monorepo-deploy-actions

This is a set of GitHub Actions to deploy microservices in a mono-repository (monorepo).

Motivation

TODO

Concept

Structure of monorepo

In Quipper, our monorepo contains a set of microservices with Kubernetes manifests, for example,

monorepo
├── backend
|   ├── sources...
|   └── kubernetes
|       ├── base
|       └── overlays
|           ├── develop
|           |   └── kustomization.yaml
|           └── staging
|               └── kustomization.yaml
├── frontend
|   ├── sources...
|   └── kubernetes
|       └── overlays
|           └── ...
└── ...

We adopt this strcuture for the following advantages:

• An owner of microservice (i.e. product team) has strong ownership for both application and manifest
• We can change both application and manifest in a pull request

We deploy a set of services from a branch to a namespace. For example,

• When develop branch is pushed,
  • Build a Docker image from develop branch
  • Run kustomize build against develop overlay
  • Deploy to develop namespace
• When a pull request is created,
  • Build a Docker image from head branch
  • Run kustomize build against staging overlay
  • Deploy to an ephemeral namespace like pr-12345

Consequently, a structure of monorepo is like below.

monorepo
└── ${service}
    └── kubernetes
        └── overlays
            └── ${overlay}
                └── kustomization.yaml

Structure of Argo CD Applications

We adopt App of Apps pattern of Argo CD for deployment hierarchy. To deploy multiple microservices (which are built from an overlay) to a namespace, we creates the following applications into Argo CD:

${source-repository-name}  (Application)
└── ${overlay}  (Application)
    └── ${namespace}  (Application)
        └── ${service}  (Application)

Here are the definitions of words.

Name	Description	Example
source-repository-name	name of source repository	monorepo
overlay	name of overlay to build with Kustomize	staging
namespace	namespace to deploy into a cluster	pr-12345
service	name of microservice	backend or frontend

Destination repository

We stores generated manifests into a repository. Argo CD syncs between the repository and cluster.

main branch of the repository contains Application manifests.

destination-repository  (branch: main)
└── ${source-repository-name}
    └── ${overlay}
        └── ${namespace}.yaml  (Application)

A namespace branch contains a set of generated manifest and Application manifest per a service.

destination-repository  (branch: ns/${source-repository}/${overlay}/${namespace})
├── applications
|   └── ${namespace}--${service}.yaml  (Application)
└── services
    └── ${service}
        └── generated.yaml

Development

Node.js and pnpm is required.

brew install node@20
corepack enable pnpm

Release workflow

When a pull request is merged into main branch, a new minor release is created by GitHub Actions. See https://github.com/int128/release-typescript-action for details.

Dependency update

You can enable Renovate to update the dependencies. See https://github.com/int128/typescript-action-renovate-config for details.