add fields to log.print() (#360)

pkg/log/log.go

@@ -48,8 +48,8 @@ func Debug() Logger {
 }
 
 // Print adds `msg` to the log at `InfoLevel`. It is a wrapper for `Info().Print(msg)`, since this is the most common use case.
-func Print(msg string) {
-	Info().Print(msg)
+func Print(msg string, fields ...field.M) {
+	Info().Print(msg, fields...)
 }
 
 func WithContext(ctx context.Context) Logger {
@@ -60,13 +60,20 @@ func WithError(err error) Logger {
 	return Info().WithError(err)
 }
 
-func (l *logger) Print(msg string) {
+func (l *logger) Print(msg string, fields ...field.M) {
 	logFields := make(logrus.Fields)
 	if ctxFields := field.FromContext(l.ctx); ctxFields != nil {
 		for _, cf := range ctxFields.Fields() {
 			logFields[cf.Key()] = cf.Value()
 		}
 	}
+
+	for _, f := range fields {
+		for k, v := range f {
+			logFields[k] = v
+		}
+	}
+
 	entry := log.WithFields(logFields)
 	if l.err != nil {
 		entry = entry.WithError(l.err)

pkg/log/log_test.go

@@ -44,6 +44,16 @@ func (s *LogSuite) TestLogMessage(c *C) {
 	testLogMessage(c, text, Print)
 }
 
+func (s *LogSuite) TestLogWithFields(c *C) {
+	const text = "Some useful text."
+	entry := testLogMessage(c, text, Print, field.M{"key": "value"})
+	c.Assert(entry["level"], Equals, infoLevelStr)
+	// Error should not be set in the log entry
+	c.Assert(entry["error"], Equals, nil)
+	// A field with "key" should be set in the log entry
+	c.Assert(entry["key"], Equals, "value")
+}
+
 func (s *LogSuite) TestLogWithError(c *C) {
 	const text = "My error message"
 	err := errors.New("test error")
@@ -84,11 +94,11 @@ func (s *LogSuite) TestLogWithContextFieldsAndError(c *C) {
 	c.Assert(entry["key"], Equals, "value")
 }
 
-func testLogMessage(c *C, msg string, print func(string)) map[string]interface{} {
+func testLogMessage(c *C, msg string, print func(string, ...field.M), fields ...field.M) map[string]interface{} {
 	log.SetFormatter(&logrus.JSONFormatter{TimestampFormat: time.RFC3339Nano})
 	var memLog bytes.Buffer
 	log.SetOutput(&memLog)
-	print(msg)
+	print(msg, fields...)
 	var entry map[string]interface{}
 	err := json.Unmarshal(memLog.Bytes(), &entry)
 	c.Assert(err, IsNil)

pkg/log/logger.go

@@ -2,10 +2,12 @@ package log
 
 import (
 	"context"
+
+	"github.com/kanisterio/kanister/pkg/field"
 )
 
 type Logger interface {
-	Print(msg string)
+	Print(msg string, fields ...field.M)
 	WithContext(ctx context.Context) Logger
 	WithError(err error) Logger
 }