Move SSH code into a common util package. Add support for SSH tunnels.

test/e2e/util.go

@@ -19,7 +19,6 @@ package e2e
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"math"
 	"math/rand"
 	"os"
@@ -956,41 +955,7 @@ func SSH(cmd, host, provider string) (string, string, int, error) {
 		return "", "", 0, fmt.Errorf("error getting signer for provider %s: '%v'", provider, err)
 	}
 
-	// Setup the config, dial the server, and open a session.
-	config := &ssh.ClientConfig{
-		User: os.Getenv("USER"),
-		Auth: []ssh.AuthMethod{ssh.PublicKeys(signer)},
-	}
-	client, err := ssh.Dial("tcp", host, config)
-	if err != nil {
-		return "", "", 0, fmt.Errorf("error getting SSH client to host %s: '%v'", host, err)
-	}
-	session, err := client.NewSession()
-	if err != nil {
-		return "", "", 0, fmt.Errorf("error creating session to host %s: '%v'", host, err)
-	}
-	defer session.Close()
-
-	// Run the command.
-	code := 0
-	var bout, berr bytes.Buffer
-	session.Stdout, session.Stderr = &bout, &berr
-	if err = session.Run(cmd); err != nil {
-		// Check whether the command failed to run or didn't complete.
-		if exiterr, ok := err.(*ssh.ExitError); ok {
-			// If we got an ExitError and the exit code is nonzero, we'll
-			// consider the SSH itself successful (just that the command run
-			// errored on the host).
-			if code = exiterr.ExitStatus(); code != 0 {
-				err = nil
-			}
-		} else {
-			// Some other kind of error happened (e.g. an IOError); consider the
-			// SSH unsuccessful.
-			err = fmt.Errorf("failed running `%s` on %s: '%v'", cmd, host, err)
-		}
-	}
-	return bout.String(), berr.String(), code, err
+	return util.RunSSHCommand(cmd, host, signer)
 }
 
 // getSigner returns an ssh.Signer for the provider ("gce", etc.) that can be
@@ -1012,21 +977,7 @@ func getSigner(provider string) (ssh.Signer, error) {
 	key := filepath.Join(keydir, keyfile)
 	Logf("Using SSH key: %s", key)
 
-	// Create an actual signer.
-	file, err := os.Open(key)
-	if err != nil {
-		return nil, fmt.Errorf("error opening SSH key %s: '%v'", key, err)
-	}
-	defer file.Close()
-	buffer, err := ioutil.ReadAll(file)
-	if err != nil {
-		return nil, fmt.Errorf("error reading SSH key %s: '%v'", key, err)
-	}
-	signer, err := ssh.ParsePrivateKey(buffer)
-	if err != nil {
-		return nil, fmt.Errorf("error parsing SSH key %s: '%v'", key, err)
-	}
-	return signer, nil
+	return util.MakePrivateKeySigner(key)
 }
 
 // LatencyMetrics stores data about request latency at a given quantile