Adds IsOutputLevelEnabled to allow wasm to opt-out of generating strings (#24)

* Adds IsOutputLevelEnabled to allow wasm to opt-out of generating strings

Allocation of log messages is expensive in WebAssembly. This exposes the
underlying IsLevelEnabled as IsOutputLevelEnabled. This will allow
request-scoped caching of this and help wasm filters avoid overhead
created for no reason.

Signed-off-by: Adrian Cole <adrian@tetrate.io>

* lint

Signed-off-by: Adrian Cole <adrian@tetrate.io>

Signed-off-by: Adrian Cole <adrian@tetrate.io>

logger/dapr_logger.go

@@ -89,7 +89,7 @@ func (l *daprLogger) SetAppID(id string) {
 }
 
 func toLogrusLevel(lvl LogLevel) logrus.Level {
-	// ignore error because it will never happens
+	// ignore error because it will never happen
 	l, _ := logrus.ParseLevel(string(lvl))
 	return l
 }
@@ -99,6 +99,11 @@ func (l *daprLogger) SetOutputLevel(outputLevel LogLevel) {
 	l.logger.Logger.SetLevel(toLogrusLevel(outputLevel))
 }
 
+// IsOutputLevelEnabled returns true if the logger will output this LogLevel.
+func (l *daprLogger) IsOutputLevelEnabled(level LogLevel) bool {
+	return l.logger.Logger.IsLevelEnabled(toLogrusLevel(level))
+}
+
 // SetOutput sets the destination for the logs.
 func (l *daprLogger) SetOutput(dst io.Writer) {
 	l.logger.Logger.SetOutput(dst)

logger/dapr_logger_test.go

@@ -33,6 +33,7 @@ const fakeLoggerName = "fakeLogger"
 func getTestLogger(buf io.Writer) *daprLogger {
 	l := newDaprLogger(fakeLoggerName)
 	l.SetOutput(buf)
+	l.logger.Logger.ExitFunc = func(i int) {} // don't quit the test
 
 	return l
 }
@@ -164,6 +165,105 @@ func TestJSONLoggerFields(t *testing.T) {
 	}
 }
 
+func TestOutputLevel(t *testing.T) {
+	tests := []struct {
+		outputLevel          LogLevel
+		expectedOutputLevels map[LogLevel]bool
+	}{
+		{
+			outputLevel: DebugLevel,
+			expectedOutputLevels: map[LogLevel]bool{
+				DebugLevel: true,
+				InfoLevel:  true,
+				WarnLevel:  true,
+				ErrorLevel: true,
+				FatalLevel: true,
+			},
+		},
+		{
+			outputLevel: InfoLevel,
+			expectedOutputLevels: map[LogLevel]bool{
+				DebugLevel: false,
+				InfoLevel:  true,
+				WarnLevel:  true,
+				ErrorLevel: true,
+				FatalLevel: true,
+			},
+		},
+		{
+			outputLevel: WarnLevel,
+			expectedOutputLevels: map[LogLevel]bool{
+				DebugLevel: false,
+				InfoLevel:  false,
+				WarnLevel:  true,
+				ErrorLevel: true,
+				FatalLevel: true,
+			},
+		},
+		{
+			outputLevel: ErrorLevel,
+			expectedOutputLevels: map[LogLevel]bool{
+				DebugLevel: false,
+				InfoLevel:  false,
+				WarnLevel:  false,
+				ErrorLevel: true,
+				FatalLevel: true,
+			},
+		},
+		{
+			outputLevel: FatalLevel,
+			expectedOutputLevels: map[LogLevel]bool{
+				DebugLevel: false,
+				InfoLevel:  false,
+				WarnLevel:  false,
+				ErrorLevel: false,
+				FatalLevel: true,
+			},
+		},
+		{
+			outputLevel: UndefinedLevel,
+			expectedOutputLevels: map[LogLevel]bool{
+				DebugLevel: false,
+				InfoLevel:  false,
+				WarnLevel:  false,
+				ErrorLevel: false,
+				FatalLevel: false,
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(string(tt.outputLevel), func(t *testing.T) {
+			for l, want := range tt.expectedOutputLevels {
+				var buf bytes.Buffer
+				testLogger := getTestLogger(&buf)
+				testLogger.SetOutputLevel(tt.outputLevel)
+
+				assert.Equal(t, want, testLogger.IsOutputLevelEnabled(l))
+
+				switch l {
+				case DebugLevel:
+					testLogger.Debug("")
+				case InfoLevel:
+					testLogger.Info("")
+				case WarnLevel:
+					testLogger.Warn("")
+				case ErrorLevel:
+					testLogger.Error("")
+				case FatalLevel:
+					testLogger.Fatal("")
+				}
+
+				if want {
+					assert.NotEmptyf(t, buf.Bytes(), "expected to log %v", l)
+				} else {
+					assert.Emptyf(t, buf.Bytes(), "expected to not log %v", l)
+				}
+			}
+		})
+	}
+}
+
 func TestWithTypeFields(t *testing.T) {
 	var buf bytes.Buffer
 	testLogger := getTestLogger(&buf)

logger/logger.go

@@ -63,18 +63,22 @@ var (
 )
 
 // Logger includes the logging api sets.
-type Logger interface {
+type Logger interface { //nolint: interfacebloat
 	// EnableJSONOutput enables JSON formatted output log
 	EnableJSONOutput(enabled bool)
 
 	// SetAppID sets dapr_id field in the log. Default value is empty string
 	SetAppID(id string)
-	// SetOutputLevel sets log output level
+
+	// SetOutputLevel sets the log output level
 	SetOutputLevel(outputLevel LogLevel)
 	// SetOutput sets the destination for the logs
 	SetOutput(dst io.Writer)
 
-	// WithLogType specify the log_type field in log. Default value is LogTypeLog
+	// IsOutputLevelEnabled returns true if the logger will output this LogLevel.
+	IsOutputLevelEnabled(level LogLevel) bool
+
+	// WithLogType specifies the log_type field in log. Default value is LogTypeLog
 	WithLogType(logType string) Logger
 
 	// WithFields returns a logger with the added structured fields.