TDD for jenkins pipelines

© 2018 All Rights Reserved. !2
*http://www.wyeside.co.uk
WHOAMI
#DevOps Engineer => #Solution Architect
#Core of DevOps engineer team
#CI/CD #Docker #K8s
#MakeLifeEasierForDevelopers
🐦 @ferratello
🌎 http://about.me/mauroferratello

How do I feel now
https://commons.wikimedia.org/wiki/File:Spinecheek.jpg

Once upon a time...
https://pixabay.com/en/castle-fairy-tales-nature-water-2064013/
... around 2011/2012

It was a mess
• Not real CI
• build jobs made by brave volunteers
• nobody cares of the build status
https://pixabay.com/en/anarchy-political-social-rebellion-32917/¬

Monolithic
application
• 2 or 3 releases/year
• deploy duration: 2 or 3 months
• n parallel branches
• urgent features straight in prod.
https://upload.wikimedia.org/wikipedia/commons/thumb/2/2f/095-pile-of-poo.svg/512px-095-pile-of-poo.svg.png

Let's go to
microservices
https://upload.wikimedia.org/wikipedia/commons/thumb/2/2f/095-pile-of-poo.svg/512px-095-pile-of-poo.svg.png

DevOps Anarchy
many different way to deploy something
https://pixabay.com/en/puzzle-unfinished-mess-unresolved-55879/

we need a superhero!
http://pngimg.com/uploads/lego/lego_PNG29.png
... Yes, it's me 😬

Goal #1
One job to rule them all
https://www.flickr.com/photos/mk1971/1348204498

Same tech stack
• Same server configuration
• Same application configuration
way
https://commons.wikimedia.org/wiki/File:Gorilla-server.svg

D'oh!
Cannot access directly to
production server
http://pngimg.com/uploads/simpsons/simpsons_PNG94.png

Workaround: dependency inversion
• Copy artifact on server
• Copy/change configuration o the
remote server
• execute remotely commands
Do Delegate
• Tell the server to download artifacts
from trusted repository
• Tell the server to upgrade
configuration from trusted repo
• Tell the server to deploy itself the
new artifact
vs

We supposed
we solved all our problems
http://www.thebluediamondgallery.com/wooden-tile/h/happiness.html

New needs
Custom request to deploy a JAR
not WAR
https://it.m.wikipedia.org/wiki/File:Question-mark-blackandwhite.png

D'oh!
Regression Bugs!

How to prevent?
• We need a way to test our code
• We need to run the test automatically after any change

Why I have to test my final pipeline script?
• It's like test code only with e2e tests
• We have to repeat the same tests for all the pipelines

Need #2
• Remove duplication
• Make pipelines simple for devs but robust at the same time

#Global shared libraries!
https://www.pexels.com/photo/library-university-books-students-12064/

Why?
• It's a way to avoid reinventing the wheel.
• They allow you to define your own library to share with all the pipeline scripts you use
• They allow you to reuse your code
• But most of all... you can test your libraries!
• https://jenkins.io/doc/book/pipeline/shared-libraries/

How to use them?
• The "modern" way
• Libraries loaded dynamically
• Include only what you need 
• I'm showing you this way 😉
@Libraryworkflow-libs
• The "old" way
• Libraries on the jenkins file system
• Loaded at jenkins startup
(sometimes with trouble)
• we followed this way 🤠

Structure

Step#1
• Move shared code into dedicated function (/vars)

D'oh!
We can't test it locally

Let's do OOP
Groovy objects

Because we are "Clean Coders"
• SOLID principles
• Design
• Dependency injection
• etc...
• ...and TDD!

Start easy
• A simple class to encode
parameters

...and its unit tests

That's so easy
But what about something more complicated?
And that needs jenkins pipeline steps?
https://jenkins.io/doc/pipeline/steps/

D'oh!
• We can't access it inside
groovy classes
• We can't test it locally

Reference
Pass "steps" as a reference in
constructor parameters
https://en.wikipedia.org/wiki/File:VisualEditor_-_Icon_-_add-reference.svg

Example
• HttpClient
• "jenkins" is the reference

Mock Objects
Let's mock as if there's no tomorrow
https://pixabay.com/en/fake-forgery-counterfeit-fraud-1726362/

Example
• HttpClientTest
• "jenkins" is mocked
thanks to groovy
features

Let's try it in
production...
• It's broken, due to an
unexpected behavior!
• pipelines broken for everyone!
• D'oh!

We need Integration Test!
• They must be able to run
• LOCALLY
• on JENKINS

Example of IntegrationTest on HTTP Client

Locally we used Fake implementations
• We pass a fake instance of "steps" object to the test
• The fake object return the expected value so the test can pass even locally
• Alternatively the fake object can perform the same action with different
implementation (eg HttpRequest vs HttpURLConnection)

Run on Jenkins
• in the pipeline the real jenkins "steps" is passed as a constructor parameter of the
test and real action is performed
• eg. for HTTPClient the real HttpRequest is used

Pipeline with UT and IT running

What we have seen:
✔ How to write simple unit tests
✔ How to write complex tests mocking jenkins steps
✔ How to write integration tests
✔ How to run unit test locally and on jenkins
✔ How to run integration test locally and on jenkins
.
.
.
✔ There's no silver bullet. Sometimes you have to accept compromises

References
• My sample repository:  
https://gitlab.com/Ferratello/jenkins-shared-libraries/
• Jenkins Global Shared Libraries : 
https://jenkins.io/doc/book/pipeline/shared-libraries/
• Jenkins instance used to execute tests: 
http://localhost:8080/
• I'm kidding 😬 but you can have your own simply running: 
docker run -p 8080:8080 -v /local/path/for/jenkins_home:/var/jenkins_home jenkins/jenkins:alpine

TDD for jenkins pipelines

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to TDD for jenkins pipelines

Similar to TDD for jenkins pipelines (20)

Recently uploaded

Recently uploaded (20)

TDD for jenkins pipelines