action.sh

#!/usr/bin/env bash

set -e

ACTION_DIR="$(cd $(dirname "${BASH_SOURCE[0]}") >/dev/null 2>&1 && pwd)"

function usage {
	echo "Usage: ${0} --command=[start|stop] <arguments>"
}

function safety_on {
	set -o errexit -o pipefail -o noclobber -o nounset
}

function safety_off {
	set +o errexit +o pipefail +o noclobber +o nounset
}

source "${ACTION_DIR}/vendor/getopts_long.sh"

command=
runner_token=
project_id=
machine_zone=
machine_type=
boot_disk_type=
disk_size=
image_project=
image=
image_family=
label=
scopes=
shutdown_timeout=
task=

OPTLIND=1
while getopts_long :h opt \
	command required_argument \
	runner_token required_argument \
	project_id required_argument \
	machine_zone required_argument \
	machine_type required_argument \
	boot_disk_type optional_argument \
	disk_size optional_argument \
	image_project optional_argument \
	image optional_argument \
	image_family optional_argument \
	label optional_argument \
	scopes required_argument \
	shutdown_timeout required_argument \
	task required_argument \
	help no_argument "" "$@"; do
	case "$opt" in
	command)
		command=$OPTLARG
		;;
	runner_token)
		runner_token=$OPTLARG
		;;
	project_id)
		project_id=$OPTLARG
		;;
	machine_zone)
		machine_zone=$OPTLARG
		;;
	machine_type)
		machine_type=$OPTLARG
		;;
	boot_disk_type)
		boot_disk_type=${OPTLARG-$boot_disk_type}
		;;
	disk_size)
		disk_size=${OPTLARG-$disk_size}
		;;
	image_project)
		image_project=${OPTLARG-$image_project}
		;;
	image)
		image=${OPTLARG-$image}
		;;
	image_family)
		image_family=${OPTLARG-$image_family}
		;;
	label)
		label=${OPTLARG-$label}
		;;
	scopes)
		scopes=$OPTLARG
		;;
	shutdown_timeout)
		shutdown_timeout=$OPTLARG
		;;
	task)
		task=$OPTLARG
		;;
	h | help)
		usage
		exit 0
		;;
	:)
		printf >&2 '%s: %s\n' "${0##*/}" "$OPTLERR"
		usage
		exit 1
		;;
	esac
done

function start_vm {
	VM_ID="runner-$(echo ${GITHUB_RUN_ID}-${GITHUB_RUN_NUMBER}-${task} | sha1sum | cut -f 1 -d " ")"
	if [ ! -z "${label}" ]; then
		echo "Label provided, using it as VM ID (${label})"
		VM_ID="${label}"
	fi

	if [ ! -z "$(gcloud compute instances list | grep "${VM_ID}")" ]; then
		# the VM already exists.
		# this can happen when we call the action from a reusable workflow.
		# in these scenarios we don't want a new VM ;)
		echo "Skipping creation of new VM. Using the existing one (${VM_ID})"
		echo "label=${VM_ID}" >>"${GITHUB_OUTPUT}"
		echo "machine-zone=${machine_zone}" >>"${GITHUB_OUTPUT}"
		exit 0
	fi

	echo "Starting GCE VM ..."
	if [ -z "$runner_token" ]; then
		echo "❌ runner_token parameter is required"
		exit 1
	fi

	RUNNER_TOKEN=$(curl -S -s -XPOST \
		-H "Authorization: Bearer $runner_token" \
		"https://api.github.com/repos/$GITHUB_REPOSITORY/actions/runners/registration-token" |
		jq -r .token)
	if [ -z "$RUNNER_TOKEN" ]; then
		echo "❌ Failed to get a registration token"
		exit 1
	fi

	echo "✅ Successfully got the GitHub Runner registration token"

	image_project_flag=$([[ -z "${image_project}" ]] || echo "--image-project=${image_project}")
	image_flag=$([[ -z "${image}" ]] || echo "--image=${image}")
	image_family_flag=$([[ -z "${image_family}" ]] || echo "--image-family=${image_family}")
	disk_size_flag=$([[ -z "${disk_size}" ]] || echo "--boot-disk-size=${disk_size}")
	boot_disk_type_flag=$([[ -z "${boot_disk_type}" ]] || echo "--boot-disk-type=${boot_disk_type}")
	project_id_flag=$(echo "--project=${project_id}")

	echo "The new GCE VM will be ${VM_ID}"

	RUNNER_ID="${VM_ID}-$(date +%s)"

	cat <<FILE_EOF >/tmp/startup-script.sh
#!/bin/bash

set -e

# leeway temporal directories
chmod 777 /var/tmp
chmod 777 -R /var/tmp

cleanup() {
    echo "Removing runner..."
    REMOVE_TOKEN=\$(curl \
        -X POST \
        -H "Accept: application/vnd.github+json" \
        -H "Authorization: Bearer ${RUNNER_TOKEN}" \
        https://api.github.com/repos/${GITHUB_REPOSITORY}/actions/runners/remove-token | jq .token --raw-output)

    ./config.sh remove --token \${REMOVE_TOKEN}
}

trap 'cleanup; exit 130' INT
trap 'cleanup; exit 143' TERM

on_error() {
  echo "Error on line \$(caller)"
}

trap on_error ERR

cat <<-EOF >/etc/environment
	PATH="/home/runner/go-packages/bin:/home/runner/go/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin"
	GOPATH="/home/runner/go-packages"
	GOROOT="/home/runner/go"
EOF

# Create a systemd service in charge of shutting down the machine once the workflow has finished
cat <<-EOF >/etc/systemd/system/shutdown.sh
	#!/bin/sh
	sleep "${shutdown_timeout}"
	gcloud compute instances delete "${VM_ID}" --zone="${machine_zone}" --quiet
EOF

chmod +x /etc/systemd/system/shutdown.sh

echo "Registering runners ${RUNNER_ID}-1 and ${RUNNER_ID}-2..."
su -s /bin/bash -c "cd /actions-runner-1/;/actions-runner-1/config.sh --url https://github.com/${GITHUB_REPOSITORY} --token ${RUNNER_TOKEN} --name ${RUNNER_ID}-1 --labels ${VM_ID} --unattended --disableupdate" runner
su -s /bin/bash -c "cd /actions-runner-2/;/actions-runner-2/config.sh --url https://github.com/${GITHUB_REPOSITORY} --token ${RUNNER_TOKEN} --name ${RUNNER_ID}-2 --labels ${VM_ID} --unattended --disableupdate" runner

touch /.github-runner-config-ready

gcloud compute instances add-labels "${VM_ID}" --zone="${machine_zone}" --labels=gh_ready=1
echo "Setup complete."

FILE_EOF

	cat <<FILE_EOF >/tmp/shutdown-script.sh
#!/bin/bash

set -e

on_error() {
  echo "Error on line \$(caller)"
}

trap on_error ERR

echo "Removing runners ${RUNNER_ID}-1 and ${RUNNER_ID}-2..."

cd /actions-runner-1/
su -s /bin/bash -c "/actions-runner-1/config.sh remove --token ${RUNNER_TOKEN}" runner

cd /actions-runner-2/
su -s /bin/bash -c "/actions-runner-2/config.sh remove --token ${RUNNER_TOKEN}" runner

echo "Removed runners"

FILE_EOF

	chmod +x /tmp/startup-script.sh
	chmod +x /tmp/shutdown-script.sh

	gcloud compute instances create "${VM_ID}" \
		${project_id_flag} \
		--zone="${machine_zone}" \
		--labels="gh_ready=0" \
		${disk_size_flag} \
		${boot_disk_type_flag} \
		--machine-type="${machine_type}" \
		--scopes="${scopes}" \
		${image_project_flag} \
		${image_flag} \
		${image_family_flag} \
		--maintenance-policy="TERMINATE" \
		--metadata-from-file="startup-script=/tmp/startup-script.sh,shutdown-script=/tmp/shutdown-script.sh" &&
		echo "label=${VM_ID}" >>"${GITHUB_OUTPUT}"
		echo "machine-zone=${machine_zone}" >>"${GITHUB_OUTPUT}"

	safety_off
	set +x
	while ((i++ < 60)); do
		GH_READY=$(gcloud compute instances describe "${VM_ID}" --zone="${machine_zone}" --format='json(labels)' | jq -r .labels.gh_ready)
		if [[ $GH_READY == 1 ]]; then
			break
		fi
		echo "${VM_ID} not ready yet, waiting 5s ..."
		sleep 5
	done
	if [[ $GH_READY == 1 ]]; then
		echo "✅ ${VM_ID} ready ..."
	else
		echo "❌ Waited 5 minutes for ${VM_ID}, without luck, deleting ${VM_ID} ..."
		gcloud --quiet compute instances delete "${VM_ID}" --zone="${machine_zone}"
		exit 1
	fi
}

safety_on
case "$command" in
start)
	start_vm
	;;
*)
	echo "Invalid command: \`${command}\`, valid values: start" >&2
	usage
	exit 1
	;;
esac