From 1196d67b47f1862ddf60010c685e066d1fe40c86 Mon Sep 17 00:00:00 2001
From: Roma Sokolov <sokolov.r.v@gmail.com>
Date: Mon, 1 Feb 2016 16:55:14 +0000
Subject: [PATCH] Add LogrusLogger interface for Entry and Logger

This make it possible for client code to accept either Logger or Entry.
For example, utility function may accept logger object to inform fatal
errors and it is job of the calling code to provide either generic
top-level logger, or request-bound Entry created using .WithFields.

(fixes #308)
---
 logrus.go      | 36 ++++++++++++++++++++++++++++++++++++
 logrus_test.go | 17 +++++++++++++++++
 2 files changed, 53 insertions(+)

diff --git a/logrus.go b/logrus.go
index 0c09fbc..aa5fa7e 100644
--- a/logrus.go
+++ b/logrus.go
@@ -96,3 +96,39 @@ type StdLogger interface {
 	Panicf(string, ...interface{})
 	Panicln(...interface{})
 }
+
+// Logrus logger interface generalizes Entry and Logger types, so you can take any of these
+type LogrusLogger interface {
+	// we can return LogrusLogger here, but this will require many changes and will
+	// possible break backward compatiblity
+	WithField(key string, value interface{}) *Entry
+	WithFields(fields Fields) *Entry
+	WithError(err error) *Entry
+
+	Debugf(format string, args ...interface{})
+	Infof(format string, args ...interface{})
+	Printf(format string, args ...interface{})
+	Warnf(format string, args ...interface{})
+	Warningf(format string, args ...interface{})
+	Errorf(format string, args ...interface{})
+	Fatalf(format string, args ...interface{})
+	Panicf(format string, args ...interface{})
+
+	Debug(args ...interface{})
+	Info(args ...interface{})
+	Print(args ...interface{})
+	Warn(args ...interface{})
+	Warning(args ...interface{})
+	Error(args ...interface{})
+	Fatal(args ...interface{})
+	Panic(args ...interface{})
+
+	Debugln(args ...interface{})
+	Infoln(args ...interface{})
+	Println(args ...interface{})
+	Warnln(args ...interface{})
+	Warningln(args ...interface{})
+	Errorln(args ...interface{})
+	Fatalln(args ...interface{})
+	Panicln(args ...interface{})
+}
diff --git a/logrus_test.go b/logrus_test.go
index b7d9302..4bc1268 100644
--- a/logrus_test.go
+++ b/logrus_test.go
@@ -314,3 +314,20 @@ func TestLoggingRace(t *testing.T) {
 	}
 	wg.Wait()
 }
+
+// Compile test
+func TestLogrusInterface(t *testing.T) {
+	var buffer bytes.Buffer
+	fn := func(l LogrusLogger) {
+		b := l.WithField("key", "value")
+		b.Debug("Test")
+	}
+	// test logger
+	logger := New()
+	logger.Out = &buffer
+	fn(logger)
+
+	// test Entry
+	e := logger.WithField("another", "value")
+	fn(e)
+}