Hi Stephan,
IMO the platform needs better jobs isolation. All this shading shouldn't
be required at all.
Michal
On 20.07.2016 16:18, Stephan Ewen wrote:
Hi Michael!
The only safe way in Java to isolate the user code from the platform
would be to completely run them in different JVMs.
Other than that, Max's method to ensure the correct instantiation
should work in most cases.
We also continuously try to have fewer dependencies in Flink, to that
there is less to clash.
Stephan
On Wed, Jul 20, 2016 at 3:53 PM, Maximilian Michels <m...@apache.org
<mailto:m...@apache.org>> wrote:
Sure. No Problem.
The issue is a bit more involved. You're right, the user classes have
precedence over the Flink classpath. So your classes were probably
loaded fine. However, the user code also calls Flink code which can
use a library version different from the job jar library. And boom, it
crashes because the job jar library has been loaded previously :)
The only way we could circumvent this problem would be to explicitly
set a different classloader and load Flink internal classes via
reflection. I think the performance penalty for this would be way too
high.
Best,
Max
On Wed, Jul 20, 2016 at 2:23 PM, Michal Budzyn
<michal.budzyn.ext...@zalando.de
<mailto:michal.budzyn.ext...@zalando.de>> wrote:
> Thanks for the prompt replay.
>
> You are right. The conflict was between
"com.fasterxml.jackson.core" libs.
>
> I am just wondering. If the the jobs were separted from the
platform,
>
> the jobs libs should have precedence and no versioning problem
should have
> happened.
>
> Regards,
>
> Michal
>
>
>
> On 20.07.2016 14:00, Maximilian Michels wrote:
>>
>> Hi Michal,
>>
>> I couldn't find Joda in flink-dist. Possibly there is some
other clash?
>>
>> There are two potential issues here:
>>
>> 1) Flink shades some libraries (Guava) but not all. If you use a
>> version of a library in your Flink job which doesn't match the
one in
>> flink-dist, you're bound for trouble.
>>
>> 2) Flink separates jobs from each other to avoid potential class
>> version mismatches. Each job has its own classloader. In this
sense,
>> "job versioning" is supported.
>>
>> Cheers,
>> Max
>>
>> On Wed, Jul 20, 2016 at 1:02 PM, Michal Budzyn
>> <michal.budzyn.ext...@zalando.de
<mailto:michal.budzyn.ext...@zalando.de>> wrote:
>>>
>>> Hi all,
>>> We had a class versioning problem within Flink Job.
>>> The job uses Joda 2.6, but the flink-dist 1.0.3 packages 2.5.
>>> The problem was solved by relocating job classes with shade
plug-in.
>>>
>>> Does flink separate jobs from each other to avoid class
conflicts between
>>> them and the platform ?
>>> Is job versioning supported or is shading always required ?
>>>
>>> Regards,
>>> Michal
>>>
>
