Merge pull request #27 from lefinal/feat-add-error-message-omit

feat(mehlog): add option to omit error message field

mehlog/mehlog.go

@@ -8,6 +8,18 @@ import (
 	"sync"
 )
 
+var omitErrorMessageField = false
+var omitErrorMessageFieldMutex sync.RWMutex
+
+// OmitErrorMessageField sets whether the error message field with key
+// meh.MapFieldErrorMessage should be omitted in logs and only output as log
+// message in order to improve human readability.
+func OmitErrorMessageField(omit bool) {
+	omitErrorMessageFieldMutex.Lock()
+	defer omitErrorMessageFieldMutex.Unlock()
+	omitErrorMessageField = omit
+}
+
 var (
 	// defaultLevelTranslator is the default LevelTranslator that translates every
 	// meh.Code to zapcore.ErrorLevel.
@@ -48,17 +60,23 @@ func Log(logger *zap.Logger, err error) {
 func LogToLevel(logger *zap.Logger, level zapcore.Level, err error) {
 	e := meh.Cast(err)
 	// Build fields.
+	omitErrorMessageFieldMutex.RLock()
+	omitErrorMessageField := omitErrorMessageField
+	omitErrorMessageFieldMutex.RUnlock()
 	fieldMap := meh.ToMap(e)
 	fields := make([]zap.Field, 0, len(fieldMap))
 	for k, v := range fieldMap {
+		if omitErrorMessageField && k == meh.MapFieldErrorMessage {
+			continue
+		}
 		fields = append(fields, zap.Any(k, v))
 	}
 	// Log it.
 	logToLevel(logger, level, e.Error(), fields...)
 }
 
 // logToLevel calls the correct LogToLevel method for the given zap.Logger based on the
-// zapcore.level.
+// zapcore.Level.
 func logToLevel(logger *zap.Logger, level zapcore.Level, message string, fields ...zapcore.Field) {
 	switch level {
 	case zapcore.DebugLevel:

mehlog/mehlog_test.go

@@ -78,6 +78,44 @@ func (suite *LogSuite) TestErrorMessage() {
 	suite.Equal(e.Error(), records[0].Entry.Message, "should use error message as message")
 }
 
+// TestOmitErrorMessageField assures that the error message field is not logged
+// if omitted.
+func (suite *LogSuite) TestOmitErrorMessageField() {
+	oldOmitted := omitErrorMessageField
+	OmitErrorMessageField(true)
+	defer OmitErrorMessageField(oldOmitted)
+	logger, rec := zaprec.NewRecorder(nil)
+	e := meh.Wrap(&meh.Error{Message: "inner"}, "outer", nil)
+	Log(logger, e)
+	records := rec.Records()
+	suite.Require().Len(records, 1, "should have been logged")
+	suite.Equal(e.Error(), records[0].Entry.Message, "should use error message as message")
+	fieldNames := make([]string, 0)
+	for _, field := range records[0].Fields {
+		fieldNames = append(fieldNames, field.Key)
+	}
+	suite.NotContains(fieldNames, meh.MapFieldErrorMessage, "should not contain error message")
+}
+
+// TestIncludeErrorMessageField assures that the error message field is logged if
+// not omitted.
+func (suite *LogSuite) TestIncludeErrorMessageField() {
+	oldOmitted := omitErrorMessageField
+	OmitErrorMessageField(false)
+	defer OmitErrorMessageField(oldOmitted)
+	logger, rec := zaprec.NewRecorder(nil)
+	e := meh.Wrap(&meh.Error{Message: "inner"}, "outer", nil)
+	Log(logger, e)
+	records := rec.Records()
+	suite.Require().Len(records, 1, "should have been logged")
+	suite.Equal(e.Error(), records[0].Entry.Message, "should use error message as message")
+	fieldNames := make([]string, 0)
+	for _, field := range records[0].Fields {
+		fieldNames = append(fieldNames, field.Key)
+	}
+	suite.Contains(fieldNames, meh.MapFieldErrorMessage, "should not contain error message")
+}
+
 func TestLog(t *testing.T) {
 	suite.Run(t, new(LogSuite))
 }
@@ -99,7 +137,7 @@ type logToLevelSuite struct {
 
 // expect a logToLevel call with the given in-level to log an entry with given
 // out-level.
-func (suite logToLevelSuite) expect(levelIn zapcore.Level, levelOut zapcore.Level) {
+func (suite *logToLevelSuite) expect(levelIn zapcore.Level, levelOut zapcore.Level) {
 	logger, rec := zaprec.NewRecorder(nil)
 	logToLevel(logger, levelIn, "meow")
 	suite.Len(rec.Records(), 1, "should have been logged")