Asciidoctor + Spring Boot + K8s

This project shows how work with a containerized Spring Boot service to convert documents with Asciidoctorj.

Table of Contents

• Requirements
• Features
  • Metrics
• Build & Deploy
  • Docker only
  • Kubernetes only
  • Skaffold

Requirements

• Docker

• Kind: to create a simplified local K8s cluster.

• Skaffold: to automate, build, deploy and debugging, with life-reload. Debugging requires IntelliJ + Cloud Code plugin.

Features

Metrics

Skaffold deployment adds metrics server adapted for Kind. Once deployed, you can check the resources used by the pod with

$ kubectl top pods

Build & Deploy

Note deploying in just Docker or local K8s requires the minimal setup, but also require more manual steps. And doesn’t allow for life-reload and code debugging from IntelliJ.

Docker only

To run in plain Docker, build the image and run it.

$ ./gradlew bootBuildImage
$ docker run -it -p8080:8080 asciiboot:0.0.1-SNAPSHOT

To demo it run

curl -X POST -H 'Content-Type: application/json' "http://localhost:8080/asciidoc" -d '{"data":"PSBUaXRsZQo="}' | jq -r '.content' | base64 -d  > file.html

An open file.html

Kubernetes only

1. Start a local Kind cluster

   $ kind create cluster --config kind-config.yaml

2. Build Spring Boot docker image

   $ ./gradlew bootBuildImage

3. Load image into Kind

   $ kind load docker-image asciiboot:0.0.1-SNAPSHOT

4. Deploy in Kind’s K8s cluster

   $ kubectl apply -f manifests/

To validate it:

$ kubectl port-forward service/asciiboot-svc 8080:8080

You should be able to access the Actuator endpoint http://localhost:8080/actuator.

Note

Project contains a modified version of https://github.com/kubernetes-sigs/metrics-server/releases/download/metrics-server-helm-chart-3.8.2/components.yaml adding --kubelet-insecure-tls. Otherwise, metrics-server pod won’t start with error scraper.go:140] "Failed to scrape node" err="Get \"https://172.18.0.2:10250/metrics/resource\": x509: cannot validate certificate for 172.18.0.2 because it doesn't contain any IP SANs" node="kind-21-worker"

Skaffold

Skaffold automates the complete process of building, deploying, port-forwarding and debugging. It also offers life-reload, so that changes in the code ar automatically deployed in the local k8s cluster.

To just run without debugging

$ skaffold dev

You should be able to access the Actuator endpoint http://localhost:8080/actuator.

For debugging install Cloud Code plugin in IntelliJ. Create a Cloud Code: Kubernetes with the Run > Edit Configurations option, and run it as Debug.

You should see the app logs in the IDE console and be able to add breakpoints and debug as any other Java app.