bundle-problem-demo.sh

#!/usr/bin/env bash

function colorize_echo() { echo -e "\033[0;${1}m${@:2}\033[0m"; }
function red_echo()      { colorize_echo 31 $@; }
function green_echo()    { colorize_echo 32 $@; }
function yellow_echo()   { colorize_echo 33 $@; }
function blue_echo()     { colorize_echo 34 $@; }

CURRENT_DIR="$(pwd)"
DIR_NAME=docker-ruby-bundle-test
IMAGE_NAME=$DIR_NAME:latest

blue_echo "Create test dir"
mkdir -p $DIR_NAME

cd $DIR_NAME

blue_echo "Create dockerfile"
cat <<END > Dockerfile
FROM ruby:2.3

ADD Gemfile /tmp/bundle/
RUN cd /tmp/bundle && bundle install
END

blue_echo "Create gemfile"
cat <<END > Gemfile
# frozen_string_literal: true

source "https://rubygems.org"

git_source(:github) {|repo_name| "https://github.com/#{repo_name}" }

gem "json", "2.0.3"
END

blue_echo "Build docker image"
docker build --tag $IMAGE_NAME .

blue_echo "Problem demo A"
docker run --rm $IMAGE_NAME bash -c '
echo hostname:
hostname
echo pwd:
pwd
echo ls:
echo `ls`
echo bundle:
bundle'
red_echo "What? How pwd:/ can run bundle? Where is the Gemfile?"

blue_echo "Problem demo B"
docker run --rm $IMAGE_NAME bash -c '
echo hostname:
hostname
echo pwd:
pwd
echo ls:
echo `ls`
cat <<END > Gemfile
# frozen_string_literal: true
source "https://rubygems.org"

git_source(:github) {|repo_name| "https://github.com/#{repo_name}" }

gem "json", "2.0.4"
END
bundle'
red_echo "What? Why still use the json 2.0.3?"

blue_echo "Problem demo C"
docker run --rm $IMAGE_NAME bash -c '
cd /tmp/bundle
echo hostname:
hostname
echo pwd:
pwd
echo ls:
echo `ls`
cat <<END > Gemfile
# frozen_string_literal: true
source "https://rubygems.org"

git_source(:github) {|repo_name| "https://github.com/#{repo_name}" }

gem "json", "2.0.4"
END
bundle'
green_echo "OK... Now it works."

blue_echo "Cleanup"
docker rmi $IMAGE_NAME
cd "$CURRENT_DIR"
rm -rf $DIR_NAME