How to create an offline buildpack

One of our problems is to have custom buildpack which doesn't need internet to find his dependencies. To deal with this issue cloudfoundry create 2 modules:

• buildpack packager wich download all your dependencies you set and make a zip file of your offline buildpack.
• compile extension is a module wich override curl command to find in cache if there is the dependencies and fallback to internet in other case

Prerequirements

• GIT
• Cygwin (if on windows)
• CNTLM (if under proxy ntlm)

If under proxy do this:

for git and cntlm run in terminal:

git config --global http.proxy http://localhost:3128
git config --global https.proxy http://localhost:3128

for curl and cntlm run in terminal

echo "proxy=http://localhost:3128" > ~/.curlrc

Tips for windows user:

you can have problem with End Of Line, you MUST HAVE unix EOL in your script file but git when you pull or clone with windows he will all EOL in windows format to bypass this do that in your terminal:

git config --system core.autocrlf false

Step 1

run your favorite terminal (if on windows prefer use cygwin) go to your buildpack source file with your terminal we will clone the both module from cloudfoundry in terminal:

git clone https://github.com/cf-buildpacks/buildpack-packager
git clone https://github.com/cf-buildpacks/compile-extensions

Step 2

create a new file insinde your bin directory called package and follow this content template:

#!/usr/bin/env bash
language='<your buildpack language>'
#to get url dependencies a little reverse engineering is needed, just look at pulled url inside your `bin/compile` file
dependencies=(
  'url of your first dependencies'
  'url of your second dependencies'
  '...'
)
excluded_files=(
  '.git/'
  '.gitignore'
  '.gitmodules'
  'repos/'
  'cf_spec/'
  'log/'
  'cf.Gemfile'
  'cf.Gemfile.lock'
  'bin/package'
  'buildpack-packager/'
)
BIN="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
source $BIN/../buildpack-packager/lib/packager

Step 3

you also need to modify your bin/compile put this in the beginning of your file:

# CF Common
BUILDPACK_PATH=$(cd $(dirname $0); cd ..; pwd)
export BUILDPACK_PATH
source $BUILDPACK_PATH/compile-extensions/lib/common
# END CF Common

Step 4

if you are under windows do this before dos2unix bin/* in your terminal Compile your offline package by doing this bin/package offline in your terminal At the end you will have a zip file with suffix offline you can create buildpack with this zip file

Step 5

Create a buildpack in cf with this command:

cf create-buildpack -offline  1

Step 6

Take a coffee, you've done :)