[chore]: enable usestdlibvars linter (part 1) (open-telemetry#36009)

#### Description

[usestdlibvars](https://golangci-lint.run/usage/linters/#usestdlibvars)
is a linter that detect the possibility to use variables/constants from
the Go standard library.

Notice that's only the first part, the full conformity wil be ensured
with one or two other PR as this one is already big to review

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

cmd/opampsupervisor/supervisor/healthchecker/healthchecker.go

@@ -23,7 +23,7 @@ func NewHTTPHealthChecker(endpoint string) *HTTPHealthChecker {
 }
 
 func (h *HTTPHealthChecker) Check(ctx context.Context) error {
-	req, err := http.NewRequestWithContext(ctx, "GET", h.endpoint, nil)
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, h.endpoint, nil)
 	if err != nil {
 		return err
 	}

examples/demo/client/main.go

@@ -186,7 +186,7 @@ func makeRequest(ctx context.Context) {
 	}
 
 	// Make sure we pass the context to the request to avoid broken traces.
-	req, err := http.NewRequestWithContext(ctx, "GET", demoServerAddr, nil)
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, demoServerAddr, nil)
 	if err != nil {
 		handleErr(err, "failed to http request")
 	}

exporter/alertmanagerexporter/alertmanager_exporter.go

@@ -132,7 +132,7 @@ func (s *alertmanagerExporter) postAlert(ctx context.Context, payload []model.Al
 		return fmt.Errorf("error marshaling alert to JSON: %w", err)
 	}
 
-	req, err := http.NewRequestWithContext(ctx, "POST", s.endpoint, bytes.NewBuffer(msg))
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, s.endpoint, bytes.NewBuffer(msg))
 	if err != nil {
 		return fmt.Errorf("error creating HTTP request: %w", err)
 	}

exporter/mezmoexporter/exporter.go

@@ -167,7 +167,7 @@ func (m *mezmoExporter) logDataToMezmo(ld plog.Logs) error {
 }
 
 func (m *mezmoExporter) sendLinesToMezmo(post string) (errs error) {
-	req, _ := http.NewRequest("POST", m.config.IngestURL, strings.NewReader(post))
+	req, _ := http.NewRequest(http.MethodPost, m.config.IngestURL, strings.NewReader(post))
 	req.Header.Add("Accept", "application/json")
 	req.Header.Add("Content-Type", "application/json")
 	req.Header.Add("User-Agent", m.userAgentString)

exporter/opensearchexporter/integration_test.go

@@ -116,7 +116,7 @@ func TestOpenSearchTraceExporter(t *testing.T) {
 			assert.LessOrEqualf(t, requestCount, len(tc.RequestHandlers), "Test case generated more requests than it has response for.")
 			tc.RequestHandlers[requestCount].ValidateReceivedDocuments(t, requestCount, docs)
 
-			w.WriteHeader(200)
+			w.WriteHeader(http.StatusOK)
 			response, _ := os.ReadFile(tc.RequestHandlers[requestCount].ResponseJSONPath)
 			_, err = w.Write(response)
 			assert.NoError(t, err)
@@ -246,7 +246,7 @@ func TestOpenSearchLogExporter(t *testing.T) {
 			assert.LessOrEqualf(t, requestCount, len(tc.RequestHandlers), "Test case generated more requests than it has response for.")
 			tc.RequestHandlers[requestCount].ValidateReceivedDocuments(t, requestCount, docs)
 
-			w.WriteHeader(200)
+			w.WriteHeader(http.StatusOK)
 			response, _ := os.ReadFile(tc.RequestHandlers[requestCount].ResponseJSONPath)
 			_, err = w.Write(response)
 			assert.NoError(t, err)

exporter/prometheusremotewriteexporter/exporter.go

@@ -326,7 +326,7 @@ func (prwe *prwExporter) execute(ctx context.Context, writeReq *prompb.WriteRequ
 
 		// 429 errors are recoverable and the exporter should retry if RetryOnHTTP429 enabled
 		// Reference: https://github.com/prometheus/prometheus/pull/12677
-		if prwe.retryOnHTTP429 && resp.StatusCode == 429 {
+		if prwe.retryOnHTTP429 && resp.StatusCode == http.StatusTooManyRequests {
 			return rerr
 		}
 

exporter/sapmexporter/exporter_test.go

@@ -370,7 +370,7 @@ func TestCompression(t *testing.T) {
 							err = sapm.Unmarshal(payload)
 							assert.NoError(t, err)
 
-							w.WriteHeader(200)
+							w.WriteHeader(http.StatusOK)
 							tracesReceived = true
 						},
 					),

exporter/sentryexporter/sentry_exporter_test.go

@@ -8,6 +8,7 @@ import (
 	"encoding/hex"
 	"encoding/json"
 	"errors"
+	"net/http"
 	"testing"
 
 	"github.com/getsentry/sentry-go"
@@ -380,7 +381,7 @@ func TestGenerateSpanDescriptors(t *testing.T) {
 			testName: "http-server",
 			name:     "/api/users/{user_id}",
 			attrs: map[string]any{
-				conventions.AttributeHTTPMethod: "POST",
+				conventions.AttributeHTTPMethod: http.MethodPost,
 			},
 			spanKind:    ptrace.SpanKindServer,
 			op:          "http.server",

exporter/signalfxexporter/internal/apm/correlations/client_test.go

@@ -64,7 +64,7 @@ func makeHandler(t *testing.T, corCh chan<- *request, forcedRespCode *atomic.Val
 		case http.MethodGet:
 			match := getPathRegexp.FindStringSubmatch(r.URL.Path)
 			if len(match) < 3 {
-				rw.WriteHeader(404)
+				rw.WriteHeader(http.StatusNotFound)
 				return
 			}
 			corCh <- &request{
@@ -79,7 +79,7 @@ func makeHandler(t *testing.T, corCh chan<- *request, forcedRespCode *atomic.Val
 		case http.MethodPut:
 			match := putPathRegexp.FindStringSubmatch(r.URL.Path)
 			if len(match) < 4 {
-				rw.WriteHeader(404)
+				rw.WriteHeader(http.StatusNotFound)
 				return
 			}
 
@@ -101,7 +101,7 @@ func makeHandler(t *testing.T, corCh chan<- *request, forcedRespCode *atomic.Val
 		case http.MethodDelete:
 			match := deletePathRegexp.FindStringSubmatch(r.URL.Path)
 			if len(match) < 5 {
-				rw.WriteHeader(404)
+				rw.WriteHeader(http.StatusNotFound)
 				return
 			}
 			cor = &request{
@@ -114,13 +114,13 @@ func makeHandler(t *testing.T, corCh chan<- *request, forcedRespCode *atomic.Val
 				},
 			}
 		default:
-			rw.WriteHeader(404)
+			rw.WriteHeader(http.StatusNotFound)
 			return
 		}
 
 		corCh <- cor
 
-		rw.WriteHeader(200)
+		rw.WriteHeader(http.StatusOK)
 	})
 }
 

exporter/signalfxexporter/internal/dimensions/dimclient_test.go

@@ -63,13 +63,13 @@ func makeHandler(dimCh chan<- dim, forcedResp *atomic.Int32) http.HandlerFunc {
 		log.Printf("Test server got request: %s", r.URL.Path)
 
 		if r.Method != "PATCH" {
-			rw.WriteHeader(404)
+			rw.WriteHeader(http.StatusNotFound)
 			return
 		}
 
 		match := patchPathRegexp.FindStringSubmatch(r.URL.Path)
 		if match == nil {
-			rw.WriteHeader(404)
+			rw.WriteHeader(http.StatusNotFound)
 			return
 		}
 
@@ -83,7 +83,7 @@ func makeHandler(dimCh chan<- dim, forcedResp *atomic.Int32) http.HandlerFunc {
 
 		dimCh <- bodyDim
 
-		rw.WriteHeader(200)
+		rw.WriteHeader(http.StatusOK)
 	}
 }
 

exporter/splunkhecexporter/internal/integrationtestutils/splunk.go

@@ -47,7 +47,7 @@ func getSplunkSearchResults(user string, password string, baseURL string, jobID
 	logger := log.New(os.Stdout, "", log.LstdFlags)
 	eventURL := fmt.Sprintf("%s/services/search/jobs/%s/events?output_mode=json", baseURL, jobID)
 	logger.Println("URL: " + eventURL)
-	reqEvents, err := http.NewRequest("GET", eventURL, nil)
+	reqEvents, err := http.NewRequest(http.MethodGet, eventURL, nil)
 	if err != nil {
 		panic(err)
 	}
@@ -89,7 +89,7 @@ func checkSearchJobStatusCode(user string, password string, baseURL string, jobI
 		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
 	}
 	client := &http.Client{Transport: tr}
-	checkReqEvents, err := http.NewRequest("GET", checkEventURL, nil)
+	checkReqEvents, err := http.NewRequest(http.MethodGet, checkEventURL, nil)
 	if err != nil {
 		panic(err)
 	}
@@ -129,7 +129,7 @@ func postSearchRequest(user string, password string, baseURL string, searchQuery
 		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
 	}
 	client := &http.Client{Transport: tr}
-	req, err := http.NewRequest("POST", searchURL, strings.NewReader(data.Encode()))
+	req, err := http.NewRequest(http.MethodPost, searchURL, strings.NewReader(data.Encode()))
 	if err != nil {
 		logger.Printf("Error while preparing POST request")
 		panic(err)
@@ -172,7 +172,7 @@ func CheckMetricsFromSplunk(index string, metricName string) []any {
 		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
 	}
 	client := &http.Client{Transport: tr, Timeout: 10 * time.Second}
-	req, err := http.NewRequest("GET", apiURL, nil)
+	req, err := http.NewRequest(http.MethodGet, apiURL, nil)
 	if err != nil {
 		panic(err)
 	}
@@ -209,7 +209,7 @@ func CreateAnIndexInSplunk(index string, indexType string) {
 		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
 	}
 	client := &http.Client{Transport: tr}
-	req, err := http.NewRequest("POST", indexURL, strings.NewReader(data.Encode()))
+	req, err := http.NewRequest(http.MethodPost, indexURL, strings.NewReader(data.Encode()))
 	if err != nil {
 		logger.Printf("Error while preparing POST request")
 		panic(err)

exporter/sumologicexporter/sender_test.go

@@ -374,7 +374,7 @@ func TestSendLogsSplitFailedAll(t *testing.T) {
 			assert.Equal(t, "Example log", body)
 		},
 		func(w http.ResponseWriter, req *http.Request) {
-			w.WriteHeader(404)
+			w.WriteHeader(http.StatusNotFound)
 
 			body := extractBody(t, req)
 			assert.Equal(t, "Another example log", body)
@@ -741,7 +741,7 @@ func TestSendLogsJsonSplitFailedAll(t *testing.T) {
 			assert.Regexp(t, regex, body)
 		},
 		func(w http.ResponseWriter, req *http.Request) {
-			w.WriteHeader(404)
+			w.WriteHeader(http.StatusNotFound)
 
 			body := extractBody(t, req)
 
@@ -984,7 +984,7 @@ func TestInvalidPipeline(t *testing.T) {
 func TestSendCompressGzip(t *testing.T) {
 	test := prepareSenderTest(t, configcompression.TypeGzip, []func(res http.ResponseWriter, req *http.Request){
 		func(res http.ResponseWriter, req *http.Request) {
-			res.WriteHeader(200)
+			res.WriteHeader(http.StatusOK)
 			if _, err := res.Write([]byte("")); err != nil {
 				res.WriteHeader(http.StatusInternalServerError)
 				assert.Fail(t, "err: %v", err)
@@ -1005,7 +1005,7 @@ func TestSendCompressGzip(t *testing.T) {
 func TestSendCompressGzipDeprecated(t *testing.T) {
 	test := prepareSenderTest(t, "default", []func(res http.ResponseWriter, req *http.Request){
 		func(res http.ResponseWriter, req *http.Request) {
-			res.WriteHeader(200)
+			res.WriteHeader(http.StatusOK)
 			if _, err := res.Write([]byte("")); err != nil {
 				res.WriteHeader(http.StatusInternalServerError)
 				assert.Fail(t, "err: %v", err)
@@ -1026,7 +1026,7 @@ func TestSendCompressGzipDeprecated(t *testing.T) {
 func TestSendCompressZstd(t *testing.T) {
 	test := prepareSenderTest(t, configcompression.TypeZstd, []func(res http.ResponseWriter, req *http.Request){
 		func(res http.ResponseWriter, req *http.Request) {
-			res.WriteHeader(200)
+			res.WriteHeader(http.StatusOK)
 			if _, err := res.Write([]byte("")); err != nil {
 				res.WriteHeader(http.StatusInternalServerError)
 				assert.Fail(t, "err: %v", err)
@@ -1047,7 +1047,7 @@ func TestSendCompressZstd(t *testing.T) {
 func TestSendCompressDeflate(t *testing.T) {
 	test := prepareSenderTest(t, configcompression.TypeDeflate, []func(res http.ResponseWriter, req *http.Request){
 		func(res http.ResponseWriter, req *http.Request) {
-			res.WriteHeader(200)
+			res.WriteHeader(http.StatusOK)
 			if _, err := res.Write([]byte("")); err != nil {
 				res.WriteHeader(http.StatusInternalServerError)
 				assert.Fail(t, "err: %v", err)
@@ -1240,7 +1240,7 @@ func TestSendMetricsSplitFailedAll(t *testing.T) {
 			assert.Equal(t, expected, body)
 		},
 		func(w http.ResponseWriter, req *http.Request) {
-			w.WriteHeader(404)
+			w.WriteHeader(http.StatusNotFound)
 
 			body := extractBody(t, req)
 			expected := `` +

exporter/zipkinexporter/zipkin_test.go

@@ -175,7 +175,7 @@ func (r *mockZipkinReporter) Flush() error {
 		return err
 	}
 
-	req, err := http.NewRequest("POST", r.url, bytes.NewReader(body))
+	req, err := http.NewRequest(http.MethodPost, r.url, bytes.NewReader(body))
 	if err != nil {
 		return err
 	}

extension/headerssetterextension/extension_test.go

@@ -39,7 +39,7 @@ func TestRoundTripper(t *testing.T) {
 					Metadata: tt.metadata,
 				},
 			)
-			req, err := http.NewRequestWithContext(ctx, "GET", "", nil)
+			req, err := http.NewRequestWithContext(ctx, http.MethodGet, "", nil)
 			assert.NoError(t, err)
 			assert.NotNil(t, req)
 

extension/oauth2clientauthextension/extension_test.go

@@ -273,7 +273,7 @@ func TestOAuth2PerRPCCredentials(t *testing.T) {
 
 func TestFailContactingOAuth(t *testing.T) {
 	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
-		w.WriteHeader(200)
+		w.WriteHeader(http.StatusOK)
 		_, err := w.Write([]byte("not-json"))
 		assert.NoError(t, err)
 	}))
@@ -306,7 +306,7 @@ func TestFailContactingOAuth(t *testing.T) {
 		Transport: roundTripper,
 	}
 
-	req, err := http.NewRequest("POST", "http://example.com/", nil)
+	req, err := http.NewRequest(http.MethodPost, "http://example.com/", nil)
 	require.NoError(t, err)
 	_, err = client.Do(req)
 	assert.ErrorIs(t, err, errFailedToGetSecurityToken)

extension/opampextension/auth.go

@@ -61,7 +61,7 @@ func makeHeadersFunc(logger *zap.Logger, serverCfg *OpAMPServer, host component.
 		// This is a workaround while websocket authentication is being worked on.
 		// Currently, we are waiting on the auth module to be stabilized.
 		// See for more info: https://github.com/open-telemetry/opentelemetry-collector/issues/10864
-		dummyReq, err := http.NewRequest("GET", "http://example.com", nil)
+		dummyReq, err := http.NewRequest(http.MethodGet, "http://example.com", nil)
 		if err != nil {
 			logger.Error("Failed to create dummy request for authentication.", zap.Error(err))
 			return h

extension/sigv4authextension/extension_test.go

@@ -103,10 +103,10 @@ func TestGetCredsProviderFromConfig(t *testing.T) {
 }
 
 func TestCloneRequest(t *testing.T) {
-	req1, err := http.NewRequest("GET", "https://example.com", nil)
+	req1, err := http.NewRequest(http.MethodGet, "https://example.com", nil)
 	assert.NoError(t, err)
 
-	req2, err := http.NewRequest("GET", "https://example.com", nil)
+	req2, err := http.NewRequest(http.MethodGet, "https://example.com", nil)
 	assert.NoError(t, err)
 	req2.Header.Add("Header1", "val1")
 

extension/sigv4authextension/signingroundtripper_test.go

@@ -69,7 +69,7 @@ func TestRoundTrip(t *testing.T) {
 				assert.NoError(t, err)
 				assert.Equal(t, body, string(content))
 
-				w.WriteHeader(200)
+				w.WriteHeader(http.StatusOK)
 			}))
 			defer server.Close()
 			serverURL, _ := url.Parse(server.URL)
@@ -79,7 +79,7 @@ func TestRoundTrip(t *testing.T) {
 			assert.NoError(t, err)
 
 			newBody := strings.NewReader(body)
-			req, err := http.NewRequest("POST", serverURL.String(), newBody)
+			req, err := http.NewRequest(http.MethodPost, serverURL.String(), newBody)
 			assert.NoError(t, err)
 
 			res, err := rt.RoundTrip(req)
@@ -95,19 +95,19 @@ func TestRoundTrip(t *testing.T) {
 }
 
 func TestInferServiceAndRegion(t *testing.T) {
-	req1, err := http.NewRequest("GET", "https://example.com", nil)
+	req1, err := http.NewRequest(http.MethodGet, "https://example.com", nil)
 	assert.NoError(t, err)
 
-	req2, err := http.NewRequest("GET", "https://aps-workspaces.us-east-1.amazonaws.com/workspaces/ws-XXX/api/v1/remote_write", nil)
+	req2, err := http.NewRequest(http.MethodGet, "https://aps-workspaces.us-east-1.amazonaws.com/workspaces/ws-XXX/api/v1/remote_write", nil)
 	assert.NoError(t, err)
 
-	req3, err := http.NewRequest("GET", "https://search-my-domain.us-east-1.es.amazonaws.com/_search?q=house", nil)
+	req3, err := http.NewRequest(http.MethodGet, "https://search-my-domain.us-east-1.es.amazonaws.com/_search?q=house", nil)
 	assert.NoError(t, err)
 
-	req4, err := http.NewRequest("GET", "https://example.com", nil)
+	req4, err := http.NewRequest(http.MethodGet, "https://example.com", nil)
 	assert.NoError(t, err)
 
-	req5, err := http.NewRequest("GET", "https://aps-workspaces.us-east-1.amazonaws.com/workspaces/ws-XXX/api/v1/remote_write", nil)
+	req5, err := http.NewRequest(http.MethodGet, "https://aps-workspaces.us-east-1.amazonaws.com/workspaces/ws-XXX/api/v1/remote_write", nil)
 	assert.NoError(t, err)
 
 	tests := []struct {
@@ -172,13 +172,13 @@ func TestInferServiceAndRegion(t *testing.T) {
 }
 
 func TestHashPayload(t *testing.T) {
-	req1, err := http.NewRequest("GET", "https://example.com", nil)
+	req1, err := http.NewRequest(http.MethodGet, "https://example.com", nil)
 	assert.NoError(t, err)
 
-	req2, err := http.NewRequest("GET", "https://example.com", bytes.NewReader([]byte("This is a test.")))
+	req2, err := http.NewRequest(http.MethodGet, "https://example.com", bytes.NewReader([]byte("This is a test.")))
 	assert.NoError(t, err)
 
-	req3, err := http.NewRequest("GET", "https://example.com", nil)
+	req3, err := http.NewRequest(http.MethodGet, "https://example.com", nil)
 	assert.NoError(t, err)
 	req3.GetBody = func() (io.ReadCloser, error) { return nil, errors.New("this will always fail") }