Using a terminal in a browser

(by mutable.cc on 2022-10-30)

I'm interested in trying out more Cloud Native development practices. The first step I'd like to take, is to be able to spin up an arbitrary environment in some Cloud-based hosting, and use a terminal from it. I hope to build on this to enable more rapid software development, without having to set up or maintain a development environment.

Some general notes:

• It seems like for persistent sessions, you want to use screen or tmux to open the initial session, and resume it when web clients want to connect.
• Some 'web terminal' applications will just immediately serve a terminal on an HTTP port, whereas some others require manual interaction before a terminal is opened. The former seem more useful for automation, the latter more useful as a way to connect to other servers (from a bastion, say).
• There are sample Apache2 and Nginx configurations out there to redirect requests to different ports based on a URL prefix. Apache2 seems to be less encumbered (Nginx likes to lock up features behind a "Pro" version)

There are a lot of options out there. Here's what I've found so far:

WeTTY

A Node.js application to connect to a host via SSH and display the terminal in the browser. Pretty bare-bones functionality. The documentation is extremely thorough, and has lots of useful setup instructions, even for handling SAML2 logins.

To try out in Docker:

1. Run docker run --rm -p 3000:3000 wettyoss/wetty
2. Run docker exec -it passwd node and enter a new password.
3. Open a browser to http://localhost:3000/wetty and enter username node and the password.

ttyd

A C application that shares a TTY on the web. Basically a reimplementation of GoTTY below.

To try out in Docker:

1. Run docker run -it --rm -p 7681:7681 tsl0922/ttyd
2. Open a browser to http://localhost:7681/

GoTTY

A Go application that shares a TTY on the web. Has some useful functionality, seems fairly ideal for programmatically opening a terminal on a web port.

This is used by projects like webkubectl and gotty-web-users-Docker. There is a nifty client app for it too.

To try out in Docker:

1. Run docker run --rm -it -p 8080:8080 stevelaclasse/gotty-web-ssh /app/gotty -w sh -l
2. Open a browser to http://localhost:8080/

webssh

This is a Python app that allows you to SSH to hosts from a web terminal. The default is to give you a web interface to let you connect to an arbitrary host via SSH. However, you can pass URL queries to specify a hostname, username, password, and other default options.

This is definitely the "user-friendly" option if you just have a bastion and need to let users SSH from it. There is a setup guide here.

To try out in Docker:

1. Run git clone https://github.com/huashengdun/webssh.git
2. Run cd webssh
3. Run docker build -t webssh .
4. Run docker run --rm -p 8888:8888 --network=host webssh
5. Open a browser to http://localhost:8888/
6. Put in your local user's password and click 'Connect'