If you’re working with multiple git repositories and you are using deploy keys you might keep encountering authentication issues. In my case I was trying to
pip install a module from a different repository than that where the build was running. I kept getting
ERROR: Repository not found.
fatal: Could not read from remote repository.
After much thrashing and checking, double checking keys, I found the source of the problem. CircleCI runs a ssh-agent and preloads your project keys. This means that when your pip command runs it connects to github with a key that authenticates correctly but is not authorized to access the other repository even though the right key is in ssh-agent. The right key never gets used because a prior key is accepted at the ssh level!
To enforce a single key being used you need to
run: echo $SSH_KEY_STORED_IN_CCI > ~/.ssh/id_rsa run: chmod 400 ~/.ssh/id_rsa run: unset SSH_AUTH_SOCK && /command/connecting/to/github
Do not put the
unset and the command connecting to github on separate lines as it looks like CCI resets the shell environment between commands.