Fix healthchecks

Dockerfile

@@ -29,13 +29,16 @@ COPY web/robots.txt ./web/robots.txt
 
 RUN go build -trimpath -mod=readonly -buildvcs=false -ldflags="-s -w" \
     -o /out/secret-api ./cmd/server
+RUN go build -trimpath -mod=readonly -buildvcs=false -ldflags="-s -w" \
+    -o /out/healthcheck ./cmd/healthcheck
 
 # runtime
 FROM gcr.io/distroless/base:nonroot@sha256:746b9dbe3065a124395d4a7698241dbd6f3febbf01b73e48f942aabd7b8e5eac
 
 WORKDIR /app
 
 COPY --from=builder --chown=nonroot:nonroot /out/secret-api /app/secret-api
+COPY --from=builder --chown=nonroot:nonroot /out/healthcheck /app/healthcheck
 COPY --from=builder --chown=nonroot:nonroot /src/web/static /app/web/static
 COPY --from=builder --chown=nonroot:nonroot /src/web/robots.txt /app/web/robots.txt
 

cmd/healthcheck/main.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+	"time"
+)
+
+func check(port string) error {
+	url := fmt.Sprintf("http://localhost:%s/health", port)
+
+	client := &http.Client{Timeout: 3 * time.Second}
+	resp, err := client.Get(url)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf(
+			"unexpected status code: %d", resp.StatusCode,
+		)
+	}
+	return nil
+}
+
+func main() {
+	port := os.Getenv("PORT")
+	if port == "" {
+		port = "8080"
+	}
+
+	if err := check(port); err != nil {
+		os.Exit(1)
+	}
+}

cmd/healthcheck/main_test.go

@@ -0,0 +1,54 @@
+package main
+
+import (
+	"net"
+	"net/http"
+	"testing"
+)
+
+func testServer(
+	t *testing.T, status int,
+) string {
+	t.Helper()
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("/health", func(
+		w http.ResponseWriter, r *http.Request,
+	) {
+		w.WriteHeader(status)
+	})
+
+	ln, err := net.Listen("tcp", "localhost:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	srv := &http.Server{Handler: mux}
+	go func() { _ = srv.Serve(ln) }()
+	t.Cleanup(func() { srv.Close() })
+
+	_, port, _ := net.SplitHostPort(ln.Addr().String())
+	return port
+}
+
+func TestCheck(t *testing.T) {
+	t.Run("returns nil when server is healthy", func(t *testing.T) {
+		port := testServer(t, http.StatusOK)
+		if err := check(port); err != nil {
+			t.Fatalf("expected healthy, got error: %v", err)
+		}
+	})
+
+	t.Run("returns error on unhealthy status", func(t *testing.T) {
+		port := testServer(t, http.StatusServiceUnavailable)
+		if err := check(port); err == nil {
+			t.Fatal("expected error for unhealthy status")
+		}
+	})
+
+	t.Run("returns error when no server is running", func(t *testing.T) {
+		if err := check("0"); err == nil {
+			t.Fatal("expected error when no server running")
+		}
+	})
+}

docker-compose.yml

@@ -15,7 +15,7 @@ services:
     ports:
       - "8080:8080"
     healthcheck:
-      test: ["CMD", "wget", "--spider", "http://localhost:8080/health/"]
+      test: ["CMD", "/app/healthcheck"]
       interval: 30s
       timeout: 5s
       retries: 3

web/frontend/App.css

@@ -15,7 +15,7 @@
   color-scheme: light;
 }
 
-[data-theme="dark"] {
+[data-theme='dark'] {
   --primary-color: #e8e8e8;
   --secondary-color: #111;
   --background-color: #111;

web/frontend/components/Layout/index.tsx

@@ -10,11 +10,21 @@ export function Layout({ children, onToggleTheme }: LayoutProps) {
   return (
     <div class={styles.container}>
       <div class={styles.nav}>
-        <a href="/" class={styles.navLink}>create</a>
-        <a href="/about" class={styles.navLink}>about</a>
+        <a href="/" class={styles.navLink}>
+          create
+        </a>
+        <a href="/about" class={styles.navLink}>
+          about
+        </a>
         <span>{`secretapi \u00A9 ${new Date().getFullYear()}`}</span>
         <button class={styles.themeToggle} onClick={onToggleTheme} aria-label="Toggle theme">
-          <svg width="14" height="14" viewBox="0 0 14 14" fill="none" xmlns="http://www.w3.org/2000/svg">
+          <svg
+            width="14"
+            height="14"
+            viewBox="0 0 14 14"
+            fill="none"
+            xmlns="http://www.w3.org/2000/svg"
+          >
             <circle cx="7" cy="7" r="6" stroke="currentColor" stroke-width="1.5" />
             <path d="M7 1 A6 6 0 0 0 7 13 Z" fill="currentColor" />
           </svg>