What is Pipeline?

 

A pipeline in a Software Engineering team is a set of automated processes that allow Developers and DevOps professionals to reliably and efficiently compile, build and deploy their code to their production compute platforms. There is no hard and fast rule stating what a pipeline should like like and the tools it must utilise, however the most common components of a pipeline are; build automation/continuous integration, test automation, and deployment automation

In Jenkins, a pipeline is a group of events or jobs which are interlinked with one another in a sequence

In layman’s terms, a DevOps pipeline is a series of automated steps that help take your code (the instructions for your computer programs) from being written by a developer to being a working application that users can interact with. It's like a factory assembly line for software.

Here's a simple analogy:

Imagine you're baking a cake. The steps might include:

1. Gather Ingredients: Get flour, eggs, sugar, butter, etc.
2. Mix Ingredients: Combine everything to make the batter.
3. Bake the Cake: Put the batter in the oven and bake.
4. Decorate the Cake: Once the cake is baked, add frosting and decorations.

Similarly, a DevOps pipeline has steps to take your code through:

1. Code: Write the code.
2. Build: Combine the code into a format that can be run.
3. Test: Check the code to make sure it works correctly.
4. Deploy: Put the code on a server where users can access it.
5. Monitor: Keep an eye on the application to ensure it's running smoothly.

Each of these steps is automated, meaning it happens on its own once set up, making the process faster and less prone to errors. This helps developers deliver updates and new features to users quickly and reliably.

What is a JenkinsFile?

Jenkins pipelines can be defined using a text file called JenkinsFile. You can implement pipeline as code using JenkinsFile, and this can be defined by using a domain specific language (DSL). With JenkinsFile, you can write the steps needed for running a Jenkins pipeline.

Declarative versus Scripted pipeline syntax:

There are two types of syntax used for defining your JenkinsFile.

1.                      Declarative

2.                      Scripted

Declarative:

Declarative pipeline syntax offers an easy way to create pipelines. It contains a predefined hierarchy to create Jenkins pipelines. It gives you the ability to control all aspects of a pipeline execution in a simple, straight-forward manner.

Scripted:

Scripted Jenkins pipeline runs on the Jenkins master with the help of a lightweight executor. It uses very few resources to translate the pipeline into atomic commands. Both declarative and scripted syntax are different from each other and are defined totally differently.

Why Use Jenkin's Pipeline?

Jenkins is an open continuous integration server which has the ability to support the automation of software development processes. You can create multiple automation jobs with the help of use cases, and run them as a Jenkins pipeline.

Term	Description
Pipeline	The pipeline is a set of instructions given in the form of code for continuous delivery and consists of instructions needed for the entire build process. With pipeline, you can build, test, and deliver the application.
Node	The machine on which Jenkins runs is called a node. A node block is mainly used in scripted pipeline syntax.
Stage	A stage block contains a series of steps in a pipeline. That is, the build, test, and deploy processes all come together in a stage. Generally, a stage block is used to visualize the Jenkins pipeline process.
Step	A step is nothing but a single task that executes a specific process at a defined time. A pipeline involves a series of steps.