Plugins: Preserve trailing slash in plugin proxy (#86859)

* Plugins: Preserve trailing slash in plugin proxy

* enable toggle by default

docs/sources/setup-grafana/configure-grafana/feature-toggles/index.md

@@ -64,6 +64,7 @@ Most [generally available](https://grafana.com/docs/release-life-cycle/#general-
 | `alertingQueryOptimization`          | Optimizes eligible queries in order to reduce load on datasources                                                                                                                                                            |                    |
 | `betterPageScrolling`                | Removes CustomScrollbar from the UI, relying on native browser scrollbars                                                                                                                                                    | Yes                |
 | `cloudWatchNewLabelParsing`          | Updates CloudWatch label parsing to be more accurate                                                                                                                                                                         | Yes                |
+| `pluginProxyPreserveTrailingSlash`   | Preserve plugin proxy trailing slash.                                                                                                                                                                                        | Yes                |
 
 ## Public preview feature toggles
 

packages/grafana-data/src/types/featureToggles.gen.ts

@@ -190,4 +190,5 @@ export interface FeatureToggles {
   alertingDisableSendAlertsExternal?: boolean;
   preserveDashboardStateWhenNavigating?: boolean;
   alertingCentralAlertHistory?: boolean;
+  pluginProxyPreserveTrailingSlash?: boolean;
 }

pkg/api/plugin_proxy_test.go

@@ -27,6 +27,10 @@ func TestExtractPluginProxyPath(t *testing.T) {
 			"/api/plugin-proxy/cloudflare-app/with-token/api/v4/accounts",
 			"with-token/api/v4/accounts",
 		},
+		{
+			"/api/plugin-proxy/cloudflare-app/with-token/api/v4/accounts/",
+			"with-token/api/v4/accounts/",
+		},
 	}
 	for _, tc := range testCases {
 		t.Run("Given raw path, should extract expected proxy path", func(t *testing.T) {

pkg/api/pluginproxy/ds_proxy_test.go

@@ -104,6 +104,10 @@ func TestDataSourceProxy_routeRule(t *testing.T) {
 				URL:  "http://www.test.com",
 				Body: []byte(`{ "url": "{{.JsonData.dynamicUrl}}", "secret": "{{.SecureJsonData.key}}"	}`),
 			},
+			{
+				Path: "mypath",
+				URL:  "https://example.com/api/v1/",
+			},
 		}
 
 		ds := &datasources.DataSource{
@@ -209,6 +213,16 @@ func TestDataSourceProxy_routeRule(t *testing.T) {
 			require.Equal(t, `{ "url": "https://dynamic.grafana.com", "secret": "123"	}`, string(content))
 		})
 
+		t.Run("When matching route path ending with a slash", func(t *testing.T) {
+			ctx, req := setUp()
+			proxy, err := setupDSProxyTest(t, ctx, ds, routes, "mypath/some-route/")
+			require.NoError(t, err)
+			proxy.matchedRoute = routes[6]
+			ApplyRoute(proxy.ctx.Req.Context(), req, proxy.proxyPath, proxy.matchedRoute, dsInfo, proxy.cfg)
+
+			assert.Equal(t, "https://example.com/api/v1/some-route/", req.URL.String())
+		})
+
 		t.Run("Validating request", func(t *testing.T) {
 			t.Run("plugin route with valid role", func(t *testing.T) {
 				ctx, _ := setUp()

pkg/api/pluginproxy/pluginproxy.go

@@ -6,6 +6,7 @@ import (
 	"io"
 	"net/http"
 	"net/url"
+	"strings"
 
 	"go.opentelemetry.io/otel/attribute"
 
@@ -76,7 +77,12 @@ func (proxy *PluginProxy) HandleRequest() {
 		}
 
 		if path, exists := params["*"]; exists {
+			hasSlash := strings.HasSuffix(proxy.proxyPath, "/")
 			proxy.proxyPath = path
+
+			if hasSlash && !strings.HasSuffix(path, "/") && proxy.features.IsEnabled(proxy.ctx.Req.Context(), featuremgmt.FlagPluginProxyPreserveTrailingSlash) {
+				proxy.proxyPath += "/"
+			}
 		} else {
 			proxy.proxyPath = ""
 		}

pkg/api/pluginproxy/pluginproxy_test.go

@@ -316,10 +316,16 @@ func TestPluginProxyRoutes(t *testing.T) {
 			Method: "GET",
 			URL:    "http://localhost/api/v2/instances",
 		},
+		{
+			Path:   "/mypath/*",
+			Method: "GET",
+			URL:    "https://example.com/api/v1/",
+		},
 	}
 
 	tcs := []struct {
 		proxyPath       string
+		withFeatures    []any
 		expectedURLPath string
 		expectedStatus  int
 	}{
@@ -362,6 +368,17 @@ func TestPluginProxyRoutes(t *testing.T) {
 			expectedURLPath: "/api/v2/instances/instance-one",
 			expectedStatus:  http.StatusOK,
 		},
+		{
+			proxyPath:       "/mypath/some-route/",
+			expectedURLPath: "/api/v1/some-route",
+			expectedStatus:  http.StatusOK,
+		},
+		{
+			proxyPath:       "/mypath/some-route/",
+			withFeatures:    []any{featuremgmt.FlagPluginProxyPreserveTrailingSlash},
+			expectedURLPath: "/api/v1/some-route/",
+			expectedStatus:  http.StatusOK,
+		},
 	}
 
 	for _, tc := range tcs {
@@ -404,7 +421,7 @@ func TestPluginProxyRoutes(t *testing.T) {
 				SecureJSONData: map[string][]byte{},
 			}
 			cfg := &setting.Cfg{}
-			proxy, err := NewPluginProxy(ps, testRoutes, ctx, tc.proxyPath, cfg, secretsService, tracing.InitializeTracerForTest(), &http.Transport{}, acimpl.ProvideAccessControl(featuremgmt.WithFeatures()), featuremgmt.WithFeatures())
+			proxy, err := NewPluginProxy(ps, testRoutes, ctx, tc.proxyPath, cfg, secretsService, tracing.InitializeTracerForTest(), &http.Transport{}, acimpl.ProvideAccessControl(featuremgmt.WithFeatures()), featuremgmt.WithFeatures(tc.withFeatures...))
 			require.NoError(t, err)
 			proxy.HandleRequest()
 

pkg/services/datasourceproxy/datasourceproxy_test.go

@@ -57,6 +57,10 @@ func TestDataProxy(t *testing.T) {
 				"/api/datasources/proxy/uid/26MI0wZ7k/api/services/afsd%2Fafsd/operations",
 				"api/services/afsd%2Fafsd/operations",
 			},
+			{
+				"/api/datasources/proxy/uid/26MI0wZ7k/api/services/afsd%2Fafsd/operations/",
+				"api/services/afsd%2Fafsd/operations/",
+			},
 		}
 		for _, tc := range testCases {
 			t.Run("Given raw path, should extract expected proxy path", func(t *testing.T) {

pkg/services/featuremgmt/registry.go

@@ -1285,6 +1285,13 @@ var (
 			Owner:        grafanaAlertingSquad,
 			FrontendOnly: true,
 		},
+		{
+			Name:        "pluginProxyPreserveTrailingSlash",
+			Description: "Preserve plugin proxy trailing slash.",
+			Stage:       FeatureStageGeneralAvailability,
+			Owner:       grafanaPluginsPlatformSquad,
+			Expression:  "true", // enabled by default
+		},
 	}
 )
 

pkg/services/featuremgmt/toggles_gen.csv

@@ -171,3 +171,4 @@ datasourceProxyDisableRBAC,GA,@grafana/identity-access-team,false,false,false
 alertingDisableSendAlertsExternal,experimental,@grafana/alerting-squad,false,false,false
 preserveDashboardStateWhenNavigating,experimental,@grafana/dashboards-squad,false,false,false
 alertingCentralAlertHistory,experimental,@grafana/alerting-squad,false,false,true
+pluginProxyPreserveTrailingSlash,GA,@grafana/plugins-platform-backend,false,false,false

pkg/services/featuremgmt/toggles_gen.go

@@ -694,4 +694,8 @@ const (
 	// FlagAlertingCentralAlertHistory
 	// Enables the new central alert history.
 	FlagAlertingCentralAlertHistory = "alertingCentralAlertHistory"
+
+	// FlagPluginProxyPreserveTrailingSlash
+	// Preserve plugin proxy trailing slash.
+	FlagPluginProxyPreserveTrailingSlash = "pluginProxyPreserveTrailingSlash"
 )

pkg/services/featuremgmt/toggles_gen.json

@@ -2212,6 +2212,18 @@
         "stage": "GA",
         "codeowner": "@grafana/observability-logs"
       }
+    },
+    {
+      "metadata": {
+        "name": "pluginProxyPreserveTrailingSlash",
+        "resourceVersion": "1717581171624",
+        "creationTimestamp": "2024-06-05T09:52:51Z"
+      },
+      "spec": {
+        "description": "Preserve plugin proxy trailing slash.",
+        "stage": "GA",
+        "codeowner": "@grafana/plugins-platform-backend"
+      }
     }
   ]
 }