Skip to main content

Debugging random webdriver issues on jenkins

So one of my friend was facing one issue where he wrote a bunch of webdriver tests and they all work fine but when he runs on jenkins slave it randomly fails.  He runs his jenkins job hourly and problem is that it fails may be 4 times in 24 hours.  So how do you debug the issue, well he was adding loggers in the test to figure this out and then plodding over logs to figure out what went wrong. This is quite a bit of guess work and I thought sometimes a picture is better than 1000 words. So it would be nice if I could take a screenshot when the test errors out and then save it as an artifact. Guess what the webdriver already has an api for that. So all i needed to do was to add a TestRule like this and add the screenshots directory in the publish artifacts in jenkins.  I will know it in a week or so if this would save him a lot of time or not.

    @Rule
    public TestRule testWatcher = new TestWatcher() {
        @Override
        public void failed(Throwable t, Description test) {
            takeScreenshot(test.getDisplayName() + UUID.randomUUID().toString());
        }

        private void takeScreenshot(String screenshotName) {
            WebDriver webDriver = driver.getWebDriver();
            if (webDriver instanceof TakesScreenshot) {
                File targetDir = new File("seleniumScreenshots");
                File targetFile = new File(targetDir, screenshotName + ".png");
                logger.info("Taking Screenshot path = " + targetFile);
                File tempFile = ((TakesScreenshot) webDriver).getScreenshotAs(OutputType.FILE);
                try {
                    FileUtils.copyFile(tempFile, targetFile);
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    };

Comments

Popular posts from this blog

RabbitMQ java clients for beginners

Here is a sample of a consumer and producer example for RabbitMQ. The steps are
Download ErlangDownload Rabbit MQ ServerDownload Rabbit MQ Java client jarsCompile and run the below two class and you are done.
This sample create a Durable Exchange, Queue and a Message. You will have to start the consumer first before you start the for the first time.

For more information on AMQP, Exchanges, Queues, read this excellent tutorial
http://blogs.digitar.com/jjww/2009/01/rabbits-and-warrens/

+++++++++++++++++RabbitMQProducer.java+++++++++++++++++++++++++++
import com.rabbitmq.client.Connection; import com.rabbitmq.client.Channel; import com.rabbitmq.client.*; public class RabbitMQProducer { public static void main(String []args) throws Exception { ConnectionFactory factory = new ConnectionFactory(); factory.setUsername("guest"); factory.setPassword("guest"); factory.setVirtualHost("/"); factory.setHost("127.0.0.1"); factory.setPort(5672); Conne…

Logging to Graphite monitoring tool from java

We use Graphite as a tool for monitoring some stats and watch trends. A requirement is to monitor impact of new releases as build is deployed to app nodes to see if things like
1) Has the memcache usage increased.
2) Has the no of Java exceptions went up.
3) Is the app using more tomcat threads.
Here is a screenshot

We changed the installer to log a deploy event when a new build is deployed. I wrote a simple spring bean to log graphite events using java. Logging to graphite is easy, all you need to do is open a socket and send lines of events.
import org.slf4j.Logger;import org.slf4j.LoggerFactory; import java.io.OutputStreamWriter; import java.io.Writer; import java.net.Socket; import java.util.HashMap; import java.util.Map; public class GraphiteLogger { private static final Logger logger = LoggerFactory.getLogger(GraphiteLogger.class); private String graphiteHost; private int graphitePort; public String getGraphiteHost() { return graphiteHost; } public void setGraphite…

What a rocky start to labor day weekend

Woke up by earthquake at 7:00 AM in morning and then couldn't get to sleep. I took a bath, made my tea and started checking emails and saw that after last night deployment three storage node out of 100s of nodes were running into Full GC. What was special about the 3 nodes was that each one was in a different Data centre but it was named same app02.  This got me curious I asked the node to be taken out of rotation and take a heap dump.  Yesterday night a new release has happened and I had upgraded spymemcached library version as new relic now natively supports instrumentation on it so it was a suspect. And the hunch was a bullseye, the heap dump clearly showed it taking 1.3G and full GCs were taking 6 sec but not claiming anything.



I have a quartz job in each jvm that takes a thread dump every 5 minutes and saves last 300 of them, checking few of them quickly showed a common thread among all 3 data centres. It seems there was a long running job that was trying to replicate pending…