Fix issue with multiple/duplicate log entries during tests (#2906)

internal/log.go

@@ -33,6 +33,11 @@ import (
 	"github.com/matrix-org/dendrite/setup/config"
 )
 
+// logrus is using a global variable when we're using `logrus.AddHook`
+// this unfortunately results in us adding the same hook multiple times.
+// This map ensures we only ever add one level hook.
+var stdLevelLogAdded = make(map[logrus.Level]bool)
+
 type utcFormatter struct {
 	logrus.Formatter
 }

internal/log_unix.go

@@ -22,16 +22,16 @@ import (
 	"log/syslog"
 
 	"github.com/MFAshby/stdemuxerhook"
-	"github.com/matrix-org/dendrite/setup/config"
 	"github.com/sirupsen/logrus"
 	lSyslog "github.com/sirupsen/logrus/hooks/syslog"
+
+	"github.com/matrix-org/dendrite/setup/config"
 )
 
 // SetupHookLogging configures the logging hooks defined in the configuration.
 // If something fails here it means that the logging was improperly configured,
 // so we just exit with the error
 func SetupHookLogging(hooks []config.LogrusHook, componentName string) {
-	stdLogAdded := false
 	for _, hook := range hooks {
 		// Check we received a proper logging level
 		level, err := logrus.ParseLevel(hook.Level)
@@ -54,14 +54,11 @@ func SetupHookLogging(hooks []config.LogrusHook, componentName string) {
 			setupSyslogHook(hook, level, componentName)
 		case "std":
 			setupStdLogHook(level)
-			stdLogAdded = true
 		default:
 			logrus.Fatalf("Unrecognised logging hook type: %s", hook.Type)
 		}
 	}
-	if !stdLogAdded {
-		setupStdLogHook(logrus.InfoLevel)
-	}
+	setupStdLogHook(logrus.InfoLevel)
 	// Hooks are now configured for stdout/err, so throw away the default logger output
 	logrus.SetOutput(io.Discard)
 }
@@ -88,7 +85,11 @@ func checkSyslogHookParams(params map[string]interface{}) {
 }
 
 func setupStdLogHook(level logrus.Level) {
+	if stdLevelLogAdded[level] {
+		return
+	}
 	logrus.AddHook(&logLevelHook{level, stdemuxerhook.New(logrus.StandardLogger())})
+	stdLevelLogAdded[level] = true
 }
 
 func setupSyslogHook(hook config.LogrusHook, level logrus.Level, componentName string) {