init

#!/usr/bin/env bash

pid=0

echoerr() { cat <<< "$@" 1>&2; }

if [ -z "$CONSUL_SERVERS" ]; then

    echoerr "CONSUL_SERVERS environment variable required. Exiting."
    exit 1
fi

if [ -z "$SERVICE_NAME" ]; then
    echoerr "SERVICE_NAME environment variable required. Exiting."
    exit 1
fi

if [ -z "$APP_PORT" ]; then
    echoerr "APP_PORT environment variable required. Exiting."
    exit 1
fi

SCRIPT_DIR="/usr/local/bin"
HEALTHY_CONSULS=$(${SCRIPT_DIR}/consul-health ${CONSUL_SERVERS} | tr "\n" ' ')

if [ -z "$HEALTHY_CONSULS" ]; then
    echoerr "No health Consul servers could be found. Exiting."
    exit 1
fi

echo "Found healthy Consul instances: ${HEALTHY_CONSULS}"

NODE_NAME="$(${SCRIPT_DIR}/zonealias)"

register() {
    local private_ip="$(${SCRIPT_DIR}/privateip)"
    local service_id="$(echo -n ${SERVICE_NAME} | tr -cd '[:alnum:] [:space:]' | tr '[:space:]' '-'  | tr '[:upper:]' '[:lower:]')"

    echoerr "Registering [$NODE_NAME] ($private_ip) to service [$SERVICE_NAME] ($service_id) with Consul"
    ${SCRIPT_DIR}/consul-register-node \
        -n "${NODE_NAME}" \
        -a "${private_ip}" \
        -s "${SERVICE_NAME}" \
        -i "${service_id}" \
        ${CONSUL_SERVERS}
}

deregister() {
    echoerr "Deregistering [$NODE_NAME] from Consul"
    ${SCRIPT_DIR}/consul-deregister-node -n ${NODE_NAME} ${CONSUL_SERVERS}
}

term_handler() {
  if [[ -n "$pid" ]] && [[ $pid -ne 0 ]]; then
    kill -SIGTERM "$pid"
    wait "$pid"
  fi
  exit 143
}

# Register current node with Consul
register

cd /app

# run application
su node -c "node ." &
pid="$!"

# Automatically deregister current node when init script exits
trap deregister EXIT
trap 'kill ${!}; term_handler' SIGINT SIGTERM

# wait indefinetely
while true
do
  tail -f /dev/null & wait ${!}
done