feat(api): add dummy root route pointing to docs (#1099)

* feat(api): added dummy root route pointing to docs

* test(api): root request test added

* feat(api): added NoContent return for favicon

from @gulien

Co-authored-by: Julien Neuhart <neuhart.julien@gmail.com>

* test(api): added favicon

* lint(api): fix format

* refactor(api): use %s for favicon.ico for consistency with /health

* test(api): added new recorder for each check

* docs(api): consistent comment for favicon

---------

Co-authored-by: Julien Neuhart <neuhart.julien@gmail.com>

pkg/modules/api/api.go

@@ -483,6 +483,22 @@ func (a *Api) Start() error {
 		)
 	}
 
+	// Root route.
+	a.srv.GET(
+		a.rootPath,
+		func(c echo.Context) error {
+			return c.HTML(http.StatusOK, `Hey, this Gotenberg has no UI, it's an API. Head to the <a href="https://gotenberg.dev">documentation</a> to learn how to interact with it 🚀`)
+		},
+	)
+
+	// Favicon route.
+	a.srv.GET(
+		fmt.Sprintf("%s%s", a.rootPath, "favicon.ico"),
+		func(c echo.Context) error {
+			return c.NoContent(http.StatusNoContent)
+		},
+	)
+
 	// Let's not forget the health check routes...
 	checks := append(a.healthChecks, health.WithTimeout(a.timeout))
 	checker := health.NewChecker(checks...)

pkg/modules/api/api_test.go

@@ -866,15 +866,31 @@ func TestApi_Start(t *testing.T) {
 				return
 			}
 
-			// health requests.
+			// root request.
 			recorder := httptest.NewRecorder()
+			rootRequest := httptest.NewRequest(http.MethodGet, "/", nil)
+			mod.srv.ServeHTTP(recorder, rootRequest)
+			if recorder.Code != http.StatusOK {
+				t.Errorf("expected %d status code but got %d", http.StatusOK, recorder.Code)
+			}
 
+			// favicon request.
+			recorder = httptest.NewRecorder()
+			faviconRequest := httptest.NewRequest(http.MethodGet, "/favicon.ico", nil)
+			mod.srv.ServeHTTP(recorder, faviconRequest)
+			if recorder.Code != http.StatusNoContent {
+				t.Errorf("expected %d status code but got %d", http.StatusNoContent, recorder.Code)
+			}
+
+			// health requests.
+			recorder = httptest.NewRecorder()
 			healthGetRequest := httptest.NewRequest(http.MethodGet, "/health", nil)
 			mod.srv.ServeHTTP(recorder, healthGetRequest)
 			if recorder.Code != http.StatusOK {
 				t.Errorf("expected %d status code but got %d", http.StatusOK, recorder.Code)
 			}
 
+			recorder = httptest.NewRecorder()
 			healthHeadRequest := httptest.NewRequest(http.MethodHead, "/health", nil)
 			mod.srv.ServeHTTP(recorder, healthHeadRequest)
 			if recorder.Code != http.StatusOK {
@@ -882,6 +898,7 @@ func TestApi_Start(t *testing.T) {
 			}
 
 			// version request.
+			recorder = httptest.NewRecorder()
 			versionRequest := httptest.NewRequest(http.MethodGet, "/version", nil)
 			mod.srv.ServeHTTP(recorder, versionRequest)
 			if recorder.Code != http.StatusOK {