feat(health): enhance health check to report database connection status

internal/api/handlers/v0/health.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 
 	"github.com/modelcontextprotocol/registry/internal/config"
+	"github.com/modelcontextprotocol/registry/internal/service"
 )
 
 type HealthResponse struct {
@@ -14,11 +15,18 @@ type HealthResponse struct {
 }
 
 // HealthHandler returns a handler for health check endpoint
-func HealthHandler(cfg *config.Config) http.HandlerFunc {
+func HealthHandler(cfg *config.Config, registry service.RegistryService) http.HandlerFunc {
 	return func(w http.ResponseWriter, _ *http.Request) {
+		status := "ok"
+		// Try a lightweight DB operation
+		_, _, err := registry.List("", 1)
+		if err != nil {
+			status = "db_error"
+			w.WriteHeader(http.StatusServiceUnavailable)
+		}
 		w.Header().Set("Content-Type", "application/json")
 		if err := json.NewEncoder(w).Encode(HealthResponse{
-			Status:         "ok",
+			Status:         status,
 			GitHubClientID: cfg.GithubClientID,
 		}); err != nil {
 			http.Error(w, "Failed to encode response", http.StatusInternalServerError)

internal/api/handlers/v0/health_test.go

@@ -9,14 +9,36 @@
 
 	v0 "github.com/modelcontextprotocol/registry/internal/api/handlers/v0"
 	"github.com/modelcontextprotocol/registry/internal/config"
+	"github.com/modelcontextprotocol/registry/internal/model"
 	"github.com/stretchr/testify/assert"
 )
 
+// fakeDBRegistryService is a test double for service.RegistryService
+type fakeDBRegistryService struct {
+	listErr error
+}
+
+func (f *fakeDBRegistryService) List(cursor string, limit int) ([]model.Server, string, error) {
+	return nil, "", f.listErr
+}
+
+// Implement other methods as no-ops or return zero values if needed for the interface
+func (f *fakeDBRegistryService) GetByID(id string) (*model.ServerDetail, error) {
+	return nil, nil
+}
+func (f *fakeDBRegistryService) Publish(serverDetail *model.ServerDetail) error {
+	return nil
+}
+func (f *fakeDBRegistryService) Close() error {
+	return nil
+}
+
 func TestHealthHandler(t *testing.T) {
 	// Test cases
 	testCases := []struct {
 		name           string
 		config         *config.Config
+		registry       *fakeDBRegistryService
 		expectedStatus int
 		expectedBody   v0.HealthResponse
 	}{
@@ -25,6 +47,9 @@
 			config: &config.Config{
 				GithubClientID: "test-github-client-id",
 			},
+			registry: &fakeDBRegistryService{
+				listErr: nil,
+			},
 			expectedStatus: http.StatusOK,
 			expectedBody: v0.HealthResponse{
 				Status:         "ok",
@@ -36,18 +61,35 @@
 			config: &config.Config{
 				GithubClientID: "",
 			},
+			registry: &fakeDBRegistryService{
+				listErr: nil,
+			},
 			expectedStatus: http.StatusOK,
 			expectedBody: v0.HealthResponse{
 				Status:         "ok",
 				GitHubClientID: "",
 			},
 		},
+		{
+			name: "unhealthy database",
+			config: &config.Config{
+				GithubClientID: "test-github-client-id",
+			},
+			registry: &fakeDBRegistryService{
+				listErr: assert.AnError,
+			},
+			expectedStatus: http.StatusServiceUnavailable,
+			expectedBody: v0.HealthResponse{
+				Status:         "db_error",
+				GitHubClientID: "test-github-client-id",
+			},
+		},
 	}
 
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
 			// Create handler with the test config
-			handler := v0.HealthHandler(tc.config)
+			handler := v0.HealthHandler(tc.config, tc.registry)
 
 			// Create request
 			req, err := http.NewRequestWithContext(context.Background(), http.MethodGet, "/health", nil)
@@ -84,8 +126,10 @@
 	cfg := &config.Config{
 		GithubClientID: "integration-test-client-id",
 	}
+	// Use a healthy fake registry service for integration
+	registry := &fakeDBRegistryService{listErr: nil}
 
-	server := httptest.NewServer(v0.HealthHandler(cfg))
+	server := httptest.NewServer(v0.HealthHandler(cfg, registry))
 	defer server.Close()
 
 	// Send request to the test server

internal/api/router/v0.go

@@ -15,7 +15,7 @@ func RegisterV0Routes(
 	mux *http.ServeMux, cfg *config.Config, registry service.RegistryService, authService auth.Service,
 ) {
 	// Register v0 endpoints
-	mux.HandleFunc("/v0/health", v0.HealthHandler(cfg))
+	mux.HandleFunc("/v0/health", v0.HealthHandler(cfg, registry))
 	mux.HandleFunc("/v0/servers", v0.ServersHandler(registry))
 	mux.HandleFunc("/v0/servers/{id}", v0.ServersDetailHandler(registry))
 	mux.HandleFunc("/v0/ping", v0.PingHandler(cfg))

internal/docs/swagger.yaml

@@ -36,6 +36,19 @@ paths:
                   github_client_id:
                       type: string
                       example: "your_github_client_id"
+        '503':
+          description: Database connection is unhealthy
+          content:
+            application/json:
+              schema:
+                type: object
+                properties:
+                  status:
+                    type: string
+                    example: db_error
+                  github_client_id:
+                    type: string
+                    example: "your_github_client_id"
   /v0/ping:
     get:
       tags:

scripts/test_endpoints.sh

@@ -77,7 +77,12 @@ test_health() {
   else
     echo "Response:"
     echo "$http_response" | jq '.' 2>/dev/null || echo "$http_response"
-    echo "Health check failed"
+    # Check for db_error in the response
+    if echo "$http_response" | jq -e '.status == "db_error"' >/dev/null 2>&1; then
+      echo "Health check failed: Database connection is unhealthy!"
+    else
+      echo "Health check failed"
+    fi
     echo "-------------------------------------"
     return 1
   fi