Getting started with ContainerSSH development

Welcome to developing ContainerSSH! For the purposes of this guide we will assume you have your development environment set up and ready to go. If not, please follow our handy guide to do just that.

Ready? Good.

Cloning the repository

Before we begin you will have to decide what you want to do. If you just want to get ContainerSSH running to get the big picture you will need to clone the ContainerSSH/ContainerSSH repository. This contains the main ContainerSSH executable, as well as the Auth-Config server used for testing:

git clone https://github.com/containerssh/containerssh

However, ContainerSSH is built in a highly modular fashion so you may need to change a specific library. You can find the list of libraries on our development dashboard. This dashboard contains an overview of all repositories, issues, pull requests, and everything else you will need to find your way around the codebase.

Each repository contains a readme explaining how to use that specific component. If you find the readme not helpful please open an issue on that repository asking for more information.

If you find yourself needing a new repository because you want to develop something completely new please file a pull request against the github-terraform repository.

Tip

For the best results we recommend cloning the ContainerSSH repos into /path/to/your/home/go/src/github.com/containerssh/REPONAME.

Running ContainerSSH

Running ContainerSSH is simple. You will need a clone of the main ContainerSSH repository. Then you have to run two commands.

First, the auth-config server needs to be run from the cmd/containerssh-testauthconfigserver directory:

go run .

When that's running create the cmd/containerssh/config.yaml file with the following content:

---
log:
  level: debug
ssh:
  hostkeys:
    - ssh_host_rsa_key
backend: dockerrun
auth:
  url: "http://127.0.0.1:8080"
  pubkey: false
configserver:
  url: "http://127.0.0.1:8080/config"

Now copy the ssh_host_rsa_key file from the example folder and then run ContainerSSH from the cmd/containerssh folder:

go run . --config config.yaml

That's it! Now you have a running ContainerSSH you can connect to on port 2222:

ssh foo@localhost -p 2222

Running the tests

There are two types of tests for ContainerSSH: end to end tests and component-level tests. Both can be run using the following command from each library's main folder:

go test ./...

Tip

Some tests require a working Docker or Kubernetes backend. Make sure that your Docker socket is running on your platform default and your Kubernetes configuration is available in the .kube/config file in your home directory as the tests will use these to connect to.

Submitting a pull requests

Once you are done with your development you should fork the repository on GitHub and create a pull request. This pull request will automatically be tested by the CI system. Feel free to keep working on your PR until you are happy with it.

Understanding ContainerSSH

ContainerSSH is a reasonably complex piece of software. It uses the built-in Go SSH library to create a server and the client libraries for Docker and Kubernetes to forward the data from the SSH channel to the standard input and output of the container.

We have dedicated a whole section to understanding how SSH and ContainerSSH in particular work.