A script for forwarding your gpg-agent to gitpod

forward-gpg-agent-to-gitpod.sh

#!/bin/bash
set -euo pipefail

opt=${1:-}

usage() {
  echo "$0 - ssh into a remote gitpod with your gpg-agent forwarded"
  echo
  echo "usage: $0 [option]"
  echo
  echo "Options are one of:"
  echo "  --help / -h    This help"
  echo "  --ssh          SSH directly into the gitpod instance with your gpg-agent forwarded"
  echo "  --configure    Output the ssh configuration file to STDOUT"
  echo
  echo "Before running this script you should have a local vscode instance open"
  echo "and connected to a remote gitpod workspace."
  echo "This script will attempt to find the latest gitpod ssh config that the vscode"
  echo "extension writes to /tmp/gitpod_ssh_config*"
}
if [[ "$opt" == "--help" || "$opt" == "-h" ]]; then
  usage
  exit 0
fi

function generate_config() {
set +e
if ! gpg --card-status &> /dev/null; then
  echo "Error: No gpg smartcard detected"
  exit 1
fi
set -e

GPG_AGENT_EXTRA=$(gpgconf --list-dir agent-extra-socket)

GITPOD_SSH_CONFIG=$(find /tmp -maxdepth 1 -name "gitpod_ssh_config*" -print0 |\
    xargs -r -0 ls -1 -t | \
    head -1)

if [ ! -f "$GITPOD_SSH_CONFIG" ]; then
  echo "Error: No gitpod ssh config found in /tmp"
  echo "Are you connected to a gitpod?"
  exit 1
fi

PORT_IDFILE=$(cat $GITPOD_SSH_CONFIG | awk -v RS= -v FS=\\n -v IGNORECASE=1 ' 
    {
        ip = ""
        alias = ""
        id_file = ""
        port = ""
        for (j = 1; j <= NF; ++j) {
            split($j, tmp, " ")
            if (tmp[1] == "Host") { alias = tmp[2] }
            if (tmp[1] == "Hostname") { ip = tmp[2] }
            if (tmp[1] == "IdentityFile") { id_file = tmp[2] }
            if (tmp[1] == "Port") { port = tmp[2] }
        }
        if (ip || alias && alias != "*") {
            print port "\t" id_file
        }
    }
    ');
read port idfile <<< "$PORT_IDFILE"
cat << EOF
#
# To use this config:
# 1. Connect to a remote gitpod workspace with vscode
# 2. Inside the gitpod run:
  gpgconf --kill all
  rm /home/gitpod/.gnupg/S.gpg-agent
# 3. Locally run 'ssh -F gitpod.ssh gitpod' where gitpod.ssh is the output of the script
#
Host gitpod
HostName 127.0.0.1
User gitpod
Port $port
IdentityFile $idfile
RemoteForward /home/gitpod/.gnupg/S.gpg-agent $GPG_AGENT_EXTRA
IdentitiesOnly yes
EOF
}

if [[ "$opt" == "--ssh" ]]; then
  ssh_config="$(generate_config)"
  tdir=$(mktemp -d "${TMPDIR:-/tmp/}$(basename $0).XXXXXXXXXXXX")
  echo "$ssh_config" > "$tdir/gitpod.ssh"
  ssh -t -F "$tdir/gitpod.ssh" gitpod  "gpgconf --kill all && rm /home/gitpod/.gnupg/S.gpg-agent" &> /dev/null
  set +e
  ssh -F "$tdir/gitpod.ssh" gitpod
  rm -rf "$tdir"
elif [[ "$opt" == "--configure" ]]; then
  generate_config
else
  usage
  exit 0
fi