lint: errcheck (#3912)

Author: mmetc

.golangci.yml

@@ -119,8 +119,6 @@ linters:
       # See https://github.com/kisielk/errcheck#excluding-functions for details.
       exclude-functions:
         - (*bytes.Buffer).ReadFrom          # TODO
-        - (net/http.ResponseWriter).Write   # TODO
-        - (*os/exec.Cmd).Wait
         - syscall.FreeLibrary
         - golang.org/x/sys/windows.CloseHandle
         - golang.org/x/sys/windows.ResetEvent

cmd/crowdsec-cli/clinotifications/notifications.go

@@ -360,7 +360,7 @@ func (cli *cliNotifications) newTestCmd() *cobra.Command {
 
 			// time.Sleep(2 * time.Second) // There's no mechanism to ensure notification has been sent
 			pluginTomb.Kill(errors.New("terminating"))
-			pluginTomb.Wait()
+			_ = pluginTomb.Wait()
 
 			return nil
 		},
@@ -478,7 +478,7 @@ cscli notifications reinject <alert_id> -a '{"remediation": true,"scenario":"not
 			}
 			// time.Sleep(2 * time.Second) // There's no mechanism to ensure notification has been sent
 			pluginTomb.Kill(errors.New("terminating"))
-			pluginTomb.Wait()
+			_ = pluginTomb.Wait()
 
 			return nil
 		},

pkg/acquisition/modules/file/file_test.go

@@ -595,7 +595,7 @@ mode: tail
 
 	// Cleanup
 	tomb.Kill(nil)
-	tomb.Wait()
+	require.NoError(t, tomb.Wait())
 }
 
 func TestFileResurrectionViaPolling(t *testing.T) {
@@ -645,5 +645,5 @@ mode: tail
 
 	// Cleanup
 	tomb.Kill(nil)
-	tomb.Wait()
+	require.NoError(t, tomb.Wait())
 }

pkg/acquisition/modules/http/http.go

@@ -174,11 +174,11 @@ func (h *HTTPSource) GetMode() string {
 	return h.Config.Mode
 }
 
-func (h *HTTPSource) GetName() string {
+func (*HTTPSource) GetName() string {
 	return dataSourceName
 }
 
-func (h *HTTPSource) CanRun() error {
+func (*HTTPSource) CanRun() error {
 	return nil
 }
 
@@ -269,6 +269,7 @@ func (h *HTTPSource) processRequest(w http.ResponseWriter, r *http.Request, hc *
 
 	if h.logger.Logger.IsLevelEnabled(log.TraceLevel) {
 		h.logger.Tracef("processing request from '%s' with method '%s' and path '%s'", r.RemoteAddr, r.Method, r.URL.Path)
+
 		bodyContent, err := httputil.DumpRequest(r, true)
 		if err != nil {
 			h.logger.Errorf("failed to dump request: %s", err)
@@ -350,7 +351,11 @@ func (h *HTTPSource) RunServer(ctx context.Context, out chan types.Event, t *tom
 		case http.MethodGet, http.MethodHead: // Return a 200 if the auth was successful
 			h.logger.Infof("successful %s request from '%s'", r.Method, r.RemoteAddr)
 			w.WriteHeader(http.StatusOK)
-			w.Write([]byte("OK"))
+
+			if _, err := w.Write([]byte("OK")); err != nil {
+				h.logger.Errorf("failed to write response: %v", err)
+			}
+
 			return
 		case http.MethodPost: // POST is handled below
 		default:
@@ -382,7 +387,9 @@ func (h *HTTPSource) RunServer(ctx context.Context, out chan types.Event, t *tom
 			w.WriteHeader(http.StatusOK)
 		}
 
-		w.Write([]byte("OK"))
+		if _, err := w.Write([]byte("OK")); err != nil {
+			h.logger.Errorf("failed to write response: %v", err)
+		}
 	})
 
 	h.Server = &http.Server{
@@ -417,12 +424,15 @@ func (h *HTTPSource) RunServer(ctx context.Context, out chan types.Event, t *tom
 		}
 
 		defer trace.CatchPanic("crowdsec/acquis/http/server/unix")
+
 		h.logger.Infof("creating unix socket on %s", h.Config.ListenSocket)
 		_ = os.Remove(h.Config.ListenSocket)
+
 		listener, err := listenConfig.Listen(ctx, "unix", h.Config.ListenSocket)
 		if err != nil {
 			return csnet.WrapSockErr(err, h.Config.ListenSocket)
 		}
+
 		if h.Config.TLS != nil {
 			err := h.Server.ServeTLS(listener, h.Config.TLS.ServerCert, h.Config.TLS.ServerKey)
 			if err != nil && err != http.ErrServerClosed {

pkg/acquisition/modules/journalctl/journalctl.go

@@ -99,15 +99,15 @@ func (j *JournalCtlSource) runJournalCtl(ctx context.Context, out chan types.Eve
 
 	if stdoutscanner == nil {
 		cancel()
-		cmd.Wait()
+		_ = cmd.Wait()
 		return errors.New("failed to create stdout scanner")
 	}
 
 	stderrScanner := bufio.NewScanner(stderr)
 
 	if stderrScanner == nil {
 		cancel()
-		cmd.Wait()
+		_ = cmd.Wait()
 		return errors.New("failed to create stderr scanner")
 	}
 
@@ -125,7 +125,10 @@ func (j *JournalCtlSource) runJournalCtl(ctx context.Context, out chan types.Eve
 		case <-t.Dying():
 			logger.Infof("journalctl datasource %s stopping", j.src)
 			cancel()
-			cmd.Wait() // avoid zombie process
+			// avoid zombie process
+			if waitErr := cmd.Wait(); waitErr != nil {
+				j.logger.Debugf("journalctl exited after cancel: %v", waitErr)
+			}
 
 			return nil
 		case stdoutLine := <-stdoutChan: