mux.Handle(goPkgDomain+"/{name}", siteHandler(modules))
+	mux.Handle(goPkgDomain+"/{name}/", siteHandler(modules))
+
+	goGetMux := http.NewServeMux()
+	for _, name := range modules {
+		module := goPkgDomain + "/" + name
+		goGetMux.Handle(
+			module+"/",
+			goImportHandler(module, "https://"+forgeDomain+"/"+forgeUser+"/"+name),
+		)
+	}
+
+	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodGet {
+			status := http.StatusMethodNotAllowed
+			http.Error(rw, http.StatusText(status), status)
+			return
+		}
+
+		if r.URL.Query().Get("go-get") == "1" {
+			goGetMux.ServeHTTP(rw, r)
+			return
+		}
+		mux.ServeHTTP(rw, r)
+	})
+}
+
+func goImportHandler(module, repo string) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		goGetReqs.WithLabelValues(module).Inc()
+		w.Header().Set("Content-Type", "text/html; charset=UTF-8")
+		if _, err := fmt.Fprintf(w, `<head><meta name="go-import" content="%s git %s">`, module, repo); err != nil {
+			log.Printf("Error writing response: %v", err)
+		}
+	})
+}
+
+func siteHandler(names []string) http.Handler {
+	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+		name := r.PathValue("name")
+		name, version, hasV := strings.Cut(name, "@")
+		if !hasV {
+			name, _, _ = strings.Cut(name, ".")
+		}
+		if hasV && !semver.IsValid(version) || !slices.Contains(names, name) {
+			http.NotFound(rw, r)
+			return
+		}
+		u := &url.URL{
+			Scheme: "https",
+			Host:   forgeDomain,
+			Path:   forgeUser + r.URL.Path,
+		}
+		if !hasV {
+			path, symbol, hasSymbol := strings.Cut(r.URL.Path, ".")
+			if hasSymbol {
+				u.Path = forgeUser + "/" + path
+				u.Fragment = symbol
+			}
+		}
+		http.Redirect(rw, r, u.String(), http.StatusFound)
+	})
+}