Feature 01 task 1: Go module, fail-fast config and /health (#2)

Co-authored-by: dev_agent <dev_agent@cubecraftlabs.com>
Co-committed-by: dev_agent <dev_agent@cubecraftlabs.com>

cmd/server/main.go

@@ -0,0 +1,80 @@
+// Command server runs the MealQuest HTTP service.
+package main
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"log/slog"
+	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/config"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/server"
+)
+
+// version is set at build time with -ldflags "-X main.version=<version>".
+var version = "dev"
+
+func main() {
+	cfg, err := config.Load()
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+
+	logger := slog.New(slog.NewJSONHandler(os.Stdout, nil))
+	if err := run(cfg, logger); err != nil {
+		logger.Error("server stopped", "error", err)
+		os.Exit(1)
+	}
+}
+
+func run(cfg config.Config, logger *slog.Logger) error {
+	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
+	defer stop()
+
+	srv := &http.Server{
+		Addr:              cfg.HTTPAddr,
+		Handler:           server.NewRouter(logger, version),
+		ReadHeaderTimeout: 10 * time.Second,
+		ErrorLog:          slog.NewLogLogger(logger.Handler(), slog.LevelError),
+	}
+
+	errc := make(chan error, 1)
+	go func() {
+		logListening(logger, cfg)
+		errc <- srv.ListenAndServe()
+	}()
+
+	select {
+	case err := <-errc:
+		return err
+	case <-ctx.Done():
+	}
+
+	logger.Info("shutting down", "timeout", cfg.ShutdownTimeout.String())
+	shutdownCtx, cancel := context.WithTimeout(context.Background(), cfg.ShutdownTimeout)
+	defer cancel()
+	if err := srv.Shutdown(shutdownCtx); err != nil {
+		return fmt.Errorf("shutdown: %w", err)
+	}
+	if err := <-errc; !errors.Is(err, http.ErrServerClosed) {
+		return err
+	}
+	return nil
+}
+
+// logListening logs the startup line. Only the public URL's origin is logged
+// so no credential-bearing URL component can reach the log.
+func logListening(logger *slog.Logger, cfg config.Config) {
+	logger.Info("listening",
+		"addr", cfg.HTTPAddr,
+		"public_origin", cfg.PublicOrigin(),
+		"data_dir", cfg.DataDir,
+		"version", version,
+	)
+}

cmd/server/main_test.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	"bytes"
+	"log/slog"
+	"net/url"
+	"strings"
+	"testing"
+
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/config"
+)
+
+func TestLogListeningOmitsURLCredentials(t *testing.T) {
+	t.Parallel()
+
+	// Load rejects such URLs; this proves the log stays safe even if one
+	// reached the Config some other way.
+	u, err := url.Parse("https://alice:hunter2@meals.example.com/app?token=t0ken")
+	if err != nil {
+		t.Fatal(err)
+	}
+	var buf bytes.Buffer
+	logListening(slog.New(slog.NewJSONHandler(&buf, nil)), config.Config{HTTPAddr: ":8080", PublicURL: u})
+
+	out := buf.String()
+	for _, leak := range []string{"alice", "hunter2", "t0ken"} {
+		if strings.Contains(out, leak) {
+			t.Errorf("startup log leaks %q: %s", leak, out)
+		}
+	}
+	if !strings.Contains(out, `"public_origin":"https://meals.example.com"`) {
+		t.Errorf("startup log missing public origin: %s", out)
+	}
+}