Building two git repositories with Jenkins - jenkins

Question

I need to build two Maven projects which are available on Github. The first project produces a library which is needed by the second.
What is the recommended option to do it in Jenkins ?
Create a shell script which checkout and build both projects (in the correct order).
Use a pipeline ?
If you could provide any example/ relevant link that would be great. Thanks

Answer 1

You can achieve using 2 (upto my knowledge) options. Lets consider project A which builds libraries and project B is the dependent. I described below two options by considering two constraints.
Project B should be built whenever Project A is built
Project B can also be built alone if there is only changes with Project B but not with A
Option 1:
You have to create two "Maven Build jobs" for Project A & B. In Project B, you have to specify "Build whenever a SNAPSHOT dependency is built" under "Build Triggers".
This only applies when project B pom.xml has dependency of Project A built artifacts and the artifacts are SNAPSHOT. Below is the image of the same.
Options 2: You can create two Freestyle job for both Project A & B. Define Project B is downstream for Project A ( It can also be done vice versa ) using "Build Other Projects" under "Post-Build Options" of Project A.
And you can copy artifacts from Project A to Project B using Copy Artifact Plugin
Exception: Ideally the above step is not necessary, if your Project A artifacts are installed on $HOME/.m2/repository and Project B dependency defined in pom.xml (or) both project A & B are using Private Maven Repository option.
Assumption: I hope using single pipeline, it will be hard to manage this scenario. Though I expect somebody else will write with pipeline example to enlighten me as well :)

Answer 2

You can achieve this using Jenkins pipeline jobs.
First we need to create a folder for project A and in side that you can download the source code using GIT plugin and you can build the solution.
And create another folder and inside your download the source code of another project and you can build the second solution.
eg:
node{
stage('first project'){
dir('project1'){
git branch: '<Branch>', changelog: false, poll: false, url: '<First Repo URL>'
sh 'mvn clean install'
}
}
stage('second project'){
dir('project2'){
git branch: '<Branch>', changelog: false, poll: false, url: '<Second Repo URL>'
sh 'mvn clean install'
}
}
}

Answer 3

Sharing a method I used for building two changes.
Just add "Depends: xxxxxxx" before the Change-Id in your git commit message:
Depends: fe1a5effxxxxxxxxxxxxxxxxb8xxxx
Change-Id: Ig43j5cxxxxxxxxxxxxxxxxxxxxxxxxxxxx