Category Archives: Jenkins

Create a md5 hash of two text files which can be to used as property in Maven command on a Windows Jenkins slave

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I have to start a Maven build with a md5 hash as parameter:

mvn clean verify -Dchecksum=ea25acae60d51e86993efcc6757b31cd

This hash has to be generated from the contents of two configuration files (A.xml, B.xml)

The build is executed on a Jenkins slave running on Windows. So I have implement a PowerShell script:

$config_a = [IO.File]::ReadAllText("A.xml")
$config_b = [IO.File]::ReadAllText("B.xml")

$enc = [system.Text.Encoding]::UTF8
$data = $enc.GetBytes($config_a+$config_b)

$md5 = New-Object -TypeName System.Security.Cryptography.MD5CryptoServiceProvider
$hash = [System.BitConverter]::ToString($md5.ComputeHash($data)).ToLower().Replace("-", "")

write-host "Calculated Hashsum: " $hash

"CHECKSUM=$hash" | Out-File -Encoding ASCII ".\checksum.properties"

In the Jenkins job the generated properties file is read with the EnvInject Plugin to create the environment variable CHECKSUM.

In the build step ‘Invoke Maven top level’ the Maven build can now be started like this:

clean verify -Dchecksum=$CHECKSUM

Note: without ‘-Encoding ASCII’ the properties file is written as ‘Unicode’. The ‘EnvInject Plugin’ then creates a wrong environment variable and the build fails with:

FATAL: Invalid environment variable name: "ÿþchecksum" java.lang.IllegalArgumentException: Invalid environment variable name: "ÿþCHECKSUM"

How to git fetch without a ssh warning

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For monitoring the time it takes to clone one of our repositories from github.com had to get rid of the warning:

Warning: Permanently added 'github.com,192.30.252.129' (RSA) to the list of known hosts

I found the solution in this StackOverflow question:
“Warning: Permanently added to the list of known hosts” message from Git

I just had to add these line to

Display execution time of shell commands in seconds

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I first tried using the time utility but failed on converting the result into seconds:

$ { time ls -l >/dev/null; } 2>&1 | grep real | sed -e 's/real//g' | sed -e 's/ //g'
	0m0.006s

Searching the web I found a StackOverflow (Display execution time of shell command with better accuracy) post pointing me to a solution using the bash variable SECONDS

From the Bash Reference Manual:

SECONDS This variable expands to the number of seconds since the shell was started. Assignment to this variable resets the count to the value assigned, and the expanded value becomes the value assigned plus the number of seconds since the assignment.

Example:

$ SECONDS=0; sleep 5; echo "I slept for $SECONDS seconds"

I slept for 5 seconds

Install Oracle JDK 8 on CentOS 6.5

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Download RPM

jdk-8u5-linux-x64.rpm from http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html

$ wget --no-check-certificate --no-cookies --header 'Cookie: oraclelicense=accept-securebackup-cookie' http://download.oracle.com/otn-pub/java/jdk/8u5-b13/jdk-8u5-linux-x64.rpm
$ sudo rpm -ivh jdk-8u5-linux-x64.rpm

Make JDK 8 the default with ‘alternatives’

$ sudo alternatives --install /usr/bin/java java /usr/java/jdk1.8.0_05/jre/bin/java 20000

$ sudo alternatives --install /usr/bin/jar jar /usr/java/jdk1.8.0_05/bin/jar 20000
$ sudo alternatives --install /usr/bin/javac javac /usr/java/jdk1.8.0_05/bin/javac 20000
$ sudo alternatives --install /usr/bin/javaws javaws /usr/java/jdk1.8.0_05/jre/bin/javaws 20000

$ sudo alternatives --config java

There are 2 programs which provide 'java'.

  Selection    Command
-----------------------------------------------
*+ 1           /usr/lib/jvm/jre-1.7.0-openjdk.x86_64/bin/java
   2           /usr/java/jdk1.8.0_05/jre/bin/java

Enter to keep the current selection[+], or type selection number: 2


$ java -version
java version "1.8.0_05"
Java(TM) SE Runtime Environment (build 1.8.0_05-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.5-b02, mixed mode)

Bulk change subversion repository URL with jenkins-cli and Groovy code

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Create the file changeSvnUrl.groovy with this content:

import hudson.scm.*

// Access to the Hudson Singleton
jenkinsInstance = jenkins.model.Jenkins.instance

// Retrieve all jobs
allJobs = jenkinsInstance.items

svnCredentialsId = "c8xxxee-965c-4cc0-b662-8a5xxx7d41b"

// iterate over jobs with Subversion as SCM
allJobs.each { job ->
    if (job.scm instanceof SubversionSCM) {
        if (job.scm.locations[0].remote.startsWith("http://oldhost/svn")) {
            oldUrl = job.scm.locations[0].remote
            newUrl = oldUrl.replace("http://oldhost/svn", "https://newhost/svn/project")

            println("changing Subversion URL in " + job.name + " from " + oldUrl + " to " + newUrl)

            job.scm = new hudson.scm.SubversionSCM(newUrl)
            job.scm.locations[0] = job.scm.locations[0].withCredentialsId(svnCredentialsId)
        }
    }
}

Execute:

java -jar jenkins-cli.jar -s http://jenkinshost/ groovy changeSvnUrl.groovy

Authenticate jenkins-cli with ssh-key

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After adding the public key to your Jenkins user profile you can execute jenkins-cli with your ssh key:

$ java -jar jenkins-cli.jar -s http://hudson.hh.arvm.de/ -i ~/.ssh/jenkins_rsa who-am-i
Authenticated as: clsa1
Authorities:
  jenkins_admin

If you are using cygwin you have to transform the path like this:

java -jar jenkins-cli.jar -s http://hudson.hh.arvm.de/ -i $(cygpath -aw "/cygdrive/c/cygwin64/home/CLSA1/.ssh/jenkins_rsa")

Solved weird problem with executing JMeter tests on Jenkins slaves

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After a collegue of mine updated the Java version to 1.7 on our JMeter Jenkins slave (running on CentOS) all JMeter Projects stopped running.
The error message was:

Uncaught Exception java.lang.UnsatisfiedLinkError: /usr/java/jdk1.7.0_45/jre/lib/amd64/xawt/libmawt.so: libXtst.so.6: cannot open shared object file: No such file or directory.

When executed on console it worked.
I fired up a Vagrant VM and added this as Jenkins slave. JMeter worked on this slave also.
So I thought there must be something wrong with the Java installation.

When I searched for the missing library I found the solution:

[--@--]# locate libXtst.so.6
/usr/java/jdk1.6.0_29/jre/lib/amd64/xawt/libXtst.so.6
/usr/lib/libXtst.so.6
/usr/lib/libXtst.so.6.1.0

[--@--]# ll
/usr/java/jdk1.6.0_29/jre/lib/amd64/xawt/libXtst.so.6
lrwxrwxrwx 1 root root 10 Jul 16 2012
/usr/java/jdk1.6.0_29/jre/lib/amd64/xawt/libXtst.so.6 -> libmawt.so

The solution was to create a symbolic link:

[--@--]# cd /usr/java/jdk1.7.0_45/jre/lib/amd64/xawt/
[--@--]# ln -s libmawt.so libXtst.so.6

Adding a version number to the build history

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Add the following Groovy script:

def env = manager.build.getEnvironment();

if(manager.build.result.isBetterOrEqualTo(hudson.model.Result.UNSTABLE) && "true".equals(env['IS_M2RELEASEBUILD'])) {
    manager.addShortText("${manager.build.buildVariables.get('MVN_RELEASE_VERSION')}")
}

jenkins-version-label-postbuild

After performing a maven release the build history looks like this:

jenkins-version-label