golangci-lint: enable usestdlibvars linter

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

.golangci.yml

@@ -26,6 +26,7 @@ linters:
     - testifylint
     - unconvert
     - unused
+    - usestdlibvars
 
 issues:
   max-same-issues: 0

cmd/promtool/main.go

@@ -482,7 +482,7 @@ func CheckServerStatus(serverURL *url.URL, checkEndpoint string, roundTripper ht
 		return err
 	}
 
-	request, err := http.NewRequest("GET", config.Address, nil)
+	request, err := http.NewRequest(http.MethodGet, config.Address, nil)
 	if err != nil {
 		return err
 	}

discovery/eureka/client.go

@@ -81,7 +81,7 @@ const appListPath string = "/apps"
 func fetchApps(ctx context.Context, server string, client *http.Client) (*Applications, error) {
 	url := fmt.Sprintf("%s%s", server, appListPath)
 
-	request, err := http.NewRequest("GET", url, nil)
+	request, err := http.NewRequest(http.MethodGet, url, nil)
 	if err != nil {
 		return nil, err
 	}

discovery/hetzner/robot.go

@@ -70,7 +70,7 @@ func newRobotDiscovery(conf *SDConfig, _ log.Logger) (*robotDiscovery, error) {
 }
 
 func (d *robotDiscovery) refresh(context.Context) ([]*targetgroup.Group, error) {
-	req, err := http.NewRequest("GET", d.endpoint+"/server", nil)
+	req, err := http.NewRequest(http.MethodGet, d.endpoint+"/server", nil)
 	if err != nil {
 		return nil, err
 	}

discovery/http/http.go

@@ -150,7 +150,7 @@ func NewDiscovery(conf *SDConfig, logger log.Logger, clientOpts []config.HTTPCli
 }
 
 func (d *Discovery) Refresh(ctx context.Context) ([]*targetgroup.Group, error) {
-	req, err := http.NewRequest("GET", d.url, nil)
+	req, err := http.NewRequest(http.MethodGet, d.url, nil)
 	if err != nil {
 		return nil, err
 	}

discovery/marathon/marathon.go

@@ -339,7 +339,7 @@ type appListClient func(ctx context.Context, client *http.Client, url string) (*
 
 // fetchApps requests a list of applications from a marathon server.
 func fetchApps(ctx context.Context, client *http.Client, url string) (*appList, error) {
-	request, err := http.NewRequest("GET", url, nil)
+	request, err := http.NewRequest(http.MethodGet, url, nil)
 	if err != nil {
 		return nil, err
 	}

discovery/openstack/mock_test.go

@@ -239,7 +239,7 @@ const hypervisorListBody = `
 // HandleHypervisorListSuccessfully mocks os-hypervisors detail call.
 func (m *SDMock) HandleHypervisorListSuccessfully() {
 	m.Mux.HandleFunc("/os-hypervisors/detail", func(w http.ResponseWriter, r *http.Request) {
-		testMethod(m.t, r, "GET")
+		testMethod(m.t, r, http.MethodGet)
 		testHeader(m.t, r, "X-Auth-Token", tokenID)
 
 		w.Header().Add("Content-Type", "application/json")
@@ -536,7 +536,7 @@ const serverListBody = `
 // HandleServerListSuccessfully mocks server detail call.
 func (m *SDMock) HandleServerListSuccessfully() {
 	m.Mux.HandleFunc("/servers/detail", func(w http.ResponseWriter, r *http.Request) {
-		testMethod(m.t, r, "GET")
+		testMethod(m.t, r, http.MethodGet)
 		testHeader(m.t, r, "X-Auth-Token", tokenID)
 
 		w.Header().Add("Content-Type", "application/json")
@@ -575,7 +575,7 @@ const listOutput = `
 // HandleFloatingIPListSuccessfully mocks floating ips call.
 func (m *SDMock) HandleFloatingIPListSuccessfully() {
 	m.Mux.HandleFunc("/os-floating-ips", func(w http.ResponseWriter, r *http.Request) {
-		testMethod(m.t, r, "GET")
+		testMethod(m.t, r, http.MethodGet)
 		testHeader(m.t, r, "X-Auth-Token", tokenID)
 
 		w.Header().Add("Content-Type", "application/json")

discovery/puppetdb/puppetdb.go

@@ -189,7 +189,7 @@ func (d *Discovery) refresh(ctx context.Context) ([]*targetgroup.Group, error) {
 		return nil, err
 	}
 
-	req, err := http.NewRequest("POST", d.url, bytes.NewBuffer(bodyBytes))
+	req, err := http.NewRequest(http.MethodPost, d.url, bytes.NewBuffer(bodyBytes))
 	if err != nil {
 		return nil, err
 	}

discovery/triton/triton.go

@@ -211,7 +211,7 @@ func (d *Discovery) refresh(ctx context.Context) ([]*targetgroup.Group, error) {
 		endpoint = fmt.Sprintf("%s?groups=%s", endpoint, groups)
 	}
 
-	req, err := http.NewRequest("GET", endpoint, nil)
+	req, err := http.NewRequest(http.MethodGet, endpoint, nil)
 	if err != nil {
 		return nil, err
 	}

discovery/xds/client.go

@@ -179,7 +179,7 @@ func (rc *HTTPResourceClient) Fetch(ctx context.Context) (*v3.DiscoveryResponse,
 		return nil, err
 	}
 
-	request, err := http.NewRequest("POST", rc.endpoint, bytes.NewBuffer(reqBody))
+	request, err := http.NewRequest(http.MethodPost, rc.endpoint, bytes.NewBuffer(reqBody))
 	if err != nil {
 		return nil, err
 	}

documentation/examples/remote_storage/remote_storage_adapter/influxdb/client_test.go

@@ -74,7 +74,7 @@ testmetric,test_label=test_label_value2 value=5.1234 123456789123
 
 	server := httptest.NewServer(http.HandlerFunc(
 		func(w http.ResponseWriter, r *http.Request) {
-			require.Equal(t, "POST", r.Method, "Unexpected method.")
+			require.Equal(t, http.MethodPost, r.Method, "Unexpected method.")
 			require.Equal(t, "/write", r.URL.Path, "Unexpected path.")
 			b, err := io.ReadAll(r.Body)
 			require.NoError(t, err, "Error reading body.")

documentation/examples/remote_storage/remote_storage_adapter/opentsdb/client.go

@@ -105,7 +105,7 @@ func (c *Client) Write(samples model.Samples) error {
 	ctx, cancel := context.WithTimeout(context.Background(), c.timeout)
 	defer cancel()
 
-	req, err := http.NewRequest("POST", u.String(), bytes.NewBuffer(buf))
+	req, err := http.NewRequest(http.MethodPost, u.String(), bytes.NewBuffer(buf))
 	if err != nil {
 		return err
 	}

model/labels/labels_test.go

@@ -16,6 +16,7 @@ package labels
 import (
 	"encoding/json"
 	"fmt"
+	"net/http"
 	"strings"
 	"testing"
 
@@ -810,7 +811,7 @@ var benchmarkLabels = []Label{
 	{"job", "node"},
 	{"instance", "123.123.1.211:9090"},
 	{"path", "/api/v1/namespaces/<namespace>/deployments/<name>"},
-	{"method", "GET"},
+	{"method", http.MethodGet},
 	{"namespace", "system"},
 	{"status", "500"},
 	{"prometheus", "prometheus-core-1"},

notifier/notifier.go

@@ -590,7 +590,7 @@ func labelsToOpenAPILabelSet(modelLabelSet labels.Labels) models.LabelSet {
 }
 
 func (n *Manager) sendOne(ctx context.Context, c *http.Client, url string, b []byte) error {
-	req, err := http.NewRequest("POST", url, bytes.NewReader(b))
+	req, err := http.NewRequest(http.MethodPost, url, bytes.NewReader(b))
 	if err != nil {
 		return err
 	}

scrape/scrape.go

@@ -726,7 +726,7 @@ var UserAgent = fmt.Sprintf("Prometheus/%s", version.Version)
 
 func (s *targetScraper) scrape(ctx context.Context) (*http.Response, error) {
 	if s.req == nil {
-		req, err := http.NewRequest("GET", s.URL().String(), nil)
+		req, err := http.NewRequest(http.MethodGet, s.URL().String(), nil)
 		if err != nil {
 			return nil, err
 		}

storage/remote/client.go

@@ -199,7 +199,7 @@ type RecoverableError struct {
 // Store sends a batch of samples to the HTTP endpoint, the request is the proto marshalled
 // and encoded bytes from codec.go.
 func (c *Client) Store(ctx context.Context, req []byte, attempt int) error {
-	httpReq, err := http.NewRequest("POST", c.urlString, bytes.NewReader(req))
+	httpReq, err := http.NewRequest(http.MethodPost, c.urlString, bytes.NewReader(req))
 	if err != nil {
 		// Errors from NewRequest are from unparsable URLs, so are not
 		// recoverable.
@@ -290,7 +290,7 @@ func (c *Client) Read(ctx context.Context, query *prompb.Query) (*prompb.QueryRe
 	}
 
 	compressed := snappy.Encode(nil, data)
-	httpReq, err := http.NewRequest("POST", c.urlString, bytes.NewReader(compressed))
+	httpReq, err := http.NewRequest(http.MethodPost, c.urlString, bytes.NewReader(compressed))
 	if err != nil {
 		return nil, fmt.Errorf("unable to create request: %w", err)
 	}

storage/remote/read_handler_test.go

@@ -75,7 +75,7 @@ func TestSampledReadEndpoint(t *testing.T) {
 	require.NoError(t, err)
 
 	compressed := snappy.Encode(nil, data)
-	request, err := http.NewRequest("POST", "", bytes.NewBuffer(compressed))
+	request, err := http.NewRequest(http.MethodPost, "", bytes.NewBuffer(compressed))
 	require.NoError(t, err)
 
 	recorder := httptest.NewRecorder()
@@ -170,7 +170,7 @@ func BenchmarkStreamReadEndpoint(b *testing.B) {
 
 	for i := 0; i < b.N; i++ {
 		compressed := snappy.Encode(nil, data)
-		request, err := http.NewRequest("POST", "", bytes.NewBuffer(compressed))
+		request, err := http.NewRequest(http.MethodPost, "", bytes.NewBuffer(compressed))
 		require.NoError(b, err)
 
 		recorder := httptest.NewRecorder()
@@ -268,7 +268,7 @@ func TestStreamReadEndpoint(t *testing.T) {
 	require.NoError(t, err)
 
 	compressed := snappy.Encode(nil, data)
-	request, err := http.NewRequest("POST", "", bytes.NewBuffer(compressed))
+	request, err := http.NewRequest(http.MethodPost, "", bytes.NewBuffer(compressed))
 	require.NoError(t, err)
 
 	recorder := httptest.NewRecorder()

util/httputil/compression_test.go

@@ -85,7 +85,7 @@ func TestCompressionHandler_Gzip(t *testing.T) {
 		},
 	}
 
-	req, _ := http.NewRequest("GET", server.URL+"/foo_endpoint", nil)
+	req, _ := http.NewRequest(http.MethodGet, server.URL+"/foo_endpoint", nil)
 	req.Header.Set(acceptEncodingHeader, gzipEncoding)
 
 	resp, err := client.Do(req)
@@ -120,7 +120,7 @@ func TestCompressionHandler_Deflate(t *testing.T) {
 		},
 	}
 
-	req, _ := http.NewRequest("GET", server.URL+"/foo_endpoint", nil)
+	req, _ := http.NewRequest(http.MethodGet, server.URL+"/foo_endpoint", nil)
 	req.Header.Set(acceptEncodingHeader, deflateEncoding)
 
 	resp, err := client.Do(req)

util/httputil/cors_test.go

@@ -41,7 +41,7 @@ func TestCORSHandler(t *testing.T) {
 	dummyOrigin := "https://foo.com"
 
 	// OPTIONS with legit origin
-	req, err := http.NewRequest("OPTIONS", server.URL+"/any_path", nil)
+	req, err := http.NewRequest(http.MethodOptions, server.URL+"/any_path", nil)
 	require.NoError(t, err, "could not create request")
 
 	req.Header.Set("Origin", dummyOrigin)
@@ -53,7 +53,7 @@ func TestCORSHandler(t *testing.T) {
 	require.Equal(t, dummyOrigin, AccessControlAllowOrigin, "expected Access-Control-Allow-Origin header")
 
 	// OPTIONS with bad origin
-	req, err = http.NewRequest("OPTIONS", server.URL+"/any_path", nil)
+	req, err = http.NewRequest(http.MethodOptions, server.URL+"/any_path", nil)
 	require.NoError(t, err, "could not create request")
 
 	req.Header.Set("Origin", "https://not-foo.com")

web/api/v1/api_test.go

@@ -3354,7 +3354,7 @@ func TestParseTimeParam(t *testing.T) {
 	}
 
 	for _, test := range tests {
-		req, err := http.NewRequest("GET", "localhost:42/foo?"+test.paramName+"="+test.paramValue, nil)
+		req, err := http.NewRequest(http.MethodGet, "localhost:42/foo?"+test.paramName+"="+test.paramValue, nil)
 		require.NoError(t, err)
 
 		result := test.result
@@ -3491,7 +3491,7 @@ func TestOptionsMethod(t *testing.T) {
 	s := httptest.NewServer(r)
 	defer s.Close()
 
-	req, err := http.NewRequest("OPTIONS", s.URL+"/any_path", nil)
+	req, err := http.NewRequest(http.MethodOptions, s.URL+"/any_path", nil)
 	require.NoError(t, err, "Error creating OPTIONS request")
 	client := &http.Client{}
 	resp, err := client.Do(req)

web/api/v1/errors_test.go

@@ -89,7 +89,7 @@ func TestApiStatusCodes(t *testing.T) {
 				r := createPrometheusAPI(q)
 				rec := httptest.NewRecorder()
 
-				req := httptest.NewRequest("GET", "/api/v1/query?query=up", nil)
+				req := httptest.NewRequest(http.MethodGet, "/api/v1/query?query=up", nil)
 
 				r.ServeHTTP(rec, req)
 

web/federate_test.go

@@ -224,7 +224,7 @@ func TestFederation(t *testing.T) {
 	for name, scenario := range scenarios {
 		t.Run(name, func(t *testing.T) {
 			h.config.GlobalConfig.ExternalLabels = scenario.externalLabels
-			req := httptest.NewRequest("GET", "http://example.org/federate?"+scenario.params, nil)
+			req := httptest.NewRequest(http.MethodGet, "http://example.org/federate?"+scenario.params, nil)
 			res := httptest.NewRecorder()
 
 			h.federation(res, req)
@@ -265,7 +265,7 @@ func TestFederation_NotReady(t *testing.T) {
 				},
 			}
 
-			req := httptest.NewRequest("GET", "http://example.org/federate?"+scenario.params, nil)
+			req := httptest.NewRequest(http.MethodGet, "http://example.org/federate?"+scenario.params, nil)
 			res := httptest.NewRecorder()
 
 			h.federation(res, req)
@@ -381,7 +381,7 @@ func TestFederationWithNativeHistograms(t *testing.T) {
 		},
 	}
 
-	req := httptest.NewRequest("GET", "http://example.org/federate?match[]=test_metric", nil)
+	req := httptest.NewRequest(http.MethodGet, "http://example.org/federate?match[]=test_metric", nil)
 	req.Header.Add("Accept", `application/vnd.google.protobuf;proto=io.prometheus.client.MetricFamily;encoding=delimited,application/openmetrics-text;version=1.0.0;q=0.8,application/openmetrics-text;version=0.0.1;q=0.75,text/plain;version=0.0.4;q=0.5,*/*;q=0.1`)
 	res := httptest.NewRecorder()
 

web/web_test.go

@@ -311,7 +311,7 @@ func TestDebugHandler(t *testing.T) {
 
 		w := httptest.NewRecorder()
 
-		req, err := http.NewRequest("GET", tc.url, nil)
+		req, err := http.NewRequest(http.MethodGet, tc.url, nil)
 
 		require.NoError(t, err)
 
@@ -335,7 +335,7 @@ func TestHTTPMetrics(t *testing.T) {
 		t.Helper()
 		w := httptest.NewRecorder()
 
-		req, err := http.NewRequest("GET", "/-/ready", nil)
+		req, err := http.NewRequest(http.MethodGet, "/-/ready", nil)
 		require.NoError(t, err)
 
 		handler.router.ServeHTTP(w, req)