Brian
Matt Kent wrote:
JMock is a unit testing tool for creating mock objects. I use it to mock things like OutputCollector and Reporter, so I can unit test mappers and reducers without running a cluster. In other words, I'm just testing the logic of the code within the map() and reduce() methods, and testing the map and reduce separately. I'm not feeding it real data from HDFS or running the code in a real cluster. Matt On Tue, 2008-06-17 at 18:50 -0700, Richard Zhang wrote:I creates three virtual machines, each of them works as a node. Does the JMock support debugging with multiple nodes cluster within Eclipse? Could we set up breakpoints, trace the running steps of the map reduce program? Richard On Mon, Jun 16, 2008 at 6:54 PM, Matt Kent <[EMAIL PROTECTED]> wrote:The approach I've taken is to use JMock and create a unit test for the mapreduce, then debug that within Eclipse on my workstation. For performance debugging, I use YourKit on the cluster. Matt On Mon, 2008-06-16 at 16:58 -0700, Mori Bellamy wrote:Hey Richard, I'm interested in the same thing myself :D. I was researching it earlier today, and the best I know to do is to use Eclipse's remote debugging functionality (although this won't completely work. each map/ reduce task spawns on its on JVM, making debugging really hard). but if you want, you can debug up until the mappers/reducers spawn. To do this, you need to pass certain debug-flags into the JVM. So you'd need to do export HADOOP_OPTS=myFLagsForRemoteDebug and then you'd go to eclips ->run->open debug dialog and set up remote debugging with the correct port. if you find out a way to debug the mappers/reducers on eclipse, let me know :D On Jun 16, 2008, at 3:10 PM, Richard Zhang wrote:Hello Hadoopers: Is there a way to debug the hadoop code from Eclipse IDE? I am using Eclipse to read the source and build the project now. How to start the hadoop jobs from Eclipse? Say if we can put the server names, could we trace the running process through eclipse, such as setting breakpoints, check the variable values? That should be very helpful for development. If anyone know how to do it, could you please give some info? Thanks. Richard
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