Continuous Integration with Hudson/Jenkins

Our default Hudson runs on https://hudson.sapsailing.com. If you need access, please contact axel.uhl@sap.com or simon.marcel.pamies@sap.com. We have a build job running for the master branch which will automatically pick up any changes, run a build with tests and inform committers about flaws they introduced that broke the build.

It is good practice to set up a new Hudson job for major branches that require solid testing before being merged into the master branch. The entry page at http://hudson.sapsailing.com explains how to do this. It basically comes down to copying a template job and adjusting the branch name. As easy as that :-)

Collecting measurements using Hudson/Jenkins

If you have a test case that measures something, such as performance or level of fulfillment or any other numeric measure, you can have Hudson/Jenkins plot it. In your test case, use the class com.sap.sailing.domain.test.measurements.MeasurementXMLFile and add performance cases to which you add measurements, e.g., as follows:

        MeasurementXMLFile performanceReport = new MeasurementXMLFile(getClass());
        MeasurementCase performanceReportCase = performanceReport.addCase(getClass().getSimpleName());
        performanceReportCase.addMeasurement(new Measurement("My Measurement", theNumberIMeasured));
        performanceReport.write();

In case you'd like to set up your own Hudson/Jenkins

Initially we had trouble with Jenkins and the GIT plug-in. However, https://issues.jenkins-ci.org/browse/JENKINS-13381?focusedCommentId=196689&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-196689 explains that installing the Credentials plugin into Jenkins may help. Basically, what is needed over and above a plain Jenkins installation are the following plug-ins:

• Credentials
• Jenkins GIT
• Jenkins GIT Client
• Measurement Plots
• SSH Credentials
• Xvnc

Note, though that the Xvnc plug-in in version 1.16 seems to be causing some trouble (https://issues.jenkins-ci.org/browse/JENKINS-22105). Downgrading to 1.14 helps. The 1.14 .hpi file can be obtained, e.g., here: http://www.filewatcher.com/m/xvnc.hpi.21882-0.html.

Make sure that the environment used to run Hudson/Jenkins uses a UTF-8 locale. Under Linux, it's a good idea to set the environment variables

    export LC_ALL=en_US.UTF-8
    export LANG=us_US.UTF-8

which can, depending on how your Hudson/Jenkins is started, be included, e.g., in /etc/init/jenkins which then should have a section that looks like this:

script
    [ -r /etc/default/jenkins ] && . /etc/default/jenkins
    export JENKINS_HOME
    export LC_ALL=en_US.UTF-8
    export LANG=us_US.UTF-8
    exec start-stop-daemon --start -c $JENKINS_USER --exec $JAVA --name jenkins \
        -- $JAVA_ARGS -jar $JENKINS_WAR $JENKINS_ARGS --logfile=$JENKINS_LOG
end script

Other options for setting the locale include adding the LC_ALL and LANG variables to the /etc/environment file.

The basic idea of setting up a build job is to create a so-called "free-style software project" which then executes our configuration/buildAndUpdateProduct.sh script using the build parameter. Top-down, the following adjustments to a default free-style job that are required for a successful build are these:

• select "Git"
• enter ssh://trac@sapsailing.com/home/trac/git as the Repository URL
• create credentials using the Add button, e.g., pasting your private key and providing Jenkins with the password
• enter master for "Branches to build"
• under "Build Triggers" check "Poll SCM" and enter H/1 * * * * for the schedule which will check for updates in git every minute
• under "Build Environment" check "Run Xvnc during build"
• under "Build" select "Add build step" –> "Execute Shell" and paste as command something like this: ANDROID_HOME=/usr/local/android-sdk-linux configuration/buildAndUpdateProduct.sh build. Adjust the location of the Android SDK accordingly and install it if not already present.
• as Post-build Action, select "Publish JUnit test result report" and as Test report XMLs provide **/TEST-*.xml as the file pattern for the test reports.
• check the "Additional test reports features / Measurement Plots" box
• provide e-mail notification settings as you see fit

Hudson Master/Slave Set-Up

In order to elastically scale our build / CI infrastructure, we use AWS to provide Hudson build slaves on demand. The Hudson Master (https://hudson.sapsailing.com) has a script obtained from our git at ./configuration/launchhudsonslave which takes an Amazon Machine Image (AMI), launches it in our default region (eu-west-1) and connects to it. The AWS credentials are stored in the root account on hudson.sapsailing.com, and the hudson user is granted access to the script by means of an /etc/sudoers.d entry.

The image has been crafted specifically to contain the tools required for the build (as of this writing in particular Google Chrome, chromedriver and an old Firefox 26.0, plus a current Maven installation and the JDKs required for the build). In order to set up such an image based on Ubuntu, consider running the following commands as root (see also https://tecadmin.net/setup-selenium-chromedriver-on-ubuntu/), starting as the "ubuntu" used:

 scp -o StrictHostKeyChecking=false trac@sapsailing.com:/home/wiki/gitwiki/configuration/imageupgrade_functions.sh /tmp
 scp -o StrictHostKeyChecking=false trac@sapsailing.com:/home/wiki/gitwiki/configuration/hudson_slave_setup/* /tmp
 sudo -i
 apt-get update
 apt-get install -y unzip xvfb libxi6 libgconf-2-4
 curl -sS -o - https://dl-ssl.google.com/linux/linux_signing_key.pub | apt-key add
 echo "deb [arch=amd64]  http://dl.google.com/linux/chrome/deb/ stable main" >> /etc/apt/sources.list.d/google-chrome.list
 apt-get -y update
 apt-get -y upgrade
 apt-get -y autoremove
 apt-get -y install google-chrome-stable
 cd /tmp
 wget https://chromedriver.storage.googleapis.com/2.41/chromedriver_linux64.zip
 cd /usr/bin
 unzip /tmp/chromedriver_linux64.zip
 mv /tmp/imageupgrade /usr/local/bin
 mv /tmp/imageupgrade_functions.sh /usr/local/bin
 mv /tmp/mounthudsonworkspace /usr/local/bin
 mv /tmp/*.service /etc/systemd/system/
 source /usr/local/bin/imageupgrade_functions.sh
 download_and_install_latest_sap_jvm_8
 systemctl daemon-reload
 adduser --system --shell /bin/bash --quiet --group --disabled-password hudson
 sudo -u hudson mkdir /home/hudson/.ssh
 echo "ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA6TjveiR+KkEbQQcAEcme6PCUHZLLU5ENRCXnXKaFolWrBj77xEMf3RrlLJ1TINepuwydHDtN5of0D1kjykAIlgZPeMYf9zq3mx0dQk/B2IEFSW8Mbj74mYDpQoUULwosSmWz3yAhfLRgE83C7Wvdb0ToBGVHeHba2IFsupnxU6gcInz8SfX3lP78mh4KzVkNmQdXkfEC2Qe/HUeDLdI8gqVtAOd0NKY8yv/LUf4JX8wlZb6rU9Y4nWDGbgcv/k8h67xYRI4YbtEDVkPBqCZux66JuwKF4uZ2q+rPZTYRYJWT8/0x1jz5W5DQtuDVITT1jb1YsriegOZgp9LfS11B7w== hudson@ip-172-31-28-17" >/home/hudson/.ssh/authorized_keys
 sudo -u hudson wget -O /home/hudson/slave.jar "https://hudson.sapsailing.com/jnlpJars/slave.jar"

Furthermore, the ephemeral storage is partitioned with a gpt label into a swap partition with 8GB and the remainder as an ext4 partition mounted under /ephemeral/data with is then bound with a "bind" mount to /home/hudson/workspace. See the /etc/systemd/system/mounthudsonworkspace.service systemd service definition on the slave instances. The launchhudsonslave script launches the instance, checks for it to enter the running state, then tries to connect using SSH with user hudson. The respective keys are baked into the image and match up with the key stored in hudson@hudson.sapsailing.com:.ssh.

The launchhudsonslave script will then establish the SSH connection, launching the slave.jar connector. When the Hudson Master disconnects, the Java VM running slave.jar will terminate, and the next script command of launchhudsonslave will shutdown the host. This is possible for user hudson due to corresponding entries under /etc/sudoers.d. The hosts are launched such that shutting them down will terminate the Amazon EC2 instance.

Hudson patch for mail-1.6.2

With JDKs around 1.8.0_291 an original Hudson installation faces trouble when sending out e-mails through TLS-secured SMTP servers such as Amazon Simple Email Service (SES). The problem can be solved by replacing WEB-INF/lib/mail-1.4.4.jar in the /usr/lib/hudson/hudson.war file by a newer copy, such as mail-1.6.2.jar, sometimes also referred to as com.sun.mail-1.6.2.jar or javax.mail-1.6.2.jar. A correspondingly patched version can be found at https://static.sapsailing.com/hudson.war.patched-with-mail-1.6.2.