Relay forwarded ssh-agent to docker

relay_ssh_agent

#!/bin/bash

set -ex
set -o pipefail

# THIS MUST BE USED WITH AN SSH-AGENT THAT SUPPORTS CONFIRMATION/NOTIFICATION UPON A SIGNATURE REQUEST.

# Mount the sock to the docker
# docker run --user $(id -u):$(id -g) --rm -it -v "$HOME/.ssh/sshsock:/sshsock" -e SSH_AUTH_SOCK=/sshsock/sock ubuntu bash

ssh_sock_in_user_dir="$HOME/.ssh/sshsock/sock"
ssh_sock_in_tmp_dir="$(find /tmp ! -readable -prune -o -maxdepth 2 -type s -name "agent*" -user $USER -printf '%T@ %p\n' 2>/dev/null | sort -n | tail -1 | cut -d' ' -f2)"
[ -n "$ssh_sock_in_tmp_dir" ] || (echo "Cannot find agent, exiting"; exit 1)
mkdir -p "$(dirname $ssh_sock_in_user_dir)"
socat -dd UNIX-LISTEN:"$ssh_sock_in_user_dir",user=$(id -u),group=$(id -g),mode=0660,fork UNIX-CLIENT:"$ssh_sock_in_tmp_dir"