docker-machine/libmachine/drivers/utils.go

package drivers

import (
	"fmt"
	"time"

	"github.com/docker/machine/libmachine/log"
	"github.com/docker/machine/libmachine/mcnutils"
	"github.com/docker/machine/libmachine/ssh"
)

func GetSSHClientFromDriver(d Driver) (ssh.Client, error) {
	addr, err := d.GetSSHHostname()
	if err != nil {
		return nil, err
	}

	port, err := d.GetSSHPort()
	if err != nil {
		return nil, err
	}

	auth := &ssh.Auth{
		Keys: []string{d.GetSSHKeyPath()},
	}

	client, err := ssh.NewClient(d.GetSSHUsername(), addr, port, auth)
	return client, err

}

func RunSSHCommandFromDriver(d Driver, command string) (string, error) {
	client, err := GetSSHClientFromDriver(d)
	if err != nil {
		return "", err
	}

	log.Debugf("About to run SSH command:\n%s", command)

	output, err := client.Output(command)
	log.Debugf("SSH cmd err, output: %v: %s", err, output)
	if err != nil {
		returnedErr := fmt.Errorf(`Something went wrong running an SSH command!
command : %s
err     : %v
output  : %s
`, command, err, output)
		return "", returnedErr
	}

	return output, nil
}

func sshAvailableFunc(d Driver) func() bool {
	return func() bool {
		log.Debug("Getting to WaitForSSH function...")
		if _, err := RunSSHCommandFromDriver(d, "exit 0"); err != nil {
			log.Debugf("Error getting ssh command 'exit 0' : %s", err)
			return false
		}
		return true
	}
}

func WaitForSSH(d Driver) error {
	// Try to dial SSH for 30 seconds before timing out.
	if err := mcnutils.WaitForSpecific(sshAvailableFunc(d), 6, 5*time.Second); err != nil {
		return fmt.Errorf("Too many retries waiting for SSH to be available.  Last error: %s", err)
	}
	return nil
}