ShortURL: Implement /goto with a sub-resource (#110972)

apps/shorturl/pkg/app/app.go

@@ -2,17 +2,23 @@ package app
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
+	"net/http"
 	"path"
 	"strings"
+	"time"
 
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/klog/v2"
 
 	"github.com/grafana/grafana-app-sdk/app"
+	"github.com/grafana/grafana-app-sdk/k8s"
+	"github.com/grafana/grafana-app-sdk/logging"
 	"github.com/grafana/grafana-app-sdk/resource"
 	"github.com/grafana/grafana-app-sdk/simple"
 	shorturlv1alpha1 "github.com/grafana/grafana/apps/shorturl/pkg/apis/shorturl/v1alpha1"
+	"github.com/grafana/grafana/pkg/apimachinery/identity"
 )
 
 // Local error definitions to avoid importing the main shorturls package
@@ -21,17 +27,21 @@ var (
 	ErrShortURLInvalidPath  = fmt.Errorf("invalid short URL path")
 )
 
-type ShortURLConfig struct {
-	AppURL string
-}
+type ShortURLConfig struct{}
 
 func New(cfg app.Config) (app.App, error) {
-	// Extract the AppURL from the specific config
 	shortURLConfig, ok := cfg.SpecificConfig.(*ShortURLConfig)
 	if !ok || shortURLConfig == nil {
 		return nil, fmt.Errorf("invalid or missing ShortURLConfig")
 	}
 
+	cfg.KubeConfig.APIPath = "apis"
+	client, err := k8s.NewClientRegistry(cfg.KubeConfig, k8s.DefaultClientConfig()).
+		ClientFor(shorturlv1alpha1.ShortURLKind())
+	if err != nil {
+		return nil, fmt.Errorf("unable to create client")
+	}
+
 	simpleConfig := simple.AppConfig{
 		Name:       "shorturl",
 		KubeConfig: cfg.KubeConfig,
@@ -61,6 +71,47 @@ func New(cfg app.Config) (app.App, error) {
 						return nil
 					},
 				},
+				CustomRoutes: simple.AppCustomRouteHandlers{
+					simple.AppCustomRoute{
+						Method: "GET",
+						Path:   "goto",
+					}: func(ctx context.Context, w app.CustomRouteResponseWriter, req *app.CustomRouteRequest) error {
+						url, _, found := strings.Cut(req.URL.Path, "/apis/") // This will be settings.AppURL
+						if !found {
+							return fmt.Errorf("unable to parse request URL")
+						}
+						id := resource.Identifier{
+							Namespace: req.ResourceIdentifier.Namespace,
+							Name:      req.ResourceIdentifier.Name,
+						}
+
+						info := &shorturlv1alpha1.ShortURL{}
+						if err := client.GetInto(ctx, id, info); err != nil {
+							return err
+						}
+
+						// Update lastSeenAt in the background
+						func() { // TODO, this should be async, but keeping sync until we update tests
+							info.Status.LastSeenAt = time.Now().UnixMilli()
+							ctx, _, err := identity.WithProvisioningIdentity(context.Background(), req.ResourceIdentifier.Namespace)
+							if err != nil {
+								logging.FromContext(ctx).Warn("unable to create background identity", "err", err)
+							} else {
+								_, _ = client.Update(ctx, id, info, resource.UpdateOptions{})
+							}
+						}()
+
+						url = url + "/" + info.Spec.Path
+						if req.URL.Query().Get("redirect") == "false" { // helpful for testing
+							return json.NewEncoder(w).Encode(shorturlv1alpha1.GetGoto{
+								Url: url,
+							})
+						}
+						w.Header().Add("Location", url)
+						w.WriteHeader(http.StatusFound)
+						return nil
+					},
+				},
 			},
 		},
 	}