Jenkins pipeline Continuous Integration - jenkins

I have 20-30 projects that I am working on with their own git repos, each repo have several branches not dependent on other projects. I am looking if there's some way to come up with Jenkins Pipeline to accommodate all the projects with CI/CD ecosystem. OR do I need to create separate pipeline for each repo.
Is there a way I can use one Jenkins-file into all these projects.
how do you share data between pipelines if module 3 is depenendent on data coming from Module1&2.
do I need to create 30 hooks/tokens if I have 30 projects?
I was able to create dependent build triggers between the very first three such that if A & B build then C will build using the SCM polling option and build triggers.
Thanks in advance. Appreciate any help, feedback or suggestions.

You can use shared libraries in Jenkins pipelines. It is a fairly involved process requiring writing libraries in groovy.
As Pipeline is adopted for more and more projects in an organization,
common patterns are likely to emerge. Oftentimes it is useful to share
parts of Pipelines between various projects to reduce redundancies and
keep code "DRY".
Pipeline has support for creating "Shared Libraries" which can be
defined in external source control repositories and loaded into
existing Pipelines.

Related

Is it possible to have a common repository for multiple pipeline jobs?

I have 11 jobs running on the Jenkins master node, all of which have a very similar pipeline setup. For now I have integrated each job with its very own Jenkinsfile that specifies the stages within the job and all of them build just fine. But, wouldn't it be better to have a single repo that has some files (preferably a single Jenkinsfile and some libraries) required to run all the jobs that have similar pipeline structure with a few changes that can be taken care of with a work around?
If there is a way to accomplish this, please let me know.
Use a Shared Library to define common functionality. Your 11 Jenkinsfiles can then be as small as only a single call to the function implementing the pipeline.
Besides using a Shared Library, you can create a groovy file with common functionality and call its methods via load().
Documentation
and example. This is an easier approach, but in the future with the increasing complexity of pipelines, this may impose some limitations.

Is there a trick to debug shared groovy libraries without pushing?

I'm adding to, and maintaining, groovy files to build a set of repositories - previously they were built with freestyle Jenkins jobs. I support some code in shared libraries and to be honest (mainly for DRY reasons) I want to do that more.
However, the only way I know how to test and debug those library files is to push the changes on a git branch. I know about the "replay" trick to test the main Jenkins file. Is there some approach I've missed to do something similar for library code?
If you set up a job to load the shared library instead of relying on a globally set up shared library (you can have both going, for this particular job), then it is possible to hit "replay" and have all your shared library steps show up as editable files.
This can be helpful in iterative development without a million commits.
EDIT: Here's how that looks on an Organization job in Jenkins.
There is the 3rd party Jenkins Pipeline Unit testing framework.
While it does not yet cover all features of pipeline, it is well documented and maintained so that I would consider starting using it (once I revisit our Jenkins setup).

How can I share source code across many nodes in a Jenkins pipeline job?

I have a build that's currently using the old build flow plugin that I'm trying to convert to pipeline.
This build can be massively parallelized (many units of work can run on many different nodes) but we only want to extract the source code once at the beginning, preferably with the Pipeline script from SCM option. I'm at a loss to understand how I can share the source extract (which apparently is on the master) with all of the "downstream" nodes that will be used by the pipeline script.
For build flow we extracted to a well-known location on a shared file system and all of the downstream jobs invoked by the flow were passed (or could derive) that location. That always felt icky & I was hoping that pipeline would have solved this problem but I can't find anything to suggest that it has. What am I missing?
I believe the official recommendation for this is to make bundles of the source and then use "stash" and "unstash" to make them available to deeper steps of your pipeline script.
See https://www.cloudbees.com/blog/parallelism-and-distributed-builds-jenkins
Keep in mind that this doesn't do anything to help with line-endings. If you have builds that span OSs with different line endings you either need to make OS-specific stashes, or just checkout to a safe label in each downstream step.
After further research it seems like the External Workspace Manager Plugin does what I'm looking for.

Jenkins with many solutions in one repository

I am trying to setup Jenkins to automate a build. We have one enormous repository with approximately 100 solution files. To build this repository we have a build program which finds all the solutions and builds in a specified order.
I would like to change that to use Jenkins. Is there a way to setup msbuild and specify a build order for all of these solution files?
p.s. I am trying to avoid creating one mammoth solution file which contains all of the projects.
If in fact all of your projects use ProjectReferences to other VS projects, you should be able to use MSBuild to extract all those references via the ResolveProjectReferences MSBuild task. You can then build an MSBuild script build those dependent projects in order. There's a pretty good example of this here. The example given there goes so far as constructing a specialized MSBuild task that builds a dependency graph, which I must say is pretty cool.

Problems with Jenkins Build pipeline and parallel jobs

Background
I am using Jenkins with the Build Pipeline plugin to build some fairly complicated projects that require multiple compilation steps:
Build source RPM.
Build binary RPM (this is performed twice, once for each platform).
Deploy to YUM repository.
My strategy for solving build requirements involves splitting the common work into parameterized jobs that can be reused across projects and branches, with each job representing one stage in the pipeline. Each stage is triggered with parameters, and build artifacts passed along to the next job in the pipeline. However, I'm having some trouble with this strategy, and could really use some tips on how to go about solving this problem in the most elegant and flexible way possible.
To be more specific, there are two common libraries, which are shared by other projects (but not all projects). The libraries are built differently from the dependent projects, but it should not be necessary to specify in Jenkins what the dependent projects are.
There are multiple branches, the master branch (rebuilt nightly), the develop branch (polled for changes), feature branches (also polled), and release branches (polled, but built for release). The branches are built the same way across multiple projects.
We create multiple repositories every month, and whilst it is feasible to expect a little setup for a new project, generally we want this to be as simple and automated as possible.
The Problems
I have many projects with multiple branches, and I do not wish to build all branches or even all projects in the same way. Because most of the build steps are similar I can turn these common steps into parameterized build jobs, and get each job to trigger the next in the chain, passing parameters and build artifacts along the chain. However, this falls apart if one of the steps needs to be skipped, because I don't know of a way to conditionally skip a build step. This implies I would need to copy the build jobs so that I can customise them for each pipeline, resulting in a very large number of build jobs. I could use a combination of plugins to create a job generator (eg. dsl flow, dsl job, etc), and hide as much as possible from the users, but what's the most elegant Jenkins solution to this? Are there any plugins, or examples that I might have missed? What's your experience of doing this?
Because step 2 can be split into two jobs that can be run in parallel, this introduces a complexity that is causing me problems with my pipeline. My first attempt would trigger a parameterized build job twice with different parameters, and then join the jobs afterwards using the join plugin, but it was beginning to look like it would be complicated to copy in the build artifacts from the two upstream jobs. This is significant, because I need the build artifacts from both jobs for stage 3. What's the most elegant solution to join parallel jobs and copy artifacts from them all? Are there any examples that I might have missed?
I need to combine test results generated from both of the jobs in stage 2, and copy them to the job that triggers the build. What's the best way to handle this?
I'm happy to read articles, presentations, technical articles, reference documentation, write scripts and whatever else necessary to make this work nicely, but I'm not a Jenkins expert. If anyone can give me some advice on these 3 problems then that would be helpful. Additionally, I would appreciate any constructive advice on how to get the best out of pipeline CI builds in Jenkins, if relevant.
For the first point, the Job Generator plugin I wrote has been developed to address this use case. You can find more info on the wiki page of Job Generator.
There is also the same type of plugin with a different approach (job generator as a build step), it is called Jobcopy Builder.
The other approaches you mentioned require some kind of DSL and can be a good choice too.

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