From 7d3ddc68a3c3aa2184059ed57648b0d1e18351c0 Mon Sep 17 00:00:00 2001
From: Ernesto Alejo <ernestokarim@gmail.com>
Date: Wed, 6 Sep 2017 19:34:58 +0200
Subject: [PATCH] Split terminal check to add build tags to support App Engine.

---
 terminal_check_appengine.go    | 11 +++++++++++
 terminal_check_notappengine.go | 19 +++++++++++++++++++
 text_formatter.go              | 15 +--------------
 3 files changed, 31 insertions(+), 14 deletions(-)
 create mode 100644 terminal_check_appengine.go
 create mode 100644 terminal_check_notappengine.go

diff --git a/terminal_check_appengine.go b/terminal_check_appengine.go
new file mode 100644
index 0000000..2403de9
--- /dev/null
+++ b/terminal_check_appengine.go
@@ -0,0 +1,11 @@
+// +build appengine
+
+package logrus
+
+import (
+	"io"
+)
+
+func checkIfTerminal(w io.Writer) bool {
+	return true
+}
diff --git a/terminal_check_notappengine.go b/terminal_check_notappengine.go
new file mode 100644
index 0000000..116bcb4
--- /dev/null
+++ b/terminal_check_notappengine.go
@@ -0,0 +1,19 @@
+// +build !appengine
+
+package logrus
+
+import (
+	"io"
+	"os"
+
+	"golang.org/x/crypto/ssh/terminal"
+)
+
+func checkIfTerminal(w io.Writer) bool {
+	switch v := w.(type) {
+	case *os.File:
+		return terminal.IsTerminal(int(v.Fd()))
+	default:
+		return false
+	}
+}
diff --git a/text_formatter.go b/text_formatter.go
index be412aa..61b21ca 100644
--- a/text_formatter.go
+++ b/text_formatter.go
@@ -3,14 +3,10 @@ package logrus
 import (
 	"bytes"
 	"fmt"
-	"io"
-	"os"
 	"sort"
 	"strings"
 	"sync"
 	"time"
-
-	"golang.org/x/crypto/ssh/terminal"
 )
 
 const (
@@ -65,16 +61,7 @@ type TextFormatter struct {
 
 func (f *TextFormatter) init(entry *Entry) {
 	if entry.Logger != nil {
-		f.isTerminal = f.checkIfTerminal(entry.Logger.Out)
-	}
-}
-
-func (f *TextFormatter) checkIfTerminal(w io.Writer) bool {
-	switch v := w.(type) {
-	case *os.File:
-		return terminal.IsTerminal(int(v.Fd()))
-	default:
-		return false
+		f.isTerminal = checkIfTerminal(entry.Logger.Out)
 	}
 }