#!/usr/bin/env bash

# runs custom docker data root cleanup binary and debugs remaining resources
cleanup_dind() {
    if [[ "${DOCKER_IN_DOCKER_ENABLED:-false}" == "true" ]]; then
        echo "Cleaning up after docker"
        docker ps -q | xargs -r docker kill || true
        docker ps -aq | xargs -r docker rm -f || true
        docker system prune -af || true
        service docker stop || true
    fi
}

early_exit_handler() {
    if [ -n "${WRAPPED_COMMAND_PID:-}" ]; then
        kill -TERM "$WRAPPED_COMMAND_PID" || true
    fi
    cleanup_dind
}

# optionally enable ipv6 docker
export DOCKER_IN_DOCKER_IPV6_ENABLED=${DOCKER_IN_DOCKER_IPV6_ENABLED:-false}
if [[ "${DOCKER_IN_DOCKER_IPV6_ENABLED}" == "true" ]]; then
    echo "Enabling IPV6 for Docker."
    # configure the daemon with ipv6
    mkdir -p /etc/docker/
    cat <<EOF >/etc/docker/daemon.json
{
  "ipv6": true,
  "fixed-cidr-v6": "fc00:db8:1::/64"
}
EOF
    # enable ipv6
    sysctl net.ipv6.conf.all.disable_ipv6=0
    sysctl net.ipv6.conf.all.forwarding=1
    # enable ipv6 iptables
    modprobe -v ip6table_nat
fi

# Check if the job has opted-in to docker-in-docker availability.
export DOCKER_IN_DOCKER_ENABLED=${DOCKER_IN_DOCKER_ENABLED:-false}
if [[ "${DOCKER_IN_DOCKER_ENABLED}" == "true" ]]; then
    echo "Docker in Docker enabled, initializing..."
    printf '=%.0s' {1..80}; echo
    # If we have opted in to docker in docker, start the docker daemon,
    service docker start
    # the service can be started but the docker socket not ready, wait for ready
    WAIT_N=0
    MAX_WAIT=5
    while true; do
        # docker ps -q should only work if the daemon is ready
        docker ps -q > /dev/null 2>&1 && break
        if [[ ${WAIT_N} -lt ${MAX_WAIT} ]]; then
            WAIT_N=$((WAIT_N+1))
            echo "Waiting for docker to be ready, sleeping for ${WAIT_N} seconds."
            sleep ${WAIT_N}
        else
            echo "Reached maximum attempts, not waiting any longer..."
            break
        fi
    done
    printf '=%.0s' {1..80}; echo
    echo "Done setting up docker in docker."
fi

trap early_exit_handler INT TERM

# disable error exit so we can run post-command cleanup
set +o errexit

# add $GOPATH/bin to $PATH
export PATH="${GOPATH}/bin:${PATH}"
mkdir -p "${GOPATH}/bin"

# actually start bootstrap and the job
set -o xtrace
"$@" &
WRAPPED_COMMAND_PID=$!
wait $WRAPPED_COMMAND_PID
EXIT_VALUE=$?
set +o xtrace

# cleanup after job
if [[ "${DOCKER_IN_DOCKER_ENABLED}" == "true" ]]; then
    echo "Cleaning up after docker in docker."
    printf '=%.0s' {1..80}; echo
    cleanup_dind
    printf '=%.0s' {1..80}; echo
    echo "Done cleaning up after docker in docker."
fi

# preserve exit value from job / bootstrap
exit ${EXIT_VALUE}
