How to use your SSH keys in a VSCode devcontainer

I absolutely love VSCode’s devcontainers feature, but I’ve never gotten them to work with my SSH keys. I’ve been writing my code in a container and then hopping out to WSL to run my fetches, pushes, and pulls. How bizarre! Well earlier today, I finally cracked the case, and here’s how you do it.

1. Obviously, create an SSH key. Here’s how I generated an ed25519 key, which was then stored in ~/.ssh/id_ed25519.

   > ssh-keygen -t ed25519 -C "EMAIL_ADDRESS"
   

2. Add your public key to the remote.
3. Add (or create) the following to a file at ~/.ssh/config. This tells your agent to forward your keys. You may want to restrict the host if you could be SSH-ing to multiple hosts.

   Host *
    ForwardAgent yes
   

4. Install socat and keychain for managing your agent.

   > sudo apt install -y socat keychain
   

5. Add the following to your ~/.config/fish/config.fish file. If you use a shell that isn’t fish, you’ll need to put it into your shell’s startup file and make some slight adjustments.

   eval (keychain --eval --agents ssh id_ed25519)
   

When you start the WSL distro, the agent will start and VSCode will forward your keys to the container!