From ebd14bb2dfa4c5fd001c24bf54122a2b5aa3ee05 Mon Sep 17 00:00:00 2001
From: Mark Peek <mark@peek.org>
Date: Wed, 17 Jul 2013 18:15:42 -0700
Subject: [PATCH 1/2] Return errors from remote scp command

Currently file provisioners will silently fail when there is an error
with the remote side. This commit checks the scp error code and will
return the error message from the remote.
---
 communicator/ssh/communicator.go | 42 ++++++++++++++++++++++++++------
 1 file changed, 35 insertions(+), 7 deletions(-)

diff --git a/communicator/ssh/communicator.go b/communicator/ssh/communicator.go
index dacd46807..c1fbc5e52 100644
--- a/communicator/ssh/communicator.go
+++ b/communicator/ssh/communicator.go
@@ -1,6 +1,7 @@
 package ssh
 
 import (
+	"bufio"
 	"bytes"
 	"code.google.com/p/go.crypto/ssh"
 	"errors"
@@ -106,12 +107,6 @@ func (c *comm) Upload(path string, input io.Reader) error {
 		return err
 	}
 
-	// Set stderr/stdout to a bytes buffer
-	stderr := new(bytes.Buffer)
-	stdout := new(bytes.Buffer)
-	session.Stderr = stderr
-	session.Stdout = stdout
-
 	// We only want to close once, so we nil w after we close it,
 	// and only close in the defer if it hasn't been closed already.
 	defer func() {
@@ -120,6 +115,17 @@ func (c *comm) Upload(path string, input io.Reader) error {
 		}
 	}()
 
+	// Get a pipe to stdout so that we can get responses back
+	scp_reader, err := session.StdoutPipe()
+	if err != nil {
+		return err
+	}
+	r := bufio.NewReader(scp_reader)
+
+	// Set stderr to a bytes buffer
+	stderr := new(bytes.Buffer)
+	session.Stderr = stderr
+
 	// The target directory and file for talking the SCP protocol
 	target_dir := filepath.Dir(path)
 	target_file := filepath.Base(path)
@@ -143,8 +149,17 @@ func (c *comm) Upload(path string, input io.Reader) error {
 	// Start the protocol
 	log.Println("Beginning file upload...")
 	fmt.Fprintln(w, "C0644", input_memory.Len(), target_file)
+	err = check_response(r)
+	if err != nil {
+		return err
+	}
+
 	io.Copy(w, input_memory)
 	fmt.Fprint(w, "\x00")
+	err = check_response(r)
+	if err != nil {
+		return err
+	}
 
 	// TODO(mitchellh): Each step above results in a 0/1/2 being sent by
 	// the remote side to confirm. We should check for those confirmations.
@@ -178,7 +193,6 @@ func (c *comm) Upload(path string, input io.Reader) error {
 		return err
 	}
 
-	log.Printf("scp stdout (length %d): %#v", stdout.Len(), stdout.Bytes())
 	log.Printf("scp stderr (length %d): %s", stderr.Len(), stderr.String())
 
 	return nil
@@ -223,3 +237,17 @@ func (c *comm) reconnect() (err error) {
 
 	return
 }
+
+func check_response(r *bufio.Reader) (err error) {
+	scp_status_code, err := r.ReadByte()
+	if err != nil {
+		return err
+	}
+	if scp_status_code != 0 {
+		// Treat any non-zero (really 1 and 2) as fatal errors
+		error_message, _, err := r.ReadLine()
+		err = fmt.Errorf(string(error_message[:]))
+		return err
+	}
+	return nil
+}

From 0403932315cb6c8ae074f40660da40c40b02ac38 Mon Sep 17 00:00:00 2001
From: Mark Peek <mark@peek.org>
Date: Wed, 17 Jul 2013 18:17:46 -0700
Subject: [PATCH 2/2] Log an upload error closer to when it occurs

When there is an error returned from the Upload it is propagated back
to the main loop and may have additional log messages before the actual
error is displayed. This displays a log message close to where the error
actually occurred.
---
 provisioner/file/provisioner.go | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/provisioner/file/provisioner.go b/provisioner/file/provisioner.go
index 1a9a3589b..25811dbb9 100644
--- a/provisioner/file/provisioner.go
+++ b/provisioner/file/provisioner.go
@@ -79,5 +79,9 @@ func (p *Provisioner) Provision(ui packer.Ui, comm packer.Communicator) error {
 	}
 	defer f.Close()
 
-	return comm.Upload(p.config.Destination, f)
+	err = comm.Upload(p.config.Destination, f)
+	if err != nil {
+		ui.Error(fmt.Sprintf("Upload failed: %s", err))
+	}
+	return err
 }