[Engine-devel] Improve classpath building

[Juan Hernandez]

On 06/05/2012 03:03 PM, Oved Ourfalli wrote:
>
>
> ----- Original Message -----
>> From: "Juan Hernandez"<jhernand at redhat.com>
>> To: engine-devel at ovirt.org
>> Sent: Tuesday, June 5, 2012 3:53:08 PM
>> Subject: [Engine-devel] Improve classpath building
>>
>> Hello all,
>>
>> I would like to propose an improvement in the way we build
>> class-paths
>> in the tools associated to the engine. At the moment we have at least
>> two different ways to build classpaths:
>>
>> 1. Hard coded in the scripts, with maybe some variables:
>>
>> CP=$EAR_LIB/engine-encryptutils.jar:$EAR_LIB/engine-compat.jar:...
>>
>> This depends a lot on where we place the jar files, and we need to
>> place
>> them in different places in different environments if we want to
>> adhere
>> to common packaging practices.
>>
>> 2. Use the build-classpath script:
>>
>> CP=`build-classpath engine-encryptutils engine-compat ...`
>>
>> This depends less on the place we put them, but it doesn't work in
>> development environments where some jars are not installed to the
>> proper
>> system locations.
>>
>> None of these is good for all environments.
>>
>> I would like to replace this classpath building logic with an script
>> that performs the task in an smarter way and that works in all our
>> environments (production, development, Fedora, RHEL, etc).
>>
>
> In general it looks like a very good idea.
> Running the utilities in a development environment today is a real pain, so such a change will save a lot of time both when setting the development environment, and when testing changes.
>
> Didn't review all the whole source code, but from a quick glance I saw the preferredJars dictionary.
> IMO it is better to put this configuration in a configuration file, instead of a dictionary.
> Also, I would allow to change the path to this file, to allow developers to create a custom file (if they need one).

The idea of using a configuration file is nice, but I would make it 
completely optional, and would try to make every effort (almost) to make 
the script work without need for additional configuration.

>> My proposal is to create a "engine-java" script that we should use
>> always when invoking java programs. This script will receive the same
>> parameters that the "java" launcher receives, but the "-cp" or
>> "-classpath" options will contain not the absolute name of the jar
>> files, but just a simple jar name instead, something like
>> "commons-logging", "commons-codec" or "engineencryptutils". The
>> script
>> will extract the "-cp" or "-classpath" options given and use them to
>> do
>> a search of the jar files in the locations where they can be in
>> different environments:
>>
>> /usr/share/java
>> /usr/share/java/ovirt-engine
>> /usr/share/ovirt-engine/engine.ear
>> /usr/share/ovirt-engine/engine.ear/lib
>> <your jboss development installation>/engine.ear
>> <your jboss development installation>/engine.ear/lib
>>
>> In addition the script will check that all the give jar files exist
>> and
>> will abort the execution if any of them is missing.
>>
>> Find attached the initial version of the proposed script.
>>
>> Let me know what you think.
>>
>> Regards,
>> Juan Hernandez
>>
>> --
>> Dirección Comercial: C/Jose Bardasano Baos, 9, Edif. Gorbea 3, planta
>> 3ºD, 28016 Madrid, Spain
>> Inscrita en el Reg. Mercantil de Madrid – C.I.F. B82657941 - Red Hat
>> S.L.
>>
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-- 
Dirección Comercial: C/Jose Bardasano Baos, 9, Edif. Gorbea 3, planta 
3ºD, 28016 Madrid, Spain
Inscrita en el Reg. Mercantil de Madrid – C.I.F. B82657941 - Red Hat S.L.