Cloud Pak for Applications Stack Hub

This repository provides a default Stack Hub for IBM Cloud Pak for Applications.

repository structure

The repository contains four folders:

1. config - This folder is where the configuration file that defines the content of the Stack Hub repository will be placed.
2. scripts - This folder contains the scripts that will compose the Stack Hub repository
3. example_config - This folder contains sample configuration files.
4. templates - This folder contains template configuration files that can be used as a starting point for a Stack Hub repositories configuration.

Stack Hub Repository

A Stack Hub repository is a collection of meta-data for a group of stacks. Stack Hub repositories support Appsody development stacks.

Creating a Stack Hub repository

repo-tools is a template repository and should be used as the base for your Stack Hub repository. To create a Stack Hub repository follow the GitHub documentation using the icp4apps/repo-tools repository as the template.

Defining your configuration

Before building a Stack Hub repository you need to create the configuration that identifies what the repository will include.

Including Appsody stacks

Appsody stacks can be included in your Stack Hub by adding a configuration file with the following configuration to your Stack Hubs config folder:

# Template for repo-tools configuration
name: <Repository name>
description: <Repository description> 
version: <Repository version>
stacks:
  - name: <Repository index name>
    repos:
      - url: <Reference to index file>
        exclude:
            - <stack name>
        include:
            - <stack name>
image-org: <Organisation containing images within registry>
image-registry: <Image registry hosting images>
nginx-image-name: <Image name for the generated nginx image, defaults to repo-index>

where:
name: is an identifier for this particular configuration
description: is a description of the configuration
version: is a version for the configuration, may align with a repository release.
stacks: - name: is the name of a repository to be built.
stacks: repos: is an array of urls to stack indexes / repositories to be included in this repository index
stacks: repos: -url: exclude: is an array of stack names to exclude from the referenced stack repository. This field is optional and should be left blank if filtering is not required.
stacks: repos: -url: include: is an array of stack names to include from the referenced stack repository. This field is optional and should be left blank if filtering is not required.
image-org: is the name of the organisation within the image registry which will store the docker images for included stacks. This field is optional and controls the behaviour of the repository build, further details are available below.
image-registry: is the url of the image registry being used to store stack docker images. This field is optional and controls the behaviour of the repository build, further details are available below.
nginx-image-name: is the name assigned to the generated nginx image, defaults to repo-index.

NOTES

• exclude/include are mutually exclusive, if both fields are populated an error will be thrown.
• If the stack index url follows the https://<ghe host>/<organisation>/<repository>/releases/download/<version>/<file name> format, the GitHub Enterprise API will be used to download the artifacts. To provide the access token for the GitHub Enterprise API, set an environment variable based on the server host name. For example, if your server is github.example.com set GITHUB_EXAMPLE_COM_TOKEN environment variable with the token.

Composition of public stacks / repositories.

If the stacks and repositories you are including are all publicly available then repo-tools can simply compose a new repository file that uses references to the existing stack asset locations. When this type of build is required simply leave the image-org and image-registry fields of your configuration empty. The composed repository files will be stored in the assets folder generated when the tools are run.

Packaging private stacks / repositories.

If your stacks / repositories are hosted in a private environment that your deployment environment and tools cannot access, such as GitHub Enterprise, you can leverage the repo-tools to create an NGINX image that can serve the assets required to make use of your stacks from within the deployment environment. When this type of build is required configure the image-org field to be the name of the org within your target registry and the image-registry field to be the URL of the actual registry the images will be placed in. You can optionally configure the name of the resulting image using the nginx-image-name field. Once run your local docker registry will contain the generated NGINX image which can be pushed to the registry your deployment environment will access. Once deployed the image will serve the repository index files that were created as part of the build.

You can find an example configuration within the example_config folder.

Building the Stack Hub

The stack hub can be built manually or via a CI pipeline such as Travis.

Building the Stack Hub manually

Prerequisites

• Docker 17.05+ or (Podman 1.6.x+ and Buildah 1.9.0+)
• yq 3.x
• jq 1.6+

When building the Stack Hub manually any generated index files will be written to the assets folder at the base directory of the Stack Hub repository.

To build Appsody Stack Hub:

1. Create your Appsody configuration file and place it in the config folder.
2. From the base folder of the repository run the build tool using the command ./scripts/hub_build.sh <config file>. You do not need to specify the path to the file.

Releasing a manually built stack hub

Once you have your generated assets you can host them in a location where they can be accessed by anyone that requires access. If your build was configured to generate an NGINX image then you will need to push it to the image registry it was built for.

Use the ./scripts/hub_deploy.sh command to push the NGINX image to your image registry along with all the referenced stack images. The command will also deploy the stack-hub-index container in your OpenShift cluster. The command requires that you have docker or podman installed and you are logged in to your container registry. The command also requires that you have the oc command installed and that you are logged in to your OpenShift cluster.

Build and release the Stack Hub using Travis CI

repo-tools includes a template configuration file for use with Travis CI here. To use the template follow these steps:

Copy and update the template

1. Copy the template_travis_ci.yml to a temporary location and name it .travis.yml.
2. You need to update the file as follows:
   • Replace <appsody config> with the name of the Appsody configuration file.
   • Replace <git org>/<git repository> with the GitHub organisation and repository name for the Stack Hub, eg, icp4apps/StackHub.

Enable Travis on your repository

Follow the instructions for enabling Travis CI on the Stack Hub repository.

Configuring a PAT to allow Travis to create a Github release

Configure an access token so Travis can access the Stack Hub repository and create releases using the guidance here.

Create a release build

Once Travis is configured the Stack Hub can be released by adding a tag to the source. You can do this through the Git CLI or GitHub website. Details on creating a release can be found here. If you wish to use the git CLI then refer to the following reference, builds will run when the tag is pushed.