Add test for error handler

kylecarbs · kylecarbs · commit 0a63becfd653 · 2022-06-03T04:27:54.000Z
diff --git a/coderd/workspaceapps.go b/coderd/workspaceapps.go
@@ -18,6 +18,8 @@ import (
 	"github.com/coder/coder/site"
 )
 
+// workspaceAppsProxyPath proxies requests to a workspace application
+// through a relative URL path.
 func (api *API) workspaceAppsProxyPath(rw http.ResponseWriter, r *http.Request) {
 	user := httpmw.UserParam(r)
 	// This can be in the form of: "<workspace-name>.[workspace-agent]" or "<workspace-name>"
@@ -115,12 +117,15 @@ func (api *API) workspaceAppsProxyPath(rw http.ResponseWriter, r *http.Request)
 	}
 
 	proxy := httputil.NewSingleHostReverseProxy(appURL)
-	// Write an error using our embed handler
 	proxy.ErrorHandler = func(w http.ResponseWriter, r *http.Request, err error) {
+		// This is a browser-facing route so JSON responses are not viable here.
+		// To pass friendly errors to the frontend, special meta tags are overridden
+		// in the index.html with the content passed here.
 		r = r.WithContext(site.WithAPIResponse(r.Context(), site.APIResponse{
 			StatusCode: http.StatusBadGateway,
 			Message:    err.Error(),
 		}))
+		w.WriteHeader(http.StatusBadGateway)
 		api.siteHandler.ServeHTTP(w, r)
 	}
 	path := chi.URLParam(r, "*")
diff --git a/coderd/workspaceapps_test.go b/coderd/workspaceapps_test.go
@@ -57,6 +57,9 @@ func TestWorkspaceAppsProxyPath(t *testing.T) {
 							Apps: []*proto.App{{
 								Name: "example",
 								Url:  fmt.Sprintf("http://127.0.0.1:%d?query=true", tcpAddr.Port),
+							}, {
+								Name: "fake",
+								Url:  "http://127.0.0.2",
 							}},
 						}},
 					}},
@@ -111,4 +114,12 @@ func TestWorkspaceAppsProxyPath(t *testing.T) {
 		require.Equal(t, "", string(body))
 		require.Equal(t, http.StatusOK, resp.StatusCode)
 	})
+
+	t.Run("ProxyError", func(t *testing.T) {
+		t.Parallel()
+		resp, err := client.Request(context.Background(), http.MethodGet, "/@me/"+workspace.Name+"/apps/fake/", nil)
+		require.NoError(t, err)
+		defer resp.Body.Close()
+		require.Equal(t, http.StatusBadGateway, resp.StatusCode)
+	})
 }
diff --git a/site/site.go b/site/site.go
@@ -134,7 +134,11 @@ func (h *handler) ServeHTTP(resp http.ResponseWriter, req *http.Request) {
 
 	apiResponseRaw := req.Context().Value(apiResponseContextKey{})
 	if apiResponseRaw != nil {
-		state.APIResponse = apiResponseRaw.(APIResponse)
+		apiResponse, ok := apiResponseRaw.(APIResponse)
+		if !ok {
+			panic("dev error: api response in context isn't the correct type")
+		}
+		state.APIResponse = apiResponse
 	}
 
 	// First check if it's a file we have in our templates
