How to build a custom Oracle Container Pipeline ( Wercker ) step to deploy Helm Charts on Kubernetes

If you cannot find a pre-defined step in the Wercker Step store that satisfies your requirement, and if you want these steps defined as custom-code to be consistent and be executed in the same order every single time, you can write your own step.

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  History
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* Oracle completed the acquisition of Wercker in 2017 and added it to their rich CI/CD offerings.
 
* In this article you may find Oracle Container Pipelines being used interchangeably with Wercker!!

If you are new to Wercker, here is some suggested reading

CI-CD simplified with Wercker + Kubernetes on Oracle Cloud Infrastructure

This article relies on the example step for helm that I published on Wercker. Improvements and Contributions welcome!!

Address of Repo

vamsiramakrishnan/step-helm

How to

1. Writing a step on Wercker is no different from using them as a part of your pipeline.

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Concepts
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 A custom Wercker step is a sequence of Wercker steps
 A custom Wercker step is a container published into the Step Store

2. You will need the following

1. A Step Manifest File 
2. A Wercker.yml File
3. A run.sh File

Step manifest

The step manifest contains the following information

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Anatomy of the Step manifest
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1. Name of your step 
2. Version of your step 
3. Summary
4. Configurable Parameters

How does the step manifest file look ?

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GIST
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1) Has Kubeconfig parameters 
2) Has Helm parameters

Wercker.yml File

1. Define your step build like any other build
2. Add a Publish Step in the end. 

How does a Publish Step Look ?

The run.sh file

The run.sh file is the container-entrypoint of the step when it is invoked. Once wercker executes the code in the run.sh file , it moves on to the next step.

How does a Run.Sh Look

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Pseudo-Code
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#!/bin/sh
# Use the Packages defined in Wercker.yml
# Do Something using Property Variables defined in Step Manifest
# Echo Something for the user's benefit
# End of Script

Code:

Import it into Wercker

Building Step== Building Application

* in Wercker :)

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Workflow 
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1) Create New Application
2) Connect it with your SCM in Oracle Developer Cloud Service/ Github/Gitlab
3) Select the repository
4) Add the defined Wercker.yml from repo 
5) Define Pipelines as written in the wercker.yml
6) Trigger Build , by updating 

Go to the Steps store

Voila!! use it!!