Motivation

On the Launchpad Yellow squad we've been using Google hangouts to do pair programming and it's been quite effective. Unfortunately, sharing a terminal or editor via the screen sharing mechanism has a few drawbacks:

low-quality video means that only relatively large type is legible
laggy video means that the viewer is often waiting to see what the sender is doing/talking about
you can't see the person and the work at the same time
switching between viewing the work and the person is at the sender's discretion (instead of the viewer) and is not as light weight as would be desired
the viewer can not copy text from the shared screen
the remote person can only watch, no remote control is available

We've tried using screen to share sessions (see our how to at https://dev.launchpad.net/yellow/UsingScreen) but the setup was burdensome:

it meant opening up our development machines to ssh connections from the outside, a security concern for some
our machines are often on dynamic IPs, behind firewalls or routers and bridging those is irritating
it takes so long to set up a new pair that we are often discouraged from trying

We have also considered tmux and byobu but they have similar issues.

To address these issues I began building Termbeamer.

Pros:

any terminal size is usable
screen updates are nearly instantaneous
you can use this with any other communication system (skype, hangouts, mumble, etc.)
the viewer can copy text just as with any other terminal session
remote control: classical pair programming handoffs are possible
optional remote control: security worries are lessened relative to giving a remote user a local login
the connection is encrypted and doesn't require either viewer or host machines to be directly accessible from the Internet.

Cons:

the only transport currently available is XMPP which most people can use via Google Talk. The connections are encrypted, but Google could eavesdrop if they were so inclined.
terminal sharing only, no graphical applications

Development

The Termbeamer project is hosted on Launchpad at http://launchpad.net/termbeamer.

To get a develop environment set up, install the build dependencies, check out the source and then run the buildout:

    % sudo apt-get build-dep termbeamer
    % bzr branch lp:termbeamer
    % python2 bootstrap.py
    % bin/buildout

You can then run the tests.

    % bin/test

Test coverage can be generated:

    % bin/test --cover=cover

Or a quick coverage check is available:

    % ./list-uncovered-source-files

News

2012-06-18: Sections describing development, remote control, and using saved credentials added.

Installation

Termbeamer is packaged for Ubuntu and is available at https://launchpad.net/~benji/+archive/termbeamer.

You can install it by running

    % sudo add-apt-repository ppa:benji/termbeamer
    % sudo apt-get update
    % sudo apt-get upgrade
    % sudo apt-get install termbeamer

Setup

Termbeamer uses XMPP as its transport. The most easily available XMPP service is Google's "Talk" chat service.

To use Google Talk with Termbeamer open the GMail UI, search for the user's name in the chat box and then click "Invite to chat" on the resulting pop-up. The other user should also log into Gmail and accept the chat request. This only has to be done once.

Note: many people have multiple Google accounts, be sure to authorize the same accounts that will be used with Termbeamer.

Using with Google's two-factor authentication

Users of Google's two-factor authentication should create an application password for Google Talk by following the instructions at support.google.com/accounts/bin/answer.py?answer=185833. The generated password will be the one used when starting Termbeamer.

Running

Once the accounts have been authorized, the server and client can be started. Either may be started first.

Starting the server

To start a terminal session and stream it to someone else, run this command:

    % tb --xmpp-user=ME@gmail.com --xmpp-password=MY-PASSWORD --xmpp-send=OTHER-PERSON@gmail.com

A new window will appear running the user's default shell. Anything visible in this terminal will be sent to the other user. The host and viewer can be started at any time or restarted at any time without restarting the other.

It is recommended that a terminal multiplexer like GNU Screen be started once the new terminal is created to facilitate switching between multiple shell sessions and editors.

The user hosting the terminal session (but not yet the user viewing the session) can highlight a point on the screen by control-clicking. The clicked point will then be highlighted on the viewer's screen.

Starting the client

To start viewing someone elses terminal session, run this command:

    % tb --xmpp-user=ME@gmail.com --xmpp-password=MY-PASSWORD --xmpp-receive=OTHER-PERSON@gmail.com

Saving credentials

Typing credentials on the command line is tedious and potentially insecure (shoulder surfing). The user name and password can be saved to disk and are read when not otherwise provided:

    % tb --create-auth-file --xmpp-user=ME@gmail.com --xmpp-password=MY-PASSWORD

Remote control

If the --remote-control switch is provided when starting the server, any keystrokes typed into the client will be transmitted to the server and treated as if the local user typed them. This allows for pair programming between the local and remote user.

launchpad development

yellow/Termbeamer