Boilerplate

Overview

Service oriented architectures are composed of multiple isolated components that share cross-cutting concerns (CI, Logging, Image Builds, etc). Settling on uniform conventions for these concerns can help streamline the development process. As a system evolves, so too do these conventions. Updating boilerplate often requires manual copy/paste of boilerplate files across many repos.

Boilerplate acts as a source-of-truth for boilerplate code. Using a config file, a service developer specifies which conventions they want for their service. The boilerplate tool reads this config, and copies the appropriate boilerplate files into the service repository.

Why clone files?

Another common method for sharing scripts across repositories is to keep them in one place and run the scripts remotely when needed.

While cloning them into the destination repository takes more space, there are a few advantages.

Some files like .travis.yml _must_ exist inside the target repository. Running that remotely is not an option.
Calling remote scripts is less secure.
Remote scripts adds a dependency on remote services. Copying the files allows users to work offline.
Since all boilerplate files are checked into source code, you can easily view updates to the boilerplate files using your version control system.

Adding boilerplate to a repository

Add export REPOSITORY=<YOUR_REPO_NAME> at the top of the Makefile in your repository (create a Makefile, if needed)
Add the following to your Makefile

.PHONY: update_boilerplate
update_boilerplate:
  @boilerplate/update.sh

Copy the https://github.com/flyteorg/boilerplate/blob/master/boilerplate/update.sh script and paste it to boilerplate/update.sh of your repository. Make it executable with chmod +x boilerplate/update.sh
Add a file boilerplate/update.cfg and configure it with the options below.
Execute make update_boilerplate in the root of your repository to sync the boilerplate.
Execute make update_boilerplate periodically to pull in the latest boilerplate.

Configuration

Boilerplate files are organized into "conventions". Different services require different conventions. For example, python services might require a python Dockerfile, while golang services need a golang Dockerfile. The boilerplate config allows you to opt into only the conventions that suit your needs.

To opt into a convention, configure boilerplate/update.cfg with the conventions that you'd like to opt in to. The convention files live in https://github.com/flyteorg/boilerplate/tree/master/boilerplate and are specified in the format {namespace}/{convention}

For example, to opt-into flyteorg's docker_build and golangci_file conventions, your boilerplate/update.cfg file might look like this:

# Use standard docker build targets
flyteorg/docker_build

# Common linting configuration for golang
flyteorg/golangci_file

below is a full list of available conventions.

flyteorg/docker_build

flyteorg/golang_dockerfile

flyteorg/golangci_file

flyteorg/golang_test_targets

flyteorg/pull_request_template

flyteorg/flyte_golang_compile

Note: some conventions require some minor configurations, the Readme of the convention should inform you of anything else you need to do.

Developing boilerplate

Boilerplate conventions live in the boilerplate directory, and come in the format {{ namespace }}/{{ convention }}. This directory should contain all boilerplate files, along with two special files.

Readme.rst

Every boilerplate convention should come with a Readme.rst that explains:

All functionality provided by the boilerplate files.
How to use the the boilerplate.

All boilerplate changes should update the Readme.rst to explain the changes. This ensures that a developer syncing boilerplate updates will understand the changes.

Update.sh

Some boilerplate files require small changes beyond the default file cloning. For example, the travis.yml file needs to exist in the root of your repo (not in the boilerplate directory where it's cloned by default). After cloning, the update.sh script for the convention will run. The convention developer can use that script to copy the .travis.yml file from the boilerplate directory into the root of the repository.

veggiemonk / boilerplate