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Development Guide

Prerequisites

Tools

  • make
  • go version v1.13+.
  • docker version 17.03+.

Other tools

This repo uses other tools for development, building and testing. These tools are installed with make install-tools:

  • controller-gen
  • golangci-lint
  • mockgen
  • conversion-gen
  • kubebuilder
  • kustomize
  • addlicense
  • misspell
  • kind

Cluster

  • Access to a Kubernetes v1.11.3+ cluster.

Development

Fork and Clone

Fork Application Repo. Then clone your fork locally.

mkdir -p $GOPATH/src/sigs.k8s.io
cd $GOPATH/src/sigs.k8s.io

GITHUBID=<githubid>
git clone git@github.com:${GITHUBID}/application.git $GOPATH/src/sigs.k8s.io/application

Cluster access

For running e2e tests and development testing you need access to a cluster. You could create a cluster with your cloud provider and ensure the kubeconfig points to the cluster.

Local cluster

For local testing you could create a kind.

# this created a kind cluster and updates kubeconfig to point to it
make e2e-setup

Building the controller binary

# make or make all will build
make

# individual run make targets
#
# generate code
make generate

# create manifests
make manifests

# Inject license header to all generated files
make license

# building the kube-app-manager
make bin/kube-app-manager

Running tests

After making changes use these targets to test locally.

unit tests
# running unitests
make test
e2e tests
# running e2e tests

# If your kubeconfig points to your test cluster skip this step
# This will create a kind cluster for testing
make e2e-setup

# run e2e tests
make e2e-test

# Tear down kind cluster
make e2e-cleanup

Building controller docker

To build the controller into an image named image use the following command.

NOTE: CONTROLLER_IMG is optional. The default value is gcr.io/$(shell gcloud config get-value project)/kube-app-manager

make docker-build CONTROLLER_IMG=<image>

To push the controller image, run:

make docker-push CONTROLLER_IMG=<image>

Installing CRD in the cluster

Once kubeconfig is setup with a cluster.

make install

Deploying the controller in cluster

  • This will install the controller into the application-system namespace and with the default RBAC permissions.
  • It will also install the Application CRD.
  • Ensure the docker image is built and pushed first.
make deploy CONTROLLER_IMG=<image>

Using the Application CRD

The application CRD can be used both via manifests and programmatically.

Manifests

The docs directory contains an example manifest that shows how to you can integrate the Application CRD with a WordPress deployment.

The Application object uses StatefulSets and Services. It also contains some other relevant metadata describing wordpress application. Notice that each Service and StatefulSet is labeled such that Application's Selector matches the labels. The additional labels on the Applications components come from the recommended application labels and annotations.

# Deploying the example

make deploy-wordpress
kubectl get application

# cleanup
make undeploy-wordpress

Programmatically

Kubebuilder provides a client to get, create, update and delete resources and this also works for application resources. This is documented in the kubebuilder book: https://book.kubebuilder.io/

Create a client:

kubeClient, err := client.New(config)

Get an application resource:

object := &applicationsv1beta1.Application{}
objectKey := types.NamespacedName{
    Namespace: "namespace",
    Name: "name",
}
err = kubeClient.Get(context.TODO(), objectKey, object)

Create a new application resource:

app := &applicationsv1beta1.Application{
	...
}
err = kubeClient.Create(context.TODO(), app)