From 8ac9d9fe5cc82c4493c71b01f4d223fff157712a Mon Sep 17 00:00:00 2001
From: Richard Wall <richard.wall@jetstack.io>
Date: Wed, 24 Jan 2018 14:20:34 +0000
Subject: [PATCH] Feed the stdout and stderr of the Pilot subprocess into glog

Fixes: #166
---
 pkg/pilot/cassandra/v3/pilot.go               |  3 --
 pkg/pilot/elasticsearch/v5/process.go         |  2 -
 .../genericpilot/processmanager/process.go    | 50 ++++++++++++++++++-
 3 files changed, 49 insertions(+), 6 deletions(-)

diff --git a/pkg/pilot/cassandra/v3/pilot.go b/pkg/pilot/cassandra/v3/pilot.go
index 9656a5632..278d81932 100644
--- a/pkg/pilot/cassandra/v3/pilot.go
+++ b/pkg/pilot/cassandra/v3/pilot.go
@@ -2,7 +2,6 @@ package v3
 
 import (
 	"fmt"
-	"os"
 	"os/exec"
 
 	"k8s.io/client-go/tools/cache"
@@ -56,8 +55,6 @@ func (p *Pilot) CmdFunc(pilot *v1alpha1.Pilot) (*exec.Cmd, error) {
 	// The /run.sh script is unique to gcr.io/google-samples/cassandra:v12.
 	// TODO: Add support for other Cassandra images with different entry points.
 	cmd := exec.Command("/run.sh")
-	cmd.Stdout = os.Stdout
-	cmd.Stderr = os.Stderr
 	return cmd, nil
 }
 
diff --git a/pkg/pilot/elasticsearch/v5/process.go b/pkg/pilot/elasticsearch/v5/process.go
index b37548b33..acc249b0a 100644
--- a/pkg/pilot/elasticsearch/v5/process.go
+++ b/pkg/pilot/elasticsearch/v5/process.go
@@ -14,8 +14,6 @@ func (p *Pilot) CmdFunc(pilot *v1alpha1.Pilot) (*exec.Cmd, error) {
 	}
 
 	cmd := exec.Command("elasticsearch")
-	cmd.Stdout = os.Stdout
-	cmd.Stderr = os.Stderr
 	cmd.Env = p.env().Strings()
 
 	return cmd, nil
diff --git a/pkg/pilot/genericpilot/processmanager/process.go b/pkg/pilot/genericpilot/processmanager/process.go
index 7419e2f7e..746f10785 100644
--- a/pkg/pilot/genericpilot/processmanager/process.go
+++ b/pkg/pilot/genericpilot/processmanager/process.go
@@ -1,9 +1,13 @@
 package processmanager
 
 import (
+	"bufio"
 	"fmt"
 	"os"
 	"os/exec"
+	"sync"
+
+	"github.com/golang/glog"
 )
 
 type Interface interface {
@@ -41,13 +45,56 @@ type adapter struct {
 
 	doneCh  chan struct{}
 	doneErr error
+	wg      sync.WaitGroup
 }
 
 var _ Interface = &adapter{}
 
+func (p *adapter) startCommandOutputLoggers() error {
+	stdout, err := p.cmd.StdoutPipe()
+	if err != nil {
+		return err
+	}
+	p.wg.Add(1)
+	go func() {
+		defer p.wg.Done()
+		in := bufio.NewScanner(stdout)
+		for in.Scan() {
+			glog.Infoln(in.Text())
+		}
+		err := in.Err()
+		if err != nil {
+			glog.Error(err)
+		}
+	}()
+
+	stderr, err := p.cmd.StderrPipe()
+	if err != nil {
+		return err
+	}
+	p.wg.Add(1)
+	go func() {
+		defer p.wg.Done()
+		in := bufio.NewScanner(stderr)
+		for in.Scan() {
+			glog.Errorln(in.Text())
+		}
+		err := in.Err()
+		if err != nil {
+			glog.Error(err)
+		}
+	}()
+	return nil
+}
+
 // Start will start the underlying subprocess
 func (p *adapter) Start() error {
-	if err := p.cmd.Start(); err != nil {
+	err := p.startCommandOutputLoggers()
+	if err != nil {
+		return err
+	}
+
+	if err = p.cmd.Start(); err != nil {
 		return fmt.Errorf("error starting process: %s", err.Error())
 	}
 	go p.startWait()
@@ -71,6 +118,7 @@ func (p *adapter) Stop() error {
 // If the subprocess has not been started yet, the returned chan will
 // not close until the subprocess has been started and then stopped.
 func (p *adapter) Wait() <-chan struct{} {
+	defer p.wg.Wait()
 	return p.doneCh
 }