From 7086de352ad27148f766e47535e7c18a82b5d564 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Maxime=20Soul=C3=A9?= <btik-git@scoubidou.com>
Date: Sat, 10 Feb 2018 18:44:57 +0100
Subject: [PATCH] Logrus format: displayed level correctly matches
 graylog/syslog one
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following gemnasium/logrus-graylog-hook@4dad8bd

Signed-off-by: Maxime Soulé <btik-git@scoubidou.com>
---
 format.go      | 27 +++++++++++++++----
 format_test.go | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 95 insertions(+), 5 deletions(-)
 create mode 100644 format_test.go

diff --git a/format.go b/format.go
index 11c1d05..cf970af 100644
--- a/format.go
+++ b/format.go
@@ -24,13 +24,30 @@ var supportedFormat = func() []string {
 	return a
 }()
 
-// From https://github.com/gemnasium/logrus-graylog-hook/blob/master/graylog_hook.go#L166
-func logrusLevelToString(v int) string {
-	return logrus.Level(v - 2).String()
+var syslogLevelToLogrus = [...]string{
+	strings.ToUpper(logrus.PanicLevel.String())[:4], // LOG_EMERG   = 0
+	strings.ToUpper(logrus.PanicLevel.String())[:4], // LOG_ALERT   = 1
+	strings.ToUpper(logrus.FatalLevel.String())[:4], // LOG_CRIT    = 2
+	strings.ToUpper(logrus.ErrorLevel.String())[:4], // LOG_ERR     = 3
+	strings.ToUpper(logrus.WarnLevel.String())[:4],  // LOG_WARNING = 4
+	strings.ToUpper(logrus.InfoLevel.String())[:4],  // LOG_NOTICE  = 5
+	strings.ToUpper(logrus.InfoLevel.String())[:4],  // LOG_INFO    = 6
+	strings.ToUpper(logrus.DebugLevel.String())[:4], // LOG_DEBUG   = 7
+}
+
+// String reverse of
+// https://github.com/gemnasium/logrus-graylog-hook/blob/master/graylog_hook.go#L144
+func syslogLevelToLogrusString(v int) string {
+	if v < 0 {
+		v = 0
+	} else if v >= len(syslogLevelToLogrus) {
+		v = len(syslogLevelToLogrus) - 1
+	}
+	return syslogLevelToLogrus[v]
 }
 
 func logrusFormater(v map[string]interface{}) string {
-	level := logrusLevelToString(int(v["level"].(float64)))
+	level := syslogLevelToLogrusString(int(v["level"].(float64)))
 	timestamp := int64(v["timestamp"].(float64))
 
 	// Fields
@@ -44,7 +61,7 @@ func logrusFormater(v map[string]interface{}) string {
 
 	// Output
 	b := &bytes.Buffer{}
-	fmt.Fprintf(b, "%s[%s] %-44s", strings.ToUpper(level)[0:4], time.Unix(timestamp, 0).Format(time.RFC3339), v["short_message"])
+	fmt.Fprintf(b, "%s[%s] %-44s", level, time.Unix(timestamp, 0).Format(time.RFC3339), v["short_message"])
 
 	for _, k := range keys {
 		fmt.Fprintf(b, ` %s="%v"`, k[1:], v[k])
diff --git a/format_test.go b/format_test.go
new file mode 100644
index 0000000..e1c2c71
--- /dev/null
+++ b/format_test.go
@@ -0,0 +1,73 @@
+package main
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/sirupsen/logrus"
+)
+
+func TestFormat(t *testing.T) {
+	const (
+		LOG_EMERG   = 0
+		LOG_ALERT   = 1
+		LOG_CRIT    = 2
+		LOG_ERR     = 3
+		LOG_WARNING = 4
+		LOG_NOTICE  = 5
+		LOG_INFO    = 6
+		LOG_DEBUG   = 7
+	)
+
+	expected := strings.ToUpper(logrus.PanicLevel.String())[:4]
+	got := syslogLevelToLogrusString(LOG_EMERG)
+	if got != expected {
+		t.Errorf("LOG_EMERG: expected `%s', got `%s'", expected, got)
+	}
+	expected = strings.ToUpper(logrus.PanicLevel.String())[:4]
+	got = syslogLevelToLogrusString(LOG_ALERT)
+	if got != expected {
+		t.Errorf("LOG_ALERT: expected `%s', got `%s'", expected, got)
+	}
+	expected = strings.ToUpper(logrus.FatalLevel.String())[:4]
+	got = syslogLevelToLogrusString(LOG_CRIT)
+	if got != expected {
+		t.Errorf("LOG_CRIT: expected `%s', got `%s'", expected, got)
+	}
+	expected = strings.ToUpper(logrus.ErrorLevel.String())[:4]
+	got = syslogLevelToLogrusString(LOG_ERR)
+	if got != expected {
+		t.Errorf("LOG_ERR: expected `%s', got `%s'", expected, got)
+	}
+	expected = strings.ToUpper(logrus.WarnLevel.String())[:4]
+	got = syslogLevelToLogrusString(LOG_WARNING)
+	if got != expected {
+		t.Errorf("LOG_WARNING: expected `%s', got `%s'", expected, got)
+	}
+	expected = strings.ToUpper(logrus.InfoLevel.String())[:4]
+	got = syslogLevelToLogrusString(LOG_NOTICE)
+	if got != expected {
+		t.Errorf("LOG_NOTICE: expected `%s', got `%s'", expected, got)
+	}
+	expected = strings.ToUpper(logrus.InfoLevel.String())[:4]
+	got = syslogLevelToLogrusString(LOG_INFO)
+	if got != expected {
+		t.Errorf("LOG_INFO: expected `%s', got `%s'", expected, got)
+	}
+	expected = strings.ToUpper(logrus.DebugLevel.String())[:4]
+	got = syslogLevelToLogrusString(LOG_DEBUG)
+	if got != expected {
+		t.Errorf("LOG_DEBUG: expected `%s', got `%s'", expected, got)
+	}
+
+	expected = strings.ToUpper(logrus.PanicLevel.String())[:4]
+	got = syslogLevelToLogrusString(LOG_EMERG - 1)
+	if got != expected {
+		t.Errorf("<LOG_EMERG: expected `%s', got `%s'", expected, got)
+	}
+	expected = strings.ToUpper(logrus.DebugLevel.String())[:4]
+	got = syslogLevelToLogrusString(LOG_DEBUG + 1)
+	if got != expected {
+		t.Errorf(">LOG_DEBUG: expected `%s', got `%s'", expected, got)
+	}
+}