fix: enable usestdlibvars linter

Signed-off-by: Matthieu MOREL <matthieu.morel35@gmail.com>

client/internal/v2/auth_role.go

@@ -135,15 +135,15 @@ func (r *httpAuthRoleAPI) AddRole(ctx context.Context, rolename string) error {
 		Role: rolename,
 	}
 	return r.addRemoveRole(ctx, &authRoleAPIAction{
-		verb: "PUT",
+		verb: http.MethodPut,
 		name: rolename,
 		role: role,
 	})
 }
 
 func (r *httpAuthRoleAPI) RemoveRole(ctx context.Context, rolename string) error {
 	return r.addRemoveRole(ctx, &authRoleAPIAction{
-		verb: "DELETE",
+		verb: http.MethodDelete,
 		name: rolename,
 	})
 }
@@ -166,7 +166,7 @@ func (r *httpAuthRoleAPI) addRemoveRole(ctx context.Context, req *authRoleAPIAct
 
 func (r *httpAuthRoleAPI) GetRole(ctx context.Context, rolename string) (*Role, error) {
 	return r.modRole(ctx, &authRoleAPIAction{
-		verb: "GET",
+		verb: http.MethodGet,
 		name: rolename,
 	})
 }
@@ -194,7 +194,7 @@ func (r *httpAuthRoleAPI) GrantRoleKV(ctx context.Context, rolename string, pref
 		},
 	}
 	return r.modRole(ctx, &authRoleAPIAction{
-		verb: "PUT",
+		verb: http.MethodPut,
 		name: rolename,
 		role: role,
 	})
@@ -209,7 +209,7 @@ func (r *httpAuthRoleAPI) RevokeRoleKV(ctx context.Context, rolename string, pre
 		},
 	}
 	return r.modRole(ctx, &authRoleAPIAction{
-		verb: "PUT",
+		verb: http.MethodPut,
 		name: rolename,
 		role: role,
 	})

client/internal/v2/auth_user.go

@@ -74,11 +74,11 @@ type httpAuthAPI struct {
 }
 
 func (s *httpAuthAPI) Enable(ctx context.Context) error {
-	return s.enableDisable(ctx, &authAPIAction{"PUT"})
+	return s.enableDisable(ctx, &authAPIAction{http.MethodPut})
 }
 
 func (s *httpAuthAPI) Disable(ctx context.Context) error {
-	return s.enableDisable(ctx, &authAPIAction{"DELETE"})
+	return s.enableDisable(ctx, &authAPIAction{http.MethodDelete})
 }
 
 func (s *httpAuthAPI) enableDisable(ctx context.Context, req httpAction) error {
@@ -217,15 +217,15 @@ func (u *httpAuthUserAPI) AddUser(ctx context.Context, username string, password
 		Password: password,
 	}
 	return u.addRemoveUser(ctx, &authUserAPIAction{
-		verb:     "PUT",
+		verb:     http.MethodPut,
 		username: username,
 		user:     user,
 	})
 }
 
 func (u *httpAuthUserAPI) RemoveUser(ctx context.Context, username string) error {
 	return u.addRemoveUser(ctx, &authUserAPIAction{
-		verb:     "DELETE",
+		verb:     http.MethodDelete,
 		username: username,
 	})
 }
@@ -248,7 +248,7 @@ func (u *httpAuthUserAPI) addRemoveUser(ctx context.Context, req *authUserAPIAct
 
 func (u *httpAuthUserAPI) GetUser(ctx context.Context, username string) (*User, error) {
 	return u.modUser(ctx, &authUserAPIAction{
-		verb:     "GET",
+		verb:     http.MethodGet,
 		username: username,
 	})
 }
@@ -259,7 +259,7 @@ func (u *httpAuthUserAPI) GrantUser(ctx context.Context, username string, roles
 		Grant: roles,
 	}
 	return u.modUser(ctx, &authUserAPIAction{
-		verb:     "PUT",
+		verb:     http.MethodPut,
 		username: username,
 		user:     user,
 	})
@@ -271,7 +271,7 @@ func (u *httpAuthUserAPI) RevokeUser(ctx context.Context, username string, roles
 		Revoke: roles,
 	}
 	return u.modUser(ctx, &authUserAPIAction{
-		verb:     "PUT",
+		verb:     http.MethodPut,
 		username: username,
 		user:     user,
 	})
@@ -283,7 +283,7 @@ func (u *httpAuthUserAPI) ChangePassword(ctx context.Context, username string, p
 		Password: password,
 	}
 	return u.modUser(ctx, &authUserAPIAction{
-		verb:     "PUT",
+		verb:     http.MethodPut,
 		username: username,
 		user:     user,
 	})

client/internal/v2/client_test.go

@@ -533,7 +533,7 @@ func TestRedirectedHTTPAction(t *testing.T) {
 	act := &redirectedHTTPAction{
 		action: &staticHTTPAction{
 			request: http.Request{
-				Method: "DELETE",
+				Method: http.MethodDelete,
 				URL: &url.URL{
 					Scheme: "https",
 					Host:   "foo.example.com",
@@ -549,7 +549,7 @@ func TestRedirectedHTTPAction(t *testing.T) {
 	}
 
 	want := &http.Request{
-		Method: "DELETE",
+		Method: http.MethodDelete,
 		URL: &url.URL{
 			Scheme: "https",
 			Host:   "bar.example.com",

client/internal/v2/keys_test.go

@@ -162,7 +162,7 @@ func TestGetAction(t *testing.T) {
 		wantURL := baseWantURL
 		wantURL.RawQuery = tt.wantQuery
 
-		err := assertRequest(got, "GET", wantURL, wantHeader, nil)
+		err := assertRequest(got, http.MethodGet, wantURL, wantHeader, nil)
 		if err != nil {
 			t.Errorf("#%d: %v", i, err)
 		}
@@ -211,7 +211,7 @@ func TestWaitAction(t *testing.T) {
 		wantURL := baseWantURL
 		wantURL.RawQuery = tt.wantQuery
 
-		err := assertRequest(got, "GET", wantURL, wantHeader, nil)
+		err := assertRequest(got, http.MethodGet, wantURL, wantHeader, nil)
 		if err != nil {
 			t.Errorf("#%d: unexpected error: %#v", i, err)
 		}
@@ -424,7 +424,7 @@ func TestSetAction(t *testing.T) {
 		}
 
 		got := tt.act.HTTPRequest(url.URL{Scheme: "http", Host: "example.com"})
-		if err := assertRequest(*got, "PUT", u, wantHeader, []byte(tt.wantBody)); err != nil {
+		if err := assertRequest(*got, http.MethodPut, u, wantHeader, []byte(tt.wantBody)); err != nil {
 			t.Errorf("#%d: %v", i, err)
 		}
 	}
@@ -525,7 +525,7 @@ func TestCreateInOrderAction(t *testing.T) {
 		}
 
 		got := tt.act.HTTPRequest(url.URL{Scheme: "http", Host: "example.com"})
-		if err := assertRequest(*got, "POST", u, wantHeader, []byte(tt.wantBody)); err != nil {
+		if err := assertRequest(*got, http.MethodPost, u, wantHeader, []byte(tt.wantBody)); err != nil {
 			t.Errorf("#%d: %v", i, err)
 		}
 	}
@@ -627,7 +627,7 @@ func TestDeleteAction(t *testing.T) {
 		}
 
 		got := tt.act.HTTPRequest(url.URL{Scheme: "http", Host: "example.com"})
-		if err := assertRequest(*got, "DELETE", u, wantHeader, nil); err != nil {
+		if err := assertRequest(*got, http.MethodDelete, u, wantHeader, nil); err != nil {
 			t.Errorf("#%d: %v", i, err)
 		}
 	}

client/internal/v2/members_test.go

@@ -39,7 +39,7 @@ func TestMembersAPIActionList(t *testing.T) {
 	}
 
 	got := *act.HTTPRequest(ep)
-	err := assertRequest(got, "GET", wantURL, http.Header{}, nil)
+	err := assertRequest(got, http.MethodGet, wantURL, http.Header{}, nil)
 	if err != nil {
 		t.Error(err.Error())
 	}
@@ -65,7 +65,7 @@ func TestMembersAPIActionAdd(t *testing.T) {
 	wantBody := []byte(`{"peerURLs":["https://127.0.0.1:8081","http://127.0.0.1:8080"]}`)
 
 	got := *act.HTTPRequest(ep)
-	err := assertRequest(got, "POST", wantURL, wantHeader, wantBody)
+	err := assertRequest(got, http.MethodPost, wantURL, wantHeader, wantBody)
 	if err != nil {
 		t.Error(err.Error())
 	}
@@ -92,7 +92,7 @@ func TestMembersAPIActionUpdate(t *testing.T) {
 	wantBody := []byte(`{"peerURLs":["https://127.0.0.1:8081","http://127.0.0.1:8080"]}`)
 
 	got := *act.HTTPRequest(ep)
-	err := assertRequest(got, "PUT", wantURL, wantHeader, wantBody)
+	err := assertRequest(got, http.MethodPut, wantURL, wantHeader, wantBody)
 	if err != nil {
 		t.Error(err.Error())
 	}
@@ -109,7 +109,7 @@ func TestMembersAPIActionRemove(t *testing.T) {
 	}
 
 	got := *act.HTTPRequest(ep)
-	err := assertRequest(got, "DELETE", wantURL, http.Header{}, nil)
+	err := assertRequest(got, http.MethodDelete, wantURL, http.Header{}, nil)
 	if err != nil {
 		t.Error(err.Error())
 	}
@@ -126,7 +126,7 @@ func TestMembersAPIActionLeader(t *testing.T) {
 	}
 
 	got := *act.HTTPRequest(ep)
-	err := assertRequest(got, "GET", wantURL, http.Header{}, nil)
+	err := assertRequest(got, http.MethodGet, wantURL, http.Header{}, nil)
 	if err != nil {
 		t.Error(err.Error())
 	}

client/pkg/transport/timeout_transport_test.go

@@ -53,7 +53,7 @@ func TestNewTimeoutTransport(t *testing.T) {
 	}
 
 	// ensure not reuse timeout connection
-	req, err := http.NewRequest("GET", srv.URL, nil)
+	req, err := http.NewRequest(http.MethodGet, srv.URL, nil)
 	require.NoError(t, err)
 	resp, err := tr.RoundTrip(req)
 	require.NoError(t, err)

server/embed/serve.go

@@ -436,7 +436,7 @@ func (ac *accessController) ServeHTTP(rw http.ResponseWriter, req *http.Request)
 		addCORSHeader(rw, origin)
 	}
 
-	if req.Method == "OPTIONS" {
+	if req.Method == http.MethodOptions {
 		rw.WriteHeader(http.StatusOK)
 		return
 	}
@@ -486,7 +486,7 @@ func (ch *corsHandler) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
 		addCORSHeader(rw, origin)
 	}
 
-	if req.Method == "OPTIONS" {
+	if req.Method == http.MethodOptions {
 		rw.WriteHeader(http.StatusOK)
 		return
 	}

server/etcdserver/api/etcdhttp/peer_test.go

@@ -172,7 +172,7 @@ func TestServeMembersGet(t *testing.T) {
 	}
 
 	for i, tt := range tests {
-		req, err := http.NewRequest("GET", testutil.MustNewURL(t, tt.path).String(), nil)
+		req, err := http.NewRequest(http.MethodGet, testutil.MustNewURL(t, tt.path).String(), nil)
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -261,7 +261,7 @@ func TestNewPeerHandlerOnMembersPromotePrefix(t *testing.T) {
 		},
 	}
 	for i, tt := range tests {
-		req, err := http.NewRequest("POST", srv.URL+tt.path, nil)
+		req, err := http.NewRequest(http.MethodPost, srv.URL+tt.path, nil)
 		if err != nil {
 			t.Fatalf("failed to create request: %v", err)
 		}

server/etcdserver/api/rafthttp/http.go

@@ -93,7 +93,7 @@ func newPipelineHandler(t *Transport, r Raft, cid types.ID) http.Handler {
 }
 
 func (h *pipelineHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	if r.Method != "POST" {
+	if r.Method != http.MethodPost {
 		w.Header().Set("Allow", "POST")
 		http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
 		return
@@ -200,7 +200,7 @@ const unknownSnapshotSender = "UNKNOWN_SNAPSHOT_SENDER"
 func (h *snapshotHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	start := time.Now()
 
-	if r.Method != "POST" {
+	if r.Method != http.MethodPost {
 		w.Header().Set("Allow", "POST")
 		http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
 		snapshotReceiveFailures.WithLabelValues(unknownSnapshotSender).Inc()
@@ -348,7 +348,7 @@ func newStreamHandler(t *Transport, pg peerGetter, r Raft, id, cid types.ID) htt
 }
 
 func (h *streamHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	if r.Method != "GET" {
+	if r.Method != http.MethodGet {
 		w.Header().Set("Allow", "GET")
 		http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
 		return

server/etcdserver/apply_v2.go

@@ -16,6 +16,7 @@ package etcdserver
 
 import (
 	"encoding/json"
+	"net/http"
 	"path"
 
 	"github.com/coreos/go-semver/semver"
@@ -26,7 +27,7 @@ import (
 )
 
 func (s *EtcdServer) applyV2Request(r *RequestV2, shouldApplyV3 membership.ShouldApplyV3) {
-	if r.Method != "PUT" || (!storeMemberAttributeRegexp.MatchString(r.Path) && r.Path != membership.StoreClusterVersionKey()) {
+	if r.Method != http.MethodPut || (!storeMemberAttributeRegexp.MatchString(r.Path) && r.Path != membership.StoreClusterVersionKey()) {
 		s.lg.Panic("detected disallowed v2 WAL for stage --v2-deprecation=write-only", zap.String("method", r.Method))
 	}
 	if storeMemberAttributeRegexp.MatchString(r.Path) {

server/lease/leasehttp/http.go

@@ -47,7 +47,7 @@ type leaseHandler struct {
 }
 
 func (h *leaseHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	if r.Method != "POST" {
+	if r.Method != http.MethodPost {
 		http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
 		return
 	}

tests/e2e/http_health_check_test.go

@@ -339,7 +339,7 @@ func TestHTTPLivezReadyzHandler(t *testing.T) {
 
 func doHealthCheckAndVerify(t *testing.T, client *http.Client, url string, expectTimeoutError bool, expectStatusCode int, expectRespSubStrings []string) {
 	ctx, cancel := context.WithTimeout(context.Background(), healthCheckTimeout)
-	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
 	require.NoErrorf(t, err, "failed to creat request %+v", err)
 	resp, herr := client.Do(req)
 	cancel()

tests/framework/e2e/etcd_process.go

@@ -363,7 +363,7 @@ func (f *BinaryFailpoints) SetupHTTP(ctx context.Context, failpoint, payload str
 		Host:   host,
 		Path:   failpoint,
 	}
-	r, err := http.NewRequestWithContext(ctx, "PUT", failpointURL.String(), bytes.NewBuffer([]byte(payload)))
+	r, err := http.NewRequestWithContext(ctx, http.MethodPut, failpointURL.String(), bytes.NewBuffer([]byte(payload)))
 	if err != nil {
 		return err
 	}
@@ -395,7 +395,7 @@ func (f *BinaryFailpoints) DeactivateHTTP(ctx context.Context, failpoint string)
 		Host:   host,
 		Path:   failpoint,
 	}
-	r, err := http.NewRequestWithContext(ctx, "DELETE", failpointURL.String(), nil)
+	r, err := http.NewRequestWithContext(ctx, http.MethodDelete, failpointURL.String(), nil)
 	if err != nil {
 		return err
 	}

tools/.golangci.yaml

@@ -30,6 +30,7 @@ linters:
     - unconvert # Remove unnecessary type conversions
     - unparam
     - unused
+    - usestdlibvars
     - whitespace
 linters-settings: # please keep this alphabetized
   goimports:

tools/etcd-dump-logs/etcd-dump-log_test.go

@@ -139,9 +139,9 @@ func appendNormalRequestEnts(ents *[]raftpb.Entry) {
 
 	requests := []etcdserverpb.Request{
 		{ID: 0, Method: "", Path: "/path0", Val: "{\"hey\":\"ho\",\"hi\":[\"yo\"]}", Dir: true, PrevValue: "", PrevIndex: 0, PrevExist: &b, Expiration: 9, Wait: false, Since: 1, Recursive: false, Sorted: false, Quorum: false, Time: 1, Stream: false, Refresh: &b},
-		{ID: 1, Method: "QGET", Path: "/path1", Val: "{\"0\":\"1\",\"2\":[\"3\"]}", Dir: false, PrevValue: "", PrevIndex: 0, PrevExist: &b, Expiration: 9, Wait: false, Since: 1, Recursive: false, Sorted: false, Quorum: false, Time: 1, Stream: false, Refresh: &b},
-		{ID: 2, Method: "SYNC", Path: "/path2", Val: "{\"0\":\"1\",\"2\":[\"3\"]}", Dir: false, PrevValue: "", PrevIndex: 0, PrevExist: &b, Expiration: 2, Wait: false, Since: 1, Recursive: false, Sorted: false, Quorum: false, Time: 1, Stream: false, Refresh: &b},
-		{ID: 3, Method: "DELETE", Path: "/path3", Val: "{\"hey\":\"ho\",\"hi\":[\"yo\"]}", Dir: false, PrevValue: "", PrevIndex: 0, PrevExist: &a, Expiration: 2, Wait: false, Since: 1, Recursive: false, Sorted: false, Quorum: false, Time: 1, Stream: false, Refresh: &b},
+		{ID: 1, Method: MethodQGet, Path: "/path1", Val: "{\"0\":\"1\",\"2\":[\"3\"]}", Dir: false, PrevValue: "", PrevIndex: 0, PrevExist: &b, Expiration: 9, Wait: false, Since: 1, Recursive: false, Sorted: false, Quorum: false, Time: 1, Stream: false, Refresh: &b},
+		{ID: 2, Method: MethodSync, Path: "/path2", Val: "{\"0\":\"1\",\"2\":[\"3\"]}", Dir: false, PrevValue: "", PrevIndex: 0, PrevExist: &b, Expiration: 2, Wait: false, Since: 1, Recursive: false, Sorted: false, Quorum: false, Time: 1, Stream: false, Refresh: &b},
+		{ID: 3, Method: MethodDelete, Path: "/path3", Val: "{\"hey\":\"ho\",\"hi\":[\"yo\"]}", Dir: false, PrevValue: "", PrevIndex: 0, PrevExist: &a, Expiration: 2, Wait: false, Since: 1, Recursive: false, Sorted: false, Quorum: false, Time: 1, Stream: false, Refresh: &b},
 		{ID: 4, Method: "RANDOM", Path: "/path4/superlong" + strings.Repeat("/path", 30), Val: "{\"hey\":\"ho\",\"hi\":[\"yo\"]}", Dir: false, PrevValue: "", PrevIndex: 0, PrevExist: &b, Expiration: 2, Wait: false, Since: 1, Recursive: false, Sorted: false, Quorum: false, Time: 1, Stream: false, Refresh: &b},
 	}
 

tools/etcd-dump-logs/main.go

@@ -41,6 +41,9 @@ import (
 
 const (
 	defaultEntryTypes string = "Normal,ConfigChange"
+	MethodSync        string = "SYNC"
+	MethodQGet        string = "QGET"
+	MethodDelete      string = "DELETE"
 )
 
 func main() {
@@ -292,9 +295,9 @@ func printRequest(entry raftpb.Entry) {
 		switch r.Method {
 		case "":
 			fmt.Print("\tnoop")
-		case "SYNC":
+		case MethodSync:
 			fmt.Printf("\tmethod=SYNC time=%q", time.Unix(0, r.Time).UTC())
-		case "QGET", "DELETE":
+		case MethodQGet, MethodDelete:
 			fmt.Printf("\tmethod=%s path=%s", r.Method, excerpt(r.Path, 64, 64))
 		default:
 			fmt.Printf("\tmethod=%s path=%s val=%s", r.Method, excerpt(r.Path, 64, 64), excerpt(r.Val, 128, 0))