#!/bin/bash
# Yarn with Docker Boilerplate

# Boilerplate for my "[Using Yarn with Docker](https://medium.com/@mfornasa/using-yarn-with-docker-c116ad289d56)" post on Medium.

touch yarn.lock

# Init empty cache file
if [ ! -f .yarn-cache.tgz ]; then
  echo "Init empty .yarn-cache.tgz"
  tar cvzf .yarn-cache.tgz --files-from /dev/null
fi

docker build . -t yarn-demo

docker run --rm --entrypoint cat yarn-demo:latest /tmp/yarn.lock > /tmp/yarn.lock
if ! diff -q yarn.lock /tmp/yarn.lock > /dev/null  2>&1; then
  echo "Saving Yarn cache"
  docker run --rm --entrypoint tar yarn-demo:latest czf - /root/.yarn-cache/ > .yarn-cache.tgz
  echo "Saving yarn.lock"
  cp /tmp/yarn.lock yarn.lock
fi