Add api.Config{App} option, to pass in Echo instance

api/api.go

@@ -25,6 +25,8 @@ import (
 )
 
 type Config struct {
+	// If not provided, create an echo.New.
+	App                    *echo.Echo
 	Logger                 *logrus.Entry
 	LoggingMiddlwareConfig LoggingMiddlwareConfig
 	// Origins for echo's CORS middleware.
@@ -82,7 +84,10 @@ func New(cfg Config) *echo.Echo {
 	if cfg.StatusPath == "" {
 		cfg.StatusPath = StatusPath
 	}
-	e := echo.New()
+	e := cfg.App
+	if e == nil {
+		e = echo.New()
+	}
 	e.Logger.SetOutput(os.Stdout)
 	e.HideBanner = true
 	e.HTTPErrorHandler = NewHTTPErrorHandler(e)

api/api_test.go

@@ -83,6 +83,12 @@ var _ = Describe("API", func() {
 		Expect(Serve(e, GetRequest("/statusz"))).To(HaveResponseCode(200))
 	})
 
+	It("can use the provided echo instance", func() {
+		e1 := echo.New()
+		e2 := api.New(api.Config{App: e1})
+		Expect(e2).To(BeIdenticalTo(e1))
+	})
+
 	Describe("tracing", func() {
 		It("uses the trace id in the Trace-Id header", func() {
 			req := GetRequest("/healthz")