fix docker

healthcheck/healthcheck.go

@@ -0,0 +1,61 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"time"
+)
+
+const (
+	defaultPort    = "3000"
+	requestTimeout = 5 * time.Second
+)
+
+func main() {
+	ctx, cancel := context.WithTimeout(context.Background(), requestTimeout)
+	defer cancel()
+
+	if err := run(ctx); err != nil {
+		_, _ = fmt.Fprintf(os.Stderr, "health check failed: %v\n", err)
+		os.Exit(1)
+	}
+
+	os.Exit(0)
+}
+
+func run(ctx context.Context) error {
+	port := os.Getenv("SERVER_PORT")
+	if port == "" {
+		port = defaultPort
+	}
+
+	url := fmt.Sprintf("http://localhost:%s/health", port)
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
+	if err != nil {
+		return fmt.Errorf("could not create request: %w", err)
+	}
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return fmt.Errorf("request to %s failed: %w", url, err)
+	}
+	defer func() {
+		if closeErr := resp.Body.Close(); closeErr != nil {
+			_, _ = fmt.Fprintf(os.Stderr, "warning: failed to close response body: %v\n", closeErr)
+		}
+	}()
+
+	if _, err := io.Copy(io.Discard, resp.Body); err != nil {
+		return fmt.Errorf("failed to discard response body: %w", err)
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("received non-200 status code: %d", resp.StatusCode)
+	}
+
+	return nil
+}