Custom Buildpack

Assumptions

• TBS 1.0.2 is deployed
  • Note: all steps leading up to the first step that uses the kp command can be done without TBS or kpack installed on a kubernetes cluster
• kp clusterstack list shows all stacks as READY

Steps

0. Export git repo dir to an env var to make future commands easier export ROOT_DIR=$PWD
1. Install pack CLI (https://github.com/buildpacks/pack)
2. git clone https://github.com/cloudfoundry-samples/spring-music
3. Set the default builder to the same one TBS uses pack set-default-builder <CONTAINER_REGISTRY_FQDN>/<TBS_PROJECT>/build-service/default
   • If you dont have TBS installed, you can just use the Paketo builder be running pack set-default-builder paketobuildpacks/builder:full
4. Make sure the image builds with the default builder pack build spring-music -p $ROOT_DIR/spring-music --trust-builder
5. When you run pack build spring-music -p $ROOT_DIR/spring-music -b $ROOT_DIR/sample-buildpack --trust-builder the following will happen:
   • sample-buildpack/bin/detect will be run from the root of the git repo specified (e.g. the spring-music directory) and determine whether or not to run whatever is in sample-buildpack/bin/build. In this case it will run because manifest.yml, inside the spring-music directory, contains the string "spring-music"
   • sample-buildpack/bin/detect will persist an environment variable called DEPENDENCIES_DIR that points to the directory (layer) where it will copy a file called helloworld
6. After running the above command, enter the container by running docker run -it --entrypoint launcher spring-music bash
7. Navigate to the layer directory that we added using the buildpack cd $DEPENDENCIES_DIR and inspect the file we copied in cat helloworld
8. Package the buildpack using pack package-buildpack helloworld-buildpack --config ./package.toml and see that it now exists in docker images
9. Use the packaged buildpack by running pack build spring-music -p $ROOT_DIR/spring-music -b helloworld-buildpack --trust-builder
10. Push the buildpack to your container repo docker tag helloworld-buildpack <CONTAINER_REGISTRY_FQDN>/<SOME_PROJECT>/<TBS_PROJECT>/helloworld-buildpack and docker push <CONTAINER_REGISTRY_FQDN>/<SOME_PROJECT>/<TBS_PROJECT>/helloworld-buildpack
11. Add the custom buildpack to the default clusterstore kp clusterstore add default -b <CONTAINER_REGISTRY_FQDN>/<SOME_PROJECT>/<TBS_PROJECT>/helloworld-buildpack and notice that it uploads it as <CONTAINER_REGISTRY_FQDN>/<SOME_PROJECT>/build-service/<BUILDPACK_ID>
12. Edit the default clusterbuilder and add this buildpack to the order
    • kubectl edit clusterbuilder default
    • Under spec.order add the following lines

      - group:
        - id: sample-buildpack
      

    • Ensure the buildpack is shown in the output of kp clusterbuilder status default
13. Build the image using TBS kp image create spring-music --tag <CONTAINER_REGISTRY_FQDN>/<SOME_PROJECT>/spring-music --git https://github.com/cloudfoundry-samples/spring-music --git-revision master
14. Pull the TBS-built container image down and verify the helloworld file is there:
    • docker pull <CONTAINER_REGISTRY_FQDN>/<SOME_PROJECT>/spring-music
    • docker run -it --entrypoint launcher spring-music bash
    • cd $DEPENDENCIES_DIR
    • cat helloworld