K8X Developer Guide

StreamZero K8X aims to make it easy to build event-driven microservices in polyglot environments. As such it gives you complete freedom in selecting the language of your choice.

In order to ’event-enable’ a service K8X requires 3 artefacts to be created.

• The manifest.json file: Which describes your service to the platform.
• The deployment.yaml: A standard kubernetes deployment file which defines your Kubernetes deployment.

Optional Files

• The parameters.json file: Which can be used to define UI Forms attached to the service for manaully trigerred runs. Please read the section on parameters.json to understand the structure of this file.
• The configs.json file: Defines configurations of the service.
• The secrets.json file: Any secrets that are to be associated with the service. These will be injected to the container on launch.

The manifest.json

The following is a sample manifest.json file.

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{
  "name": "k8s_test_job",
  "type": "k8s_job",
  "description": "Deploying k8 job",
  "allow_manual_triggering": true,
  "active": true,
  "trigger_events": ["ferris.apps.minio.file_uploaded"],
  "tags": ["k8s"]
}

The following table describes the attributes of the manifest.json file.

The deployment.yaml file

The following is a sample deployment.yaml file

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apiVersion: batch/v1
kind: Job
metadata:
  name: hello-world
spec:
  template:
    spec:
      containers:
        - name: hello-alpine
          image: frolvlad/alpine-bash
          command: [ "/bin/bash", "-c" ]
          args: [ "echo BEGIN; env; sleep 5; ls -la /usr/bin; echo DONE!" ]
          env:
            - name: SERVICE_PORT
              value: "80"
      restartPolicy: Never

The above is a standard kubernetes job deployment yaml file. As you will note there is nothing special about it. When the above file is processed by K8X it will add the incoming parameters, service secrets and configs into the environment.