Set environment variable for build in hudson

Question

I am trying to put a maven2 project under continuous integration in hudson. The project uses selenium for some integration testing. Hudson is running on a headless linux. I am using xvfb to start a x server session for selenium.

In order to run the tests, I need to export an environment variable named DISPLAY. e.g.

export DISPLAY=:99

However, I don't want to set the variable on the box since it would affect all builds. I have tried to do a shell execute using the m2 extra steps plugin but it doesnt work since it is executed in a separate bash file, meaning that environment variables are not persisted.

Is there a way to register the environment variable from hudson.

Answer 1

Hudson's Node Properties would do a good job here. But if you're looking for a more automated way of assigning the screen number, you'll need to do a little more work, perhaps tying into the port-allocator plugin, or writing a new BuildWrapper plugin which starts up xvfb automatically, and sets the SCREEN environment variable on behalf of the build.

If you're willing to switch to a different X server for testing, you can try the Xvnc plugin for Hudson. It will start the vncserver automatically, and set the SCREEN environment variable as well. It also has the ability to take a screenshot when tests are finished, and show that in the job's Hudson page.

Answer 2

As per my response to the accepted answer, here are my findings.

Beware Un-initialised Variables

When using the Parametrization feature in Hudson, you can append environmental variables to the end of a string - provided that they contain something in the first place.

For example, if the environment variable $FOO is blank, and you were to use the following line in a String Parameter...

/usr/bin/ladeda/:$F00

then the environment variable will read /usr/bin/ladeda/:$F00.

However, if I did

export F00=/usr/bin/fiddledede

then the exported variable would be....

/usr/bin/ladeda/:/usr/bin/fiddledede

When I initially ran this as a test, I had not worked this out - and thus thought the parameter feature was not accepting external environment variables, when it actually was (they just had to contain something).

Answer 3

fyi, I'm releasing the setenv plugin for Hudson today (assuming java.net recovers enough for me to do so!) - it behaves similarly to the parameterized build functionality, but with a simpler UI (just a textarea for input - key/value pairs are separated by newlines) and without the need to provide values for the parameters at build-time.

Answer 4

I've found running selenium using xvfb-run to be more reliable than setting DISPLAY, so this might work for you. So:

xvfb-run java -jar selenium-server.jar

Answer 5

Have you tried to use the selenium maven plugin?

The plugin could be configured to start Xvfb, run the tests and then stop it.

using this pom.xml configuration:

<plugins>
    <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>selenium-maven-plugin</artifactId>
        <executions>
            <execution>
                <id>xvfb</id>
                <phase>pre-integration-test</phase>
                <goals>
                    <goal>xvfb</goal>
                </goals>
            </execution>

            <execution>
                <id>selenium</id>
                <phase>pre-integration-test</phase>
                <goals>
                    <goal>start-server</goal>
                </goals>
                <configuration>
                    <background>true</background>
                </configuration>
            </execution>
        </executions>
    </plugin>
</plugins>

the details are here: http://mojo.codehaus.org/selenium-maven-plugin/examples/headless-with-xvfb.html