Jenkins: Pipeline

• A pipeline is a collection of steps or jobs which are interlinked with one another in a sequence.

• Jenkins supports different plugins which help to implement CI/CD pipelines into Jenkins i.e., Git plugin, Build Pipeline plugin, Jenkins Maven plugin, Full Stage View…etc.

• A pipeline can be written using two types of syntax- Scripted and Declarative.

Scripted Pipeline-

• This is the original pipeline syntax for Jenkins, which is based on the Groovy scripting Language (old method to create the pipeline).

• It provides a lot of flexibility and control over the workflow but it can be more complex.

• Syntax-

  

• Hands-On-

  Let’s create a pipeline with a simple syntax and check for the pipeline “Full Stage View“-

  

Declarative Pipeline-

• It’s a simpler approach or It’s a more recent addition to Jenkins and provides a more structured and simpler syntax for defining the pipelines.

• The code is simplified because declarative syntax is more limited. You won’t be able to inject code into the pipelines whenever you want.

• This type of pipeline is not worth it while working on a complex logic.

• Syntax-

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Hands-On -

Let’s create a pipeline with a simple syntax and check for the pipeline “Full Stage View“-

Scripted vs Declarative Pipeline-

1. Pipeline Code Validation-

• Scripted Pipeline- Code Validation happens during the pipeline execution, which means at the very end stage only we will get to know about the errors or issues.

  • Example- We are deleting the echo message and then we will check in the full stage view after build-

    

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  • Declarative Pipeline- Code Validation happens when the pipeline is loaded into the Jenkins, i.e., before running the pipeline.

    • Example-

      

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2. Restart From Stage-

• Scripted Pipeline- Restarting from a specific stage is not directly supported, we need to restart it from the beginning and it will consume more time as previously executed stages need to be repeated.

• Declarative Pipeline- Restarting from a specific stage is supported and by this we can save time and resources by skipping already completed stages.

  • Example-

    

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3. Skipping Stage-

• Scripted Pipeline- All stages will be executed sequentially, there is no built-in support for skipping stages.

• Declarative Pipeline- Supports skipping stages using the “when“ directive and allows conditional skipping of stages based on specified conditions.

Source

Happy Learning!! 😁