Jenkins scripted pipeline or declarative pipeline

Nayana Adassuriya picture Nayana Adassuriya · Apr 19, 2017 · Viewed 64.5k times · Source

I'm trying to convert my old style project base workflow to a pipeline based on Jenkins. While going through docs I found there are two different syntaxes named scripted and declarative. Such as the Jenkins web declarative syntax release recently (end of 2016). Although there is a new syntax release Jenkins still supports scripted syntax as well.

Now, I'm not sure in which situation each of these two types would be a best match. So will declarative be the future of the Jenkins pipeline?

Anyone who can share some thoughts about these two syntax types.

Answer

Nayana Adassuriya picture Nayana Adassuriya · Oct 7, 2017

When Jenkins Pipeline was first created, Groovy was selected as the foundation. Jenkins has long shipped with an embedded Groovy engine to provide advanced scripting capabilities for admins and users alike. Additionally, the implementors of Jenkins Pipeline found Groovy to be a solid foundation upon which to build what is now referred to as the "Scripted Pipeline" DSL.

As it is a fully featured programming environment, Scripted Pipeline offers a tremendous amount of flexibility and extensibility to Jenkins users. The Groovy learning-curve isn’t typically desirable for all members of a given team, so Declarative Pipeline was created to offer a simpler and more opinionated syntax for authoring Jenkins Pipeline.

The two are both fundamentally the same Pipeline sub-system underneath. They are both durable implementations of "Pipeline as code." They are both able to use steps built into Pipeline or provided by plugins. Both are able to utilize Shared Libraries

Where they differ however is in syntax and flexibility. Declarative limits what is available to the user with a more strict and pre-defined structure, making it an ideal choice for simpler continuous delivery pipelines. Scripted provides very few limits, insofar that the only limits on structure and syntax tend to be defined by Groovy itself, rather than any Pipeline-specific systems, making it an ideal choice for power-users and those with more complex requirements. As the name implies, Declarative Pipeline encourages a declarative programming model. Whereas Scripted Pipelines follow a more imperative programming model.

Copied from https://jenkins.io/doc/book/pipeline/syntax/#compare