provision_git_user.sh

ConfigureAccessFromUserGit () {
  if ! getent passwd git >/dev/null 2>&1; then
    adduser git
    su - -s /bin/bash git <<SU
      mkdir .ssh
      chmod 700 .ssh
      touch .ssh/authorized_keys
      chmod 600 .ssh/authorized_keys
SU

    git_shell=$(which git-shell)
    set +e
    if ! grep ${git_shell} /etc/shells >/dev/null ; then
      echo ${git_shell} >> /etc/shells
    fi
    set -e

    chsh -s ${git_shell} git

    su - -s /bin/bash git <<SU
      mkdir git-shell-commands
      touch git-shell-commands/no-interactive-login
SU
      cat >/home/git/git-shell-commands/no-interactive-login <<'EOF'
#!/bin/sh

printf '%s\n' "Hi $USER! You've successfully authenticated, but I do not"
printf '%s\n' "provide interactive shell access."
exit 128
EOF
      chmod +x /home/git/git-shell-commands/no-interactive-login
  else
    echo "User git already exists"
  fi
}

GrantAccessProjectRootToGitAndViceVersa () {
  if [ ! -f "/home/git/.ssh/id_rsa.pub" ]; then
    su - -s /bin/bash git <<SU
      ssh-keygen -t rsa -f ~/.ssh/id_rsa -N ''
SU
    git_key=$(cat /home/git/.ssh/id_rsa.pub)
    echo "# git@${host_name}" >> ~/.ssh/authorized_keys
    echo ${git_key} >> ~/.ssh/authorized_keys

    root_key=$(cat ~/.ssh/id_rsa.pub)
    echo "# root@${host_name}" >> /home/git/.ssh/authorized_keys
    echo ${root_key} >> /home/git/.ssh/authorized_keys
    ssh -o StrictHostKeyChecking=no git@${host_name} <<SSH
      echo "loggined in as git user"
SSH
  else
    echo "SSH key /home/git/.ssh/id_rsa.pub already exists"
  fi
}

CreateReposDir () {
  if [ ! -d "${repos_dir}" ]; then
    mkdir -p ${repos_dir}
    chown git:git ${repos_dir}
  else
    echo "Dir ${repos_dir} already exists"
  fi
}

PutFileUnderVersionControl () {
  target_file=$1
  versioned_file=$2
  if [ ! -f "${target_file}" ]; then
    echo "file ${target_file} not found"
    exit 1
  fi
  if [ ! -h "${target_file}" ]; then
    mv ${target_file} ${configs_dir}/${versioned_file}
    ln -s ${configs_dir}/${versioned_file} ${target_file}
    cd ${configs_dir}
    git add ${versioned_file}
    git commit -m "File ${target_file} linked as file ${configs_dir}/${versioned_file}"
    git pull --rebase
    git push
  else
    echo "File ${target_file} already linked as $(ls -al ${target_file})"
  fi
}

InitGitRepos () {
  ConfigureAccessFromUserGit
  GrantAccessProjectRootToGitAndViceVersa
  CreateReposDir
  PutFileUnderVersionControl /home/git/.ssh/authorized_keys git_authorized_keys
}