communicator/ssh: A first pass at SCP uploading

communicator/ssh/communicator.go

@@ -3,10 +3,12 @@ package ssh
 import (
 	"bytes"
 	"code.google.com/p/go.crypto/ssh"
+	"fmt"
 	"github.com/mitchellh/packer/packer"
 	"io"
 	"log"
 	"net"
+	"path/filepath"
 )
 
 type comm struct {
@@ -72,7 +74,64 @@ func (c *comm) Start(cmd string) (remote *packer.RemoteCommand, err error) {
 	return
 }
 
-func (c *comm) Upload(string, io.Reader) error {
+func (c *comm) Upload(path string, input io.Reader) error {
+	session, err := c.client.NewSession()
+	if err != nil {
+		return err
+	}
+
+	defer session.Close()
+
+	// Get a pipe to stdin so that we can send data down
+	w, err := session.StdinPipe()
+	if err != nil {
+		return err
+	}
+
+	// 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() {
+		if w != nil {
+			w.Close()
+		}
+	}()
+
+	// The target directory and file for talking the SCP protocol
+	target_dir := filepath.Dir(path)
+	target_file := filepath.Base(path)
+
+	// Start the sink mode on the other side
+	// TODO(mitchellh): There are probably issues with shell escaping the path
+	log.Println("Starting remote scp process in sink mode")
+	if err = session.Start("scp -t " + target_dir); err != nil {
+		return err
+	}
+
+	// Determine the length of the upload content by copying it
+	// into an in-memory buffer. Note that this means what we upload
+	// must fit into memory.
+	log.Println("Copying input data into in-memory buffer so we can get the length")
+	input_memory := new(bytes.Buffer)
+	if _, err = io.Copy(input_memory, input); err != nil {
+		return err
+	}
+
+	// Start the protocol
+	fmt.Fprintln(w, "C0644", input_memory.Len(), target_file)
+	io.Copy(w, input_memory)
+
+	// Close the stdin, which sends an EOF, and then set w to nil so that
+	// our defer func doesn't close it again since that is unsafe with
+	// the Go SSH package.
+	w.Close()
+	w = nil
+
+	// Wait for the SCP connection to close, meaning it has consumed all
+	// our data and has completed. Or has errored.
+	session.Wait()
+
+	// TODO(mitchellh): Check for return data (expect a 0 or error)
+
 	return nil
 }