Add cleanup function to close SSHAgent

builtin/provisioners/file/resource_provisioner.go

@@ -60,6 +60,7 @@ func (p *ResourceProvisioner) copyFiles(conf *helper.SSHConfig, src, dst string)
 	if err != nil {
 		return err
 	}
+	defer config.CleanupConfig()
 
 	// Wait and retry until we establish the SSH connection
 	var comm *helper.SSHCommunicator

builtin/provisioners/remote-exec/resource_provisioner.go

@@ -172,6 +172,7 @@ func (p *ResourceProvisioner) runScripts(
 	if err != nil {
 		return err
 	}
+	defer config.CleanupConfig()
 
 	o.Output(fmt.Sprintf(
 		"Connecting to remote host via SSH...\n"+

helper/ssh/communicator.go

@@ -97,6 +97,10 @@ type Config struct {
 
 	// NoPty, if true, will not request a pty from the remote end.
 	NoPty bool
+
+	// SSHAgentConn is a pointer to the UNIX connection for talking with the
+	// ssh-agent.
+	SSHAgentConn net.Conn
 }
 
 // New creates a new packer.Communicator implementation over SSH. This takes

helper/ssh/provisioner.go

@@ -103,6 +103,9 @@ func safeDuration(dur string, defaultDur time.Duration) time.Duration {
 // PrepareConfig is used to turn the *SSHConfig provided into a
 // usable *Config for client initialization.
 func PrepareConfig(conf *SSHConfig) (*Config, error) {
+	var conn net.Conn
+	var err error
+
 	sshConf := &ssh.ClientConfig{
 		User: conf.User,
 	}
@@ -113,7 +116,7 @@ func PrepareConfig(conf *SSHConfig) (*Config, error) {
 			return nil, fmt.Errorf("SSH Requested but SSH_AUTH_SOCK not-specified")
 		}
 
-		conn, err := net.Dial("unix", sshAuthSock)
+		conn, err = net.Dial("unix", sshAuthSock)
 		if err != nil {
 			return nil, fmt.Errorf("Error connecting to SSH_AUTH_SOCK: %v", err)
 		}
@@ -164,8 +167,17 @@ func PrepareConfig(conf *SSHConfig) (*Config, error) {
 	}
 	host := fmt.Sprintf("%s:%d", conf.Host, conf.Port)
 	config := &Config{
-		SSHConfig:  sshConf,
-		Connection: ConnectFunc("tcp", host),
+		SSHConfig:    sshConf,
+		Connection:   ConnectFunc("tcp", host),
+		SSHAgentConn: conn,
 	}
 	return config, nil
 }
+
+func (c *Config) CleanupConfig() error {
+	if c.SSHAgentConn != nil {
+		return c.SSHAgentConn.Close()
+	}
+
+	return nil
+}