Pipeline as Code Explained in the Simplest Possible Way


Hi there! As a fellow technology geek, I know you‘re always looking for ways to optimize your software development workflows. In this post, I‘ll walk you through Pipeline as Code – a clever approach to automating your CI/CD pipelines by defining them in code.

I‘ll explain what pipelines are, the benefits of the "as code" approach, and how to implement it yourself using Jenkins. Stick with me, and you‘ll be automating builds and deployments like a pro in no time!

What Exactly is a Pipeline in Software Development?

Simply put, a pipeline is an automated process that takes your code changes through several pre-defined steps before releasing them to users. These steps aim to build, test, and deploy your code reliably and efficiently.

For example, a typical pipeline would:

• Get the latest code changes from your version control system
• Run unit and integration tests
• Build binaries or executables
• Package artifacts like containers
• Deploy to staging for testing
• Run security scans
• Promote build to production if all checks pass

Without pipelines, you‘d have to manually execute all these steps. As you can imagine, that‘s super tedious and error-prone! Setting up a pipeline automates the heavy lifting, so developers can focus on just writing code.

According to StackOverflow‘s 2020 survey, over 70% of developers use Continuous Integration (CI) tools like pipelines. And that number is steadily rising as teams recognize the benefits:

Year	% Using CI
2016	63%
2018	69%
2020	71%

It‘s clear that pipelines have become integral to modern software workflows. But manually configuring them via drag-and-drop interfaces can be complex and limiting. This is where "Pipeline as Code" comes in handy!

The Awesomeness of Pipeline as Code

Pipeline as Code allows you to define your entire pipeline in a config file using code. So instead of clicking through a UI, you specify the pipeline stages, actions, conditions etc. in text format as actual code.

This unlocks several advantages:

Consistency

Hardcoding the pipeline as code ensures consistent and repeatable executions every time. There‘s no risk of someone accidentally changing the wrong setting in a UI and breaking things.

Collaboration & Version Control

With Pipeline as Code, multiple team members can collaborate on the pipeline definition file. You can store it in Git/GitHub for version control and change tracking too.

Portability

The pipeline definition file serves as the single source of truth. You can easily reuse it across environments and projects to promote standardization.

Flexibility

Coding pipelines allows for much more flexibility compared to UIs. You can leverage functions, variables, integrations etc. to model complex workflows.

Infrastructure as Code

Pipeline as Code aligns perfectly with infrastructure as code practices like using Terraform. Your application infra and pipelines can both be defined via tidy config files.

Clearly, there are tons of benefits to gain! Now let‘s look at how to actually implement Pipeline as Code using Jenkins, the popular open-source CI/CD automation server.

Creating Pipelines as Code with Jenkins

Jenkins is used by over 80% of CI/CD users thanks to its flexibility and vibrant plugin ecosystem. It‘s the perfect platform for harnessing the power of Pipeline as Code.

Jenkins pipelines are primarily constructed by chaining multiple plugins together. Rather than manually configuring each plugin via the UI, you can define the pipeline in a Jenkinsfile using code.

This Pipeline as Code approach helps you reap all the aforementioned benefits. Now I‘ll walk you through creating and running your own coded pipeline in Jenkins.

Step 1 – Install Jenkins

First, you‘ll need to get Jenkins up and running. You can deploy it on your local machine or a cloud server. Refer to the official docs for detailed installation instructions.

Once Jenkins is installed, access the web UI at http://your-ip:8080 and follow the initial setup prompts.

Step 2 – Create a Sample Pipeline

Log into the Jenkins web UI, then click "New Item" on the homepage to create a new pipeline project. Give your pipeline a name, then select the "Pipeline" project type.


This will take you to the pipeline configuration screen. Here, define your pipeline under the "Pipeline" section using the following Declarative Pipeline syntax:

pipeline {
  agent any 

  stages {
    stage(‘Build‘) {
      steps {
        sh ‘echo "Building.."‘ 
      }
    }

    stage(‘Test‘) {
      steps {
        sh ‘echo "Testing.."‘
      }
    }

    stage(‘Deploy‘) {
      steps {
        sh ‘echo "Deploying.."‘
      } 
    }
  }
}

This defines a simple 3-stage pipeline to build, test, and deploy your code. Each stage runs a single shell command to print a log message.

Step 3 – Run the Pipeline

Save your pipeline configuration and return to the project page. You can now execute the pipeline by clicking "Build Now" in the left sidebar.


This will immediately trigger the pipeline run. You‘ll see each stage executing one after the other.

To view execution logs, click on the build number, then go to "Console Output". You‘ll find the printed messages from each stage here.

And that‘s it! You‘ve now coded and executed your first Jenkins pipeline. Pretty easy, right?

Now let‘s look at more advanced setups.

Creating Pipelines from SCM

Hardcoding pipelines in the Jenkins UI is fine for simple use cases. But for real projects, you‘ll want to store the Pipeline as Code in an external file.

This allows you to put the file under version control in Git/GitHub and make changes more easily.

Here‘s how to configure an external Pipeline as Code file:

1. Create a GitHub repository to store your Jenkinsfile

2. Write your pipeline code in the Jenkinsfile

3. In Jenkins pipeline config, use the "Pipeline script from SCM" definition

4. Provide the Git repo URL containing the Jenkinsfile

Now whenever you run the pipeline, Jenkins will fetch the file from GitHub to extract the latest definition.

This workflow enables you to collaborate on the Jenkinsfile and track changes properly. You can even raise PRs and do code reviews!

Integrating Pipeline as Code with other Tools

A key benefit of Pipeline as Code is integration with other infrastructure-as-code tools. For example, you can use Terraform to spawn servers and databases needed for an environment.

Then your pipeline can deploy the application code onto the resources created by Terraform. You end up with the entire stack defined via neat config files rather than messy GUIs!

You can also integrate Pipeline as Code with:

• Docker – Build images and use containers for pipeline tasks
• Kubernetes – Deploy onto Kubernetes clusters
• Ansible – Provision infrastructure resources
• Lambda – Execute serverless functions

And many more! Basically, the sky‘s the limit when you‘re working with code rather than constraints of a UI.

Reusing Pipelines Across Projects

Thanks to its portability, you can easily reuse a Pipeline as Code file across multiple projects. Just load the Jenkinsfile from a shared repository and override parameters as needed.

This helps you promote standardization and consistency across your software delivery pipelines. No need to re-invent the wheel each time!

Handling Failures Gracefully

Like any code, pipelines will inevitably encounter failures too. Make sure to add error handling, retries, notifications etc. to make your Pipeline as Code resilient.

For example, you can:

• Wrap steps in try/catch blocks to catch exceptions
• Use the retry directive to retry failed steps
• Set up webhook integrations to send failure notifications
• Add timeouts to prevent hung builds

Failures will happen – the key is handling them elegantly so the pipeline keeps running smoothly.

Best Practices for Pipeline as Code

As you start leveraging Pipeline as Code more, keep these best practices in mind:

Keep it DRY

Don‘t Repeat Yourself! Reuse common steps across multiple pipelines to avoid duplication. Extract reusable logic into shared libraries.

Minimize complexity

Keep your pipelines simple and linear. Avoid too many conditional branches and nested logic.

Use declarative over scripted syntax

Declarative pipelines are easier to write, read, and maintain. Use them unless you need advanced scripting capabilities.

Test your pipelines

Unit test your Jenkinsfile code to catch bugs early. You can also mock steps while testing pipelines.

Version control everything

Use Git to store not just app code, but also your Jenkinsfile, libraries, and dependencies.

Monitor pipeline performance

Collect metrics around pipeline duration, failure rates etc. and monitor for improvements.

Automate pipeline creation

Use tools like Jenkins Configuration as Code to automate creating pipelines from config files.

Follow security best practices

Secure your Jenkins instance, use secrets management, and enable role-based access control for pipelines.

Wrapping Up

And that‘s a wrap! I hope this article helped shed some light on what pipelines are and how defining them in code can supercharge your workflows.

Pipeline as Code opens up tons of possibilities – from easier collaboration to integrating with other infrastructure as code tools. The benefits are too good to ignore!

Jenkins makes it really easy to start with coding your pipelines using the Jenkinsfile DSL. You can gradually scale up to advanced setups involving Git, shared libraries, customized DSLs etc.

The key is starting small, expanding slowly based on your needs, and followingPipeline as Code best practices highlighted here. I‘m confident you‘ll be amazed by how much it improves your software delivery processes!

Feel free to hit me up in the comments if you have any other questions. I‘m happy to help fellow tech geeks like yourself master Pipeline as Code. Automate away!