From d2fc90a3aab7b3849bcb28a688def4b305e8a7e9 Mon Sep 17 00:00:00 2001
From: Alana McKenzie <43767132+amckenzie132@users.noreply.github.com>
Date: Thu, 14 Apr 2022 10:32:06 -0700
Subject: [PATCH] Redirect standard logs (#5)

---
 CHANGELOG.md                   |  4 ++++
 internal/logger/logger.go      | 32 +++++++++++++++++++++++++++++
 internal/logger/logger_test.go | 37 ++++++++++++++++++++++++++++++++++
 pkg/proxy/proxy.go             |  5 +++++
 4 files changed, 78 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8bc6f0e9..b22e40b7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Load config from Config file, and from env vars. Use viper for that
 - Automatically alocates a random port, if the specified one is in-use
 
+## [0.1.18] - 2022-04-13
+## Changed
+- Redirect standard output to configured logger
+
 ## [0.1.17] - 2022-04-12
 ## Changed
 - Log request and response at INFO level
diff --git a/internal/logger/logger.go b/internal/logger/logger.go
index a043a1dc..82c9b0ca 100644
--- a/internal/logger/logger.go
+++ b/internal/logger/logger.go
@@ -5,10 +5,13 @@
 package logger
 
 import (
+	"bytes"
 	"fmt"
+	"io/ioutil"
 	"log"
 	"os"
 	"path/filepath"
+	"strings"
 	"time"
 
 	"github.com/go-playground/validator/v10"
@@ -112,5 +115,34 @@ type ProxyLogger struct {
 // Printf satisfies `goproxy` logging interface. Default logging level will be
 // `Debug`.
 func (pL *ProxyLogger) Printf(format string, v ...interface{}) {
+	format = strings.TrimSpace(format)
 	pL.Logger.Debuglnf(format, v...)
 }
+
+type StandardLogger struct {
+	Logger *sypl.Sypl
+}
+
+// Write satisfies the standard logging interface. Default logging level will be
+// `Debug`.
+func (pL *StandardLogger) Write(p []byte) (int, error) {
+	p = bytes.TrimSpace(p)
+	pL.Logger.Debug(string(p))
+	return len(p), nil
+}
+
+// RedirectStandardLogs redirects logs created with the standard library global logger
+// to the ProxyLogger.
+func RedirectStandardLogs() {
+	log.SetFlags(0)
+	log.SetPrefix("")
+	standardLogger := &StandardLogger{
+		Logger: Get().New("go"),
+	}
+	log.SetOutput(standardLogger)
+}
+
+// DisableStandardLogs disables logs created with the standard library global logger
+func DisableStandardLogs() {
+	log.SetOutput(ioutil.Discard)
+}
diff --git a/internal/logger/logger_test.go b/internal/logger/logger_test.go
index 4be7e1d1..4203d5a4 100644
--- a/internal/logger/logger_test.go
+++ b/internal/logger/logger_test.go
@@ -5,7 +5,15 @@
 package logger
 
 import (
+	"log"
+	"strings"
 	"testing"
+	
+	"github.com/saucelabs/sypl"
+	"github.com/saucelabs/sypl/level"
+	"github.com/saucelabs/sypl/output"
+	"github.com/saucelabs/sypl/processor"
+	"github.com/saucelabs/sypl/shared"
 )
 
 func TestSetup(t *testing.T) {
@@ -58,3 +66,32 @@ func TestSetup(t *testing.T) {
 		})
 	}
 }
+
+
+func TestRedirectStandardLogs(t *testing.T) {
+	// set global proxy logger
+	proxyLogger = sypl.NewDefault("test", level.Debug)
+	defer func(){proxyLogger = nil}()
+
+	// proxyLogger sends output to a buffer
+	buffer, outputBuffer := output.SafeBuffer(level.Trace, processor.PrefixBasedOnMask(shared.DefaultTimestampFormat))
+	proxyLogger.AddOutputs(outputBuffer)
+
+	// test standard logger before and after redirect
+	beforeMsg := "Before redirect"
+	afterMsg := "After redirect" 
+	log.Println(beforeMsg)
+	
+	RedirectStandardLogs()
+	log.Println(afterMsg)
+
+	bufferStr := buffer.String()
+
+	if strings.Contains(bufferStr, beforeMsg) {
+		t.Errorf("%s should not appear in proxy logger: %s", beforeMsg, bufferStr)
+	}
+	if !strings.Contains(bufferStr, afterMsg) {
+		t.Errorf("%s should appear in proxy logger: %s", afterMsg, bufferStr)
+	}
+
+}
\ No newline at end of file
diff --git a/pkg/proxy/proxy.go b/pkg/proxy/proxy.go
index b083b41e..5f47aa8d 100644
--- a/pkg/proxy/proxy.go
+++ b/pkg/proxy/proxy.go
@@ -602,6 +602,11 @@ func New(
 
 		proxy.Logger = proxyLogger
 		proxy.Verbose = true
+
+		// Ensure any standard log messages use a configured logger
+		logger.RedirectStandardLogs()
+	} else {
+		logger.DisableStandardLogs()
 	}
 
 	proxy.KeepDestinationHeaders = true