add ParseLevel to get Level from string

logrus.go

diff --git a/logrus.go b/logrus.go
index 79df39c..35c6d19 100644
--- a/logrus.go
+++ b/logrus.go
@@ -1,6 +1,7 @@
 package logrus
 
 import (
+	"fmt"
 	"log"
 )
 
@@ -30,6 +31,27 @@
 	return "unknown"
 }
 
+func ParseLevel(lvl string) (Level, error) {
+	switch lvl {
+	case "panic":
+		return PanicLevel, nil
+	case "fatal":
+		return FatalLevel, nil
+	case "error":
+		return ErrorLevel, nil
+	case "warn", "warning":
+		return WarnLevel, nil
+	case "info":
+		return InfoLevel, nil
+	case "debug", "dbg":
+		return DebugLevel, nil
+	}
+
+	var l Level
+	return l, fmt.Errorf("not a valid logrus Level: %q", lvl)
+
+}
+
 // These are the different logging levels. You can set the logging level to log
 // on your instance of logger, obtained with `logrus.New()`.
 const (

logrus_test.go

diff --git a/logrus_test.go b/logrus_test.go
index 6202300..e476838 100644
--- a/logrus_test.go
+++ b/logrus_test.go
@@ -171,3 +171,40 @@
 	assert.Equal(t, "fatal", FatalLevel.String())
 	assert.Equal(t, "panic", PanicLevel.String())
 }
+
+func TestParseLevel(t *testing.T) {
+	l, err := ParseLevel("panic")
+	assert.Nil(t, err)
+	assert.Equal(t, PanicLevel, l)
+
+	l, err = ParseLevel("fatal")
+	assert.Nil(t, err)
+	assert.Equal(t, FatalLevel, l)
+
+	l, err = ParseLevel("error")
+	assert.Nil(t, err)
+	assert.Equal(t, ErrorLevel, l)
+
+	l, err = ParseLevel("warn")
+	assert.Nil(t, err)
+	assert.Equal(t, WarnLevel, l)
+
+	l, err = ParseLevel("warning")
+	assert.Nil(t, err)
+	assert.Equal(t, WarnLevel, l)
+
+	l, err = ParseLevel("info")
+	assert.Nil(t, err)
+	assert.Equal(t, InfoLevel, l)
+
+	l, err = ParseLevel("debug")
+	assert.Nil(t, err)
+	assert.Equal(t, DebugLevel, l)
+
+	l, err = ParseLevel("dbg")
+	assert.Nil(t, err)
+	assert.Equal(t, DebugLevel, l)
+
+	l, err = ParseLevel("invalid")
+	assert.Equal(t, "not a valid logrus Level: \"invalid\"", err.Error())
+}