SSH_AGENT_FILE="$HOME/.local/var/ssh-agent"

load_ssh_agent() {
  [ ! -f "$SSH_AGENT_FILE" ] && return 1
  source "$SSH_AGENT_FILE"
  [ -z "$SSH_AGENT_PID" ] || [ -z "$SSH_AUTH_SOCK" ] && return 1
  ! ps -p $SSH_AGENT_PID > /dev/null && return 1
  [ "$(ps -o command= $SSH_AGENT_PID)" != "ssh-agent" ] && return 1
  [ ! -e "$SSH_AUTH_SOCK" ] && return 1
  return 0
}

ssh_agent() {
  if load_ssh_agent ; then
    echo "Loading ssh-agent successful"
  else
    echo "Loading ssh-agent failed. Starting a new ssh-agent"
    SSH_AGENT_DIR="$(dirname "$SSH_AGENT_DIR")"
    [ ! -d "$SSH_AGENT_DIR" ] && mkdir -p "$SSH_AGENT_DIR"
    ssh-agent | head -n 2 > "$SSH_AGENT_FILE"
    source "$SSH_AGENT_FILE"
  fi
  return 0
}

ssh_agent