Wednesday, March 13, 2013

Awesome new graphs in RHQ - based on d3.js

Mike Thompson has yesterday presented the latest and greatest version of the new graphs for RHQ in a video on YouTube. Shortly after he has committed the results of his huge work into RHQ master branch.

While this work is not yet finished, it is the result of the work started by Denis Krusko in last years Google Summer of Code. At the moment both the old and new graphs are can be looked at in the UI, so that you can compare them and potentially report non-matches.

Here are some screenshots to foster your appetite:

Popup chart for a single metric
Popup chart for a single metric

Individual metric
Individual metric on the monitoring tab

As the subject already says are those graphs made with the help of the awesome D3.js framework - I let Mike chime in to describe in more details what he and Denis had to do to get this to work inside GWT+SmartGWT.

I've uploaded a snapshot from master as of this morning (my time) of this from our CI server onto SourceForge for you to try. THIS IS NOT FOR PRODUCTION.

There is a known issue where the red bar shows " exception.." this is harmless and we will fix that anyway. Also the graph portlets in the dashboard don't honor the column width yet.

Please do not forget to report bugs (if there are any :-)

Thursday, March 07, 2013

Sorry Miss Jackson -- or how I loved to do custom Json serialization in AS7 with RestEasy

Who doesn't remember the awesome "Sorry Miss Jackson" video ?

Actually that doesn't have to do anything with what I am talking here -- except that RestEasy inside JBossAS7 is internally using the Jackson json processing library. But let me start from the beginning.

Inside the RHQ REST api we have exposed links (in json representation) like this:


which is the natural format when a Pojo

class Link {
String rel;
String href;

is serialized (with the Jackson provider in RestEasy).

Now while this is pretty cool, there is the disadvantage that if you need the link for a rel of 'edit', you had to load the list of links, iterate over them and check for each link if its rel is 'edit' and then take the value of the href.

And there is this Bugzilla entry.

I started investigating this and thought, I will use a MessageBodyWriter and all is well. Unfortunately MessageBodyWriters do not work recursively and thus cannot format Link objects as part of another object in a special way.

Luckily I have done custom serialization with Jackson in the as7-plugin before, so I tried this, but the Serializer was not even instantiated. More trying and fiddling and a question on StackOverflow led me to a solution by copying the jackson libraries (core, mapper and jaxrs) into the lib directory of the RHQ ear and then all of a sudden the new serialization worked. The output is now

{ "self":
{ "href" : "http://..." }

So far so nice.

Now the final riddle was how to use the jackson libraries that are already in user by the resteasy-jackson-provider. And this was solved by adding respective entries to jboss-deployment-structure.xml, which ends up in the META-INF directory of the rhq.ear directory.

The content in this jboss-deployment-structure.xml then looks like this (abbreviated):

<sub-deployment name="rhq-enterprise-server-ejb3.jar">
<module name="org.codehaus.jackson.jackson-core-asl" export="true"/>
<module name="org.codehaus.jackson.jackson-jaxrs" export="true"/>
<module name="org.codehaus.jackson.jackson-mapper-asl" export="true"/>

AS7 is still complaining a bit at startup:

16:48:58,375 WARN [] (MSC service thread 1-3) JBAS018567: Deployment "deployment.rhq.ear.rhq-enterprise-server-ejb3.jar" is using a private module ("org.codehaus.jackson.jackson-core-asl:main") which may be changed or removed in future versions without notice.

but for the moment the result is good enough - and as we do not regularly change the underlying container for RHQ, this is tolerable.

And of course I would be interested in an "official" solution to that -- other than just doubling those jars into my application (and actually I think this may even complicate the situation, as (re-)using the jackson jars that RestEasy inside as7 uses, guarantees that the version is compatible).