- [Instructor] Okay, welcome back! In this demonstration, I'm going to walk you through the process of connecting downstream and upstream build projects together. 

So what examples are there that might motivate us to do this? Well, consider a build project where you're building Library One, and then you also have a second library called Library Two. Now, Library Two has a dependency on Library One. Now, if you've rebuilt Library One, then the requirement would be that Library Two needs to be rebuilt to take into account any modifications made in Library One. And so this is a good example of connecting build projects together. So we'll jump into this. 

So, let's log back in. Recalling from our previous demonstration, we select BuildJob1. So what we'll do now is we'll click on New Item, and we'll create BuildJob2. It will also be a freestyle project, and we click on OK. We'll click on the Build tab, and again, we'll add a simple shell script for the build job. So here we'll simply echo out BuildJob2. We'll click Apply, and Save. We'll click the Build Now, just to make sure there that executes successfully, which it has, we click on build job number one, look at the console output and, as expected, we have a success for it. 

Okay, so let's go back to the Jenkins homepage. So we have BuildJob1 and BuildJob2. Now what we wanna do is configure BuildJob1 to trigger BuildJob2 anytime that it executes successfully. So here we select Post-build Actions, and we'll click on the add post-build action drop-down. This time we'll select build other projects, and we'll enter the project name that we want to build, which will be BuildJob2. We'll trigger BuildJob2 only if this current BuildJob1 is stable. Notice that we can do multiple projects as well, but for now we'll stick with just BuildJob2. We'll click Apply, and we'll click Save. 

Now, we'll store within BuildJob1, and what we'll do now is we'll click the Build Now link. Okay, build number eight has successfully completed, and if we go back to the dashboard, if we go into BuildJob2, you'll notice now that a second build job has also been executed for it. And this is a result of BuildJob1 running and completing successfully. If we go back to the dashboard, and on BuildJob1, we trigger another build, we go back into BuildJob2, again, you see a third build is being executed. Now, within each build job, we can see the upstream or downstream projects. In the case of BuildJob2, it has an upstream project called BuildJob1. Clicking on BuildJob1, you can see that it has a downstream project, which is BuildJob2. 

So in summary, this demonstrates how you can chain together build jobs. And depending on where in the chain the particular build job is, it will either be considered a downstream build project or an upstream build project.