def pull_from_origin(repo_path):
    """Execute 'git pull' at the provided repo_path."""
    LOG.info("Pulling from origin at %s." % repo_path)
    command = GIT_PULL_CMD.format(repo_path)
    resp = envoy.run(command)
    if resp.status_code != 0:
        LOG.exception("Pull failed.")
        raise GitException(resp.std_err)
    else:
        LOG.info("Pull successful.")
Execute 'git pull' at the provided repo_path.