node-ssh-Forward

Another easy simple ssh lib for forwarding ports, command execution and interactive shell support.

Has in-built support for bastion hosts (also known as jump hosts).

• Installation
• Usage
• API

Installation

$ npm install node-ssh-forward

or

$ yarn add node-ssh-forward

Usage

Setting up the initial ssh connection (using a bastion host)

import { SSHConnection } from 'node-ssh-forward'

const sshConnection = new SSHConnection({
  endHost: 'example.com',
  bastionHost: 'my-bastion-host.com'
})

Port forwarding

$ ssh -L 9000:imgur.com:80 example.com

const sshConnection = new SSHConnection({
  endHost: 'example.com',
})
await sshConnection.forward({
  fromPort: 9000,
  toPort: 80,
  toHost: 'imgur.com'
})

Port forwarding and using a bastion/jump host

$ ssh -L 9000:localhost:80 -J your-jump-host.com example.com

const sshConnection = new SSHConnection({
  endHost: 'example.com',
  bastionHost: 'your-jump-host.com'
})
await sshConnection.forward({
  fromPort: 9000,
  toPort: 80,
})

Port forwarding and using a bastion/jump host with different user to jump host and end host

$ ssh -L 9000:localhost:80 -J [email protected] example.com

const sshConnection = new SSHConnection({
  endHost: 'example.com',
  bastionHost: 'your-jump-host.com',
  bastionUsername: 'your-jump-user'
})
await sshConnection.forward({
  fromPort: 9000,
  toPort: 80,
})

Executing a command on the remote server

const sshConnection = new SSHConnection({
  endHost: 'example.com',
  bastionHost: 'your-jump-host.com'
})
await sshConnection.executeCommand('uptime')

API

new SSHConnection(options)

Options are an object with following properties:

• username (optional): The username used for your ssh connection (equivalent to -l option). If not set, it first looks for an SSH_USERNAME environment variable. If that is not set, it fallbacks to USER environment variable.
• password (optional): Provide a password to authenticate with username and password, not private key. Also see skipAutoPrivateKey.
• privateKey (optional): Can be a string or Buffer that contains a private key. If not set, it fallbacks to ~/.ssh/id_rsa
• skipAutoPrivateKey (optional): Don't try and read ~/.ssh/id_rsa if no private key is provided
• agentForward (optional): Is a boolean which uses the ssh-agent for connection (defaults to false). If set defaults to the value of env.SSH_AUTH_SOCK (all platforms), then pageant on Windows if no SSH_AUTH_SOCK is present.
• agentSocket (optional): Provide your own path to the SSH Agent Socket you want to use. Useful if your app doesn't have access to ENV directly.
• endHost (required): The host you want to end up on (connect to)
• endPort (optional): Port number of the server. Needed in case the server runs on a custom port (defaults to 22)
• bastionHost (optional): You can specify a bastion host if you want
• bastionUsername (optional): You can specify the bastion username if you want, in case it is different from the user connecting to end host. If not provided while bastionHost is specified, connection will fall back to the username.
• passphrase (optional): You can specify the passphrase when you have an encrypted private key. If you don't specify the passphrase and you use an encrypted private key, you get prompted in the command line.
• noReadline (optional): Don't prompt for private key passphrases using readline (eg if this is not run in an interactive session)

connection.executeCommand(command: string): Promise<void>

Executes a command on the server. Promise will resolve after the command has been executed.

connection.tty(): Promise<void>

Starts an interactive shell session. Will resolve when then client has logged out from the server.

connection.forward(forwardOptions: Object)

Established port-forwarding. Promise resolves after the forwarding has been established. Forwarding can be stopped by calling connection.shutdown()

Possible options for forwardOptions:

• fromPort (required): Specifies the port on your local computer
• toPort (required): The port on endHost (specified in the SSHConnection options).
• toHost (optional): You can specify an additional toHost when you want to forward a port from a different server than your endHost.

connection.shutdown()

Closes all connections.

Developing

• Add your wanted feature to the implementation in ./src
• Add test in ./test/test.ts
• Run the test with ./test/test.sh

Limitations/Todos

• host based authentication
• Better documentation
• Debug logging
• Ability to pass an additional string to the forward that specifies when the promise is resolved and the forwarding is stopped