fix: return 404 instead of links page on bad /api/v2 requests (#21950)

* fix: return 404 instead of links page on bad /api/v2 requests

* chore: update CHANGELOG

CHANGELOG.md

@@ -68,6 +68,7 @@ This release adds an embedded SQLite database for storing metadata required by t
 1. [21850](https://github.com/influxdata/influxdb/pull/21850): Systemd unit should block on startup until http endpoint is ready
 1. [21925](https://github.com/influxdata/influxdb/pull/21925): Upgrade to golang-jwt 3.2.1.
 1. [21946](https://github.com/influxdata/influxdb/pull/21946): Prevent silently dropped writes when there are overlapping shards.
+1. [21950](https://github.com/influxdata/influxdb/pull/21950): Invalid requests to /api/v2 subroutes now return 404 instead of a list of links.
 
 ## v2.0.7 [2021-06-04]
 

http/api_handler.go

@@ -140,7 +140,7 @@ func NewAPIHandler(b *APIBackend, opts ...APIHandlerOptFn) *APIHandler {
 
 	b.UserResourceMappingService = authorizer.NewURMService(b.OrgLookupService, b.UserResourceMappingService)
 
-	h.Mount("/api/v2", serveLinksHandler(b.HTTPErrorHandler))
+	h.Handle("/api/v2", serveLinksHandler(b.HTTPErrorHandler))
 
 	checkBackend := NewCheckBackend(b.Logger.With(zap.String("handler", "check")), b)
 	checkBackend.CheckService = authorizer.NewCheckService(b.CheckService,

http/api_handler_test.go

@@ -11,11 +11,66 @@ import (
 	"github.com/google/go-cmp/cmp"
 	kithttp "github.com/influxdata/influxdb/v2/kit/transport/http"
 	"github.com/influxdata/influxdb/v2/pkg/httpc"
+	"github.com/stretchr/testify/require"
 	"github.com/yudai/gojsondiff"
 	"github.com/yudai/gojsondiff/formatter"
 	"go.uber.org/zap/zaptest"
 )
 
+func TestAPIHandlerServeLinks(t *testing.T) {
+	tests := []struct {
+		name   string
+		path   string
+		method string
+		want   int
+	}{
+		{
+			name:   "correct path - GET",
+			path:   "/api/v2",
+			method: "GET",
+			want:   http.StatusOK,
+		},
+		{
+			name:   "correct path with slash - GET",
+			path:   "/api/v2/",
+			method: "GET",
+			want:   http.StatusOK,
+		},
+		{
+			name:   "correct path - POST",
+			path:   "/api/v2",
+			method: "POST",
+			want:   http.StatusOK,
+		},
+		{
+			name:   "incorrect arbitrary path",
+			path:   "/api/v2/asdf",
+			method: "GET",
+			want:   http.StatusNotFound,
+		},
+		{
+			// regression test for https://github.com/influxdata/influxdb/issues/21620
+			name:   "incorrect path at a subroute",
+			path:   "/api/v2/query&foo=bar",
+			method: "GET",
+			want:   http.StatusNotFound,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			r := httptest.NewRequest(tt.method, tt.path, nil)
+			w := httptest.NewRecorder()
+			h := NewAPIHandler(&APIBackend{Logger: zaptest.NewLogger(t)})
+
+			h.ServeHTTP(w, r)
+
+			res := w.Result()
+			require.Equal(t, tt.want, res.StatusCode)
+		})
+	}
+}
+
 func TestAPIHandler_NotFound(t *testing.T) {
 	type args struct {
 		method string