From 2457ebf2dd1e3e54073b469cc19fb33615b1cea4 Mon Sep 17 00:00:00 2001
From: Ben Kochie <superq@gmail.com>
Date: Sun, 29 Nov 2020 16:48:18 +0100
Subject: [PATCH] Capture newlines in log stdlib

Capture newlines in the stdlib adapter messages. Avoids cutting off
multi-line log messages.

See: https://github.com/prometheus/node_exporter/issues/1886

Signed-off-by: Ben Kochie <superq@gmail.com>
---
 log/stdlib.go      |  2 +-
 log/stdlib_test.go | 20 +++++++++++++-------
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/log/stdlib.go b/log/stdlib.go
index 2d030c456..2d2e9c060 100644
--- a/log/stdlib.go
+++ b/log/stdlib.go
@@ -131,7 +131,7 @@ const (
 	logRegexpDate = `(?P<date>[0-9]{4}/[0-9]{2}/[0-9]{2})?[ ]?`
 	logRegexpTime = `(?P<time>[0-9]{2}:[0-9]{2}:[0-9]{2}(\.[0-9]+)?)?[ ]?`
 	logRegexpFile = `(?P<file>.+?:[0-9]+)?`
-	logRegexpMsg  = `(: )?(?P<msg>.*)`
+	logRegexpMsg  = `(: )?(?P<msg>(?s:.*))`
 )
 
 var (
diff --git a/log/stdlib_test.go b/log/stdlib_test.go
index ae9d82ce4..2a119c6ef 100644
--- a/log/stdlib_test.go
+++ b/log/stdlib_test.go
@@ -31,13 +31,13 @@ func TestStdlibAdapterUsage(t *testing.T) {
 	time := now.Format("15:04:05")
 
 	for flag, want := range map[int]string{
-		0:                                      "msg=hello\n",
-		log.Ldate:                              "ts=" + date + " msg=hello\n",
-		log.Ltime:                              "ts=" + time + " msg=hello\n",
-		log.Ldate | log.Ltime:                  "ts=\"" + date + " " + time + "\" msg=hello\n",
-		log.Lshortfile:                         "caller=stdlib_test.go:44 msg=hello\n",
-		log.Lshortfile | log.Ldate:             "ts=" + date + " caller=stdlib_test.go:44 msg=hello\n",
-		log.Lshortfile | log.Ldate | log.Ltime: "ts=\"" + date + " " + time + "\" caller=stdlib_test.go:44 msg=hello\n",
+		0:                                      "msg=\"hello\\n\"\n",
+		log.Ldate:                              "ts=" + date + " msg=\"hello\\n\"\n",
+		log.Ltime:                              "ts=" + time + " msg=\"hello\\n\"\n",
+		log.Ldate | log.Ltime:                  "ts=\"" + date + " " + time + "\" msg=\"hello\\n\"\n",
+		log.Lshortfile:                         "caller=stdlib_test.go:44 msg=\"hello\\n\"\n",
+		log.Lshortfile | log.Ldate:             "ts=" + date + " caller=stdlib_test.go:44 msg=\"hello\\n\"\n",
+		log.Lshortfile | log.Ldate | log.Ltime: "ts=\"" + date + " " + time + "\" caller=stdlib_test.go:44 msg=\"hello\\n\"\n",
 	} {
 		buf.Reset()
 		stdlog.SetFlags(flag)
@@ -130,6 +130,12 @@ func TestStdlibAdapterSubexps(t *testing.T) {
 			"file": "",
 			"msg":  "hello world",
 		},
+		"hello\nworld": {
+			"date": "",
+			"time": "",
+			"file": "",
+			"msg":  "hello\nworld",
+		},
 		"2009/01/23: hello world": {
 			"date": "2009/01/23",
 			"time": "",