In the first post of the series, I talked about what continuous integration is and why you should use it. In this post, I’m going to start by describing what Jenkins is and the steps on how to set it up. Next, we’ll add plugins that will allow you to checkout a repository using Mercurial and to build the project using MSBuild. Finally, we’ll configure a means of notifying you if a build fails by using Gmail.
What Is Jenkins?
Jenkins is a stand-alone continuous integration server that listens to a repository for changes. Once Jenkins sees that a check-in has occurred, it begins to perform a series of steps (called a build). These steps can range from building the solution, running tests, deploying databases, copying artifacts, building installers, creating documentation, or deploying software. Jenkins (and it’s predecessor Hudson) have been around for quite a while now and is one of most commonly used CI servers around. One of the reasons I like Jenkins is that I can set it up on a virtual machine and have it running all the time.
How Do I Setup Jenkins?
The Jenkins server is pretty easy to setup. First, we will need to install the Java Runtime Environment (JRE). After installing the JRE, we will install the Jenkins tool. Once Jenkins is up and running we can proceed to install the plugins and start configuring the Jenkins instance.
Download and Install Java
The only dependency you need to run Jenkins is to install the Java JRE. You can download the latest run time from here. During the install, choose the defaults. After the JRE installs, you’re ready to install Jenkins.
Download and install Jenkins
After downloading and installing the JRE, you will need to install the Jenkins server by going to http://jenkins-ci.org/ and choosing the appropriate download option for your system. After downloading, extract the zip folder and run the setup application. After the install you will now have a Jenkins service running at http://localhost:8080.
Now that we have Jenkins up and running, it’s time to extend Jenkins by installing plugins that will allow us checkout out our source code and build the solution. These plugins make Jenkins very powerful since you can install which ones you need for your jobs. The following sections will detail how to install plugins in general and how to install the MSBuild and Mercurial plugins in detail.
As mentioned earlier, before we can create a job, we need to install the plugins required for said job. At the bare minimum for our example, you will need to install a plugin for your source control and a plugin for compilation.
In order to install a plugin, on the Jenkins machine, navigate to http://localhost:8080 and go to Manage Jenkins -> Manage Plugins (next to the green puzzle piece).
On this screen, you can see which plugins have updates, which plugins you have installed, and which plugins that are available for download. When adding/removing plugins, you will come to this area often.
Now on the Plugins screen, navigate to the Available Plugins tab and using the filter box, search for the Mercurial plugin and select the option shown:
After selecting Mercurial, it’s time to install MSBuild. In the filter box, type MSBuild and select the option below:
After selecting the MSBuild plugin, it’s time to install the plugins by clicking on the Download now and install after restart button. After clicking the button, click the check box and then Jenkins will restart.
After Jenkins restarts, it’s time to configure the plugins to be able to use them in a job.
Configuring System-Wide Properties of Jenkins
At this point, we have Jenkins up and running and our plugins installed. However, we need to configure these plugins so we can use them in a job. To configure plugins, we need to configure the system-wide settings of Jenkins. To get to this menu, navigate to http://localhost:8080 and click Manage Jenkins -> Configure System.
On this screen, every plugin installed with Jenkins is listed with some global settings for that plugin. In general, a plugin will need to know where the tool it uses resides at. For example, the Mercurial plugin needs to know where the mercurial executable is on the machine.
Configuring the Mercurial Plugin
Before you can configure the plugin, you will need to have Mercurial installed (Need to install Mercurial?, look no further). Not sure if Mercurial is installed? Open up a command prompt and enter “hg version”. If Mercurial has been installed, then you should see the version of Mercurial installed, otherwise, you probably don’t have it installed.
To configure the plugin, navigate to the Configure System screen and look for the Mercurial section. After finding the section, click the Mercurial Installations button.
After clicking this button, there will be some options to configure. For this setup, the most important ones are Name, Installation Directory, and Executable.
The Name field is what’s shown when selecting the source control for a build, so make sure it’s descriptive. I usually include the version number as part of the name.
The Installation Directory field is where the Mercurial executable is located. If you Mercurial is part of your path, then you don’t need to specify this, otherwise, just enter the directory that the executable is located.
The Executable field is where you specify what the name of your mercurial executable is. The majority of the time, hg.exe is the name you want, so shouldn’t have to change this.
Configuring the MSBuild plugin is similar to configuring the Mercurial plugin. As before, navigate to the Configure System screen and find the MSBuild section. From here, find the MSBuild section and click the MSBuild Installations button.
After clicking this button, there will be some options to configure. For this setup, the most important ones are Name, Path To MSBuild, and Default Parameters.
The Name field is what’s shown when selecting the compiler for a build, so make sure it’s descriptive. I usually include the version number as part of the name.
The Path To MSBuild field is where the MSBuild executable is located. By clicking the ? button, it will tell you what the default path is for MSBuild. Since the MSBuild is included in every Windows machine, this location should be the one to use. Make sure you add msbuild.exe to the end of the path (even though you will get a warning message, you need to provide the full path).
The Default Parameters field is where you can specify additional command switches to MSBuild. This can be helpful if you have a certain configuration you want used when building (like build in release mode). It’s not necessary to add any switches for MSBuild to work out of the box, so I’m omitting it here.
Configuring Email Notifications
At this point, we have the source control and compiler plugins configured, but the last big thing that we need to do is setup some way to be notified if a build fails. In this example, we’ll be setting up email notifications, however, there are plugins for many popular communication tools (Slack, HipChat, etc..).
To configure the email notifications, go to the System Configuration screen and find the Jenkins Location section. Here, specify the System Admin e-mail address for Jenkins (this does not have to be a valid email address, but it does need to be entered).
After entering an email for Jenkins, find the E-mail Notification section. This is where we will specify what mail server and other options to send out the notifications.
Since we’re using Gmail for our communications, we need to specify that in the SMTP server field and we need to click the Advanced… button to have some more configuration.
After clicking the button, entering the following values for each field (substituting your own Gmail address and password)
To ensure that the email notification is configured correctly, click the Test Configuration by sending test e-mail button and enter a valid email address.
When you click the button, you should get a success message. If, however, you get the following message, it’s probably due to Google locking down access to less secure 3rd party applications.
If that’s the case, you will need to tweak your Gmail settings (http://accounts.google.com/security) so that less secure applications can access your account (see below).
In this post, we installed Jenkins, a continuous integration server. Next, we installed the Mercurial and MSBuild plugins. After installing the plugins, we configured them to work with the installed tools. Finally, we configured Jenkins to send emails notifications through Gmail that allows Jenkins to alert us when a build fails.
In the final post for the series, we will be creating a simple job that will checkout a .NET solution, compile it, and deploying it to a different server.