ssh

README

Origin README see here

This ssh package contains helpers for working with ssh in go. The client.go file is a modified version of docker/machine/libmachine/ssh/client.go that only uses golang's native ssh client. It has also been improved to resize the tty as needed. The key functions are meant to be used by either client or server and will generate/store keys if not found.

Usage:

package main

import (
	"fmt"

	"github.com/nanobox-io/golang-ssh"
)

func main() {
	err := connect()
	if err != nil {
		fmt.Printf("Failed to connect - %s\n", err)
	}
}

func connect() error {
    client, err := ssh.NewNativeClient("user", "localhost", "SSH-2.0-MyCustomClient-1.0", 2222, nil, ssh.AuthPassword("pass"))
	if err != nil {
		return fmt.Errorf("Failed to create new client - %s", err)
	}

	err = client.Shell()
	if err != nil && err.Error() != "exit status 255" {
		return fmt.Errorf("Failed to request shell - %s", err)
	}

	return nil
}

Compile for Windows:

If you get this error:

go: github.com/Sirupsen/logrus@v1.2.0: parsing go.mod: unexpected module path "github.com/sirupsen/logrus"

when compile for Windows with go mod, see this issue for some hints and there was a walkaround:

go mod init
go get github.com/docker/docker@v0.0.0-20180422163414-57142e89befe
GOOS=windows GOARCH=amd64 go build

Documentation

Overview

Package ssh is a helper for working with ssh in go. The client implementation is a modified version of `docker/machine/libmachine/ssh/client.go` and only uses golang's native ssh client. It has also been improved to resize the tty accordingly. The key functions are meant to be used by either client or server and will generate/store keys if not found.

Index

• func AuthCert(keyReader, certReader io.Reader) (ssh.AuthMethod, error)
• func AuthCertFile(keyFilename, certFilename string) (ssh.AuthMethod, error)
• func AuthKey(r io.Reader) (ssh.AuthMethod, error)
• func AuthKeyFile(keyFilename string) (ssh.AuthMethod, error)
• func AuthPassword(password string) ssh.AuthMethod
• func GenKeyPair() (string, string, error)
• func GetKeyPair(file string) (string, string, error)
• func Output(ctx context.Context, config Config, command string, stdout, stderr io.Writer) error
• func OutputWithPty(ctx context.Context, config Config, command string, stdout, stderr io.Writer) error
• func ParseCertificate(cert []byte) (*ssh.Certificate, error)
• func Shell(ctx context.Context, config Config, stdin io.Reader, stdout, stderr io.Writer, ...) error
• type Client
  • func NewClient(cfg Config) *Client
  • func (client *Client) Start(ctx context.Context, command string) (io.WriteCloser, io.Reader, io.Reader, error)
  • func (client *Client) Wait() (err error)
• type Config
• type ExitError
  • func (err *ExitError) Cause() error
  • func (err *ExitError) Error() string

Functions

func AuthCert

func AuthCert(keyReader, certReader io.Reader) (ssh.AuthMethod, error)

AuthCert creates an AuthMethod for SSH certificate authentication from the key and certificate bytes.

func AuthCertFile

func AuthCertFile(keyFilename, certFilename string) (ssh.AuthMethod, error)

AuthCertFile creates an AuthMethod for SSH certificate authentication from the key and certicate files.

func AuthKey

func AuthKey(r io.Reader) (ssh.AuthMethod, error)

AuthKey creates an AuthMethod for SSH key authentication.

func AuthKeyFile

func AuthKeyFile(keyFilename string) (ssh.AuthMethod, error)

AuthKey creates an AuthMethod for SSH key authentication from a key file.

func AuthPassword

func AuthPassword(password string) ssh.AuthMethod

AuthPassword creates an AuthMethod for password authentication.

func GenKeyPair

func GenKeyPair() (string, string, error)

GenKeyPair make a pair of public and private keys for SSH access. Public key is encoded in the format for inclusion in an OpenSSH authorized_keys file. Private Key generated is PEM encoded

func GetKeyPair

func GetKeyPair(file string) (string, string, error)

GetKeyPair will attempt to get the keypair from a file and will fail back to generating a new set and saving it to the file. Returns pub, priv, err

func Output

func Output(ctx context.Context, config Config, command string, stdout, stderr io.Writer) error

Output returns the output of the command run on the remote host.

func OutputWithPty

func OutputWithPty(ctx context.Context, config Config, command string, stdout, stderr io.Writer) error

Output returns the output of the command run on the remote host as well as a pty.

func ParseCertificate

func ParseCertificate(cert []byte) (*ssh.Certificate, error)

func Shell

func Shell(ctx context.Context, config Config, stdin io.Reader, stdout, stderr io.Writer, args ...string) error

Shell requests a shell from the remote. If an arg is passed, it tries to exec them on the server.

Types

type Client

type Client struct {
	Config

	sync.Mutex
	// contains filtered or unexported fields
}

func NewClient

func NewClient(cfg Config) *Client

NewClient creates a new Client using the golang ssh library.

func (*Client) Start

func (client *Client) Start(ctx context.Context, command string) (io.WriteCloser, io.Reader, io.Reader, error)

Start starts the specified command without waiting for it to finish. You have to call the Wait function for that.

func (*Client) Wait

func (client *Client) Wait() (err error)

Wait waits for the command started by the Start function to exit. The returned error follows the same logic as in the exec.Cmd.Wait function.

type Config

type Config struct {
	User          string              // username to connect as, required
	Host          string              // hostname to connect to, required
	ClientVersion string              // ssh client version, "SSH-2.0-Go" by default
	Port          int                 // port to connect to, 22 by default
	Auth          []ssh.AuthMethod    // authentication methods to use
	Timeout       time.Duration       // connect timeout, 30s by default
	DialRetry     int                 // number of dial retries, 0 (no retries) by default
	HostKey       ssh.HostKeyCallback // callback for verifying server keys, ssh.InsecureIgnoreHostKey by default
}

type ExitError

type ExitError struct {
	Err      error
	ExitCode int
}

ExitError is a convenience wrapper for (crypto/ssh).ExitError type.

func (*ExitError) Cause

func (err *ExitError) Cause() error

Cause implements errors.Causer interface.

func (*ExitError) Error

func (err *ExitError) Error() string

Error implements error interface.