From 9fc9af69b40f9704fc3d888c5d0a93caa90a67b1 Mon Sep 17 00:00:00 2001
From: Jude DSouza <jude.dsouza@magine.com>
Date: Thu, 11 Apr 2019 18:04:28 +0200
Subject: [PATCH] Enforce log level filter for log files

---
 logger/logfile.go      | 11 +++++++++++
 logger/logfile_test.go | 24 +++++++++++++++++++++---
 logger/logger.go       |  2 +-
 3 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/logger/logfile.go b/logger/logfile.go
index d3ca4749dc..bf13c0955e 100644
--- a/logger/logfile.go
+++ b/logger/logfile.go
@@ -7,6 +7,8 @@ import (
 	"strings"
 	"sync"
 	"time"
+
+	"github.com/hashicorp/logutils"
 )
 
 var (
@@ -15,6 +17,9 @@ var (
 
 //LogFile is used to setup a file based logger that also performs log rotation
 type LogFile struct {
+	// Log level Filter to filter out logs that do not matcch LogLevel criteria
+	logFilter *logutils.LevelFilter
+
 	//Name of the log file
 	fileName string
 
@@ -76,7 +81,13 @@ func (l *LogFile) rotate() error {
 	return nil
 }
 
+// Write is used to implement io.Writer
 func (l *LogFile) Write(b []byte) (n int, err error) {
+	// Filter out log entries that do not match log level criteria
+	if !l.logFilter.Check(b) {
+		return 0, nil
+	}
+
 	l.acquire.Lock()
 	defer l.acquire.Unlock()
 	//Create a new file if we have no file to write to
diff --git a/logger/logfile_test.go b/logger/logfile_test.go
index 328ec70a70..3f13ac0488 100644
--- a/logger/logfile_test.go
+++ b/logger/logfile_test.go
@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"github.com/hashicorp/consul/sdk/testutil"
+	"github.com/hashicorp/logutils"
 )
 
 const (
@@ -19,7 +20,8 @@ func TestLogFile_timeRotation(t *testing.T) {
 	t.Parallel()
 	tempDir := testutil.TempDir(t, "LogWriterTime")
 	defer os.Remove(tempDir)
-	logFile := LogFile{fileName: testFileName, logPath: tempDir, duration: testDuration}
+	filt := LevelFilter()
+	logFile := LogFile{logFilter: filt, fileName: testFileName, logPath: tempDir, duration: testDuration}
 	logFile.Write([]byte("Hello World"))
 	time.Sleep(2 * time.Second)
 	logFile.Write([]byte("Second File"))
@@ -34,7 +36,6 @@ func TestLogFile_openNew(t *testing.T) {
 	tempDir := testutil.TempDir(t, "LogWriterOpen")
 	defer os.Remove(tempDir)
 	logFile := LogFile{fileName: testFileName, logPath: tempDir, duration: testDuration}
-
 	if err := logFile.openNew(); err != nil {
 		t.Errorf("Expected open file %s, got an error (%s)", testFileName, err)
 	}
@@ -48,7 +49,9 @@ func TestLogFile_byteRotation(t *testing.T) {
 	t.Parallel()
 	tempDir := testutil.TempDir(t, "LogWriterBytes")
 	defer os.Remove(tempDir)
-	logFile := LogFile{fileName: testFileName, logPath: tempDir, MaxBytes: testBytes, duration: 24 * time.Hour}
+	filt := LevelFilter()
+	filt.MinLevel = logutils.LogLevel("INFO")
+	logFile := LogFile{logFilter: filt, fileName: testFileName, logPath: tempDir, MaxBytes: testBytes, duration: 24 * time.Hour}
 	logFile.Write([]byte("Hello World"))
 	logFile.Write([]byte("Second File"))
 	want := 2
@@ -57,3 +60,18 @@ func TestLogFile_byteRotation(t *testing.T) {
 		t.Errorf("Expected %d files, got %v file(s)", want, len(got))
 	}
 }
+
+func TestLogFile_logLevelFiltering(t *testing.T) {
+	t.Parallel()
+	tempDir := testutil.TempDir(t, "LogWriterTime")
+	defer os.Remove(tempDir)
+	filt := LevelFilter()
+	logFile := LogFile{logFilter: filt, fileName: testFileName, logPath: tempDir, MaxBytes: testBytes, duration: testDuration}
+	logFile.Write([]byte("[INFO] This is an info message"))
+	logFile.Write([]byte("[DEBUG] This is a debug message"))
+	logFile.Write([]byte("[ERR] This is an error message"))
+	want := 2
+	if got, _ := ioutil.ReadDir(tempDir); len(got) != want {
+		t.Errorf("Expected %d files, got %v file(s)", want, len(got))
+	}
+}
diff --git a/logger/logger.go b/logger/logger.go
index 9ae255a268..8a061936b2 100644
--- a/logger/logger.go
+++ b/logger/logger.go
@@ -123,7 +123,7 @@ func Setup(config *Config, ui cli.Ui) (*logutils.LevelFilter, *GatedWriter, *Log
 		if config.LogRotateBytes != 0 {
 			logRotateBytes = config.LogRotateBytes
 		}
-		logFile := &LogFile{fileName: fileName, logPath: dir, duration: logRotateDuration, MaxBytes: logRotateBytes}
+		logFile := &LogFile{logFilter: logFilter, fileName: fileName, logPath: dir, duration: logRotateDuration, MaxBytes: logRotateBytes}
 		writers = append(writers, logFile)
 	}