Error while creating report on OpenERP 7.0 with multiple workers

[sebalix]

Original report : https://bugs.launchpad.net/oerplib/+bug/1371790

Oerplib fails to generate reports when OpenERP 7.0 is running in multi-process mode using 'workers=N'.

Steps to reproduce:

1. make sure that workers = N (where N > 0) is in openerp-server.conf
2. Create a new database with demo data enabled
3. install 'warehouse' and 'sale' modules. These modules will create demo sale order
4. Use the following snippet to see the error:

import oerplib

oerp = oerplib.OERP(server='localhost', database='test', version='7.0')
oerp.login(user='admin', passwd='test')

print oerp.report('sale.order', 'sale.sale', [8])

The following error is produced:

Traceback (most recent call last):
  File "/home/etsinko/work/PyqtTest/pyqt/widgets/test.py", line 7, in <module>
    print oerp.report('sale.order', 'sale.sale', [8])
  File "/usr/local/lib/python2.7/dist-packages/oerplib/oerp.py", line 317, in report
    report_type, context)
  File "/usr/local/lib/python2.7/dist-packages/oerplib/oerp.py", line 347, in _get_report_data
    raise error.RPCError("Unknown error occurred during the "
oerplib.error.RPCError: Unknown error occurred during the download of the report.

1. If you set workers = 0 in openerp-server.conf the snippet prints out the name of the temporary file in which report is contained

[etsinko]

Sebastien, Do you still need a server log? I can post it if you need it.

[sebalix]

No it's fine, thank you. The fix is ready, just some tests remaining and I will push it (maybe tonight). Thanks!

[etsinko]

Thank you Sebastien, Maybe it is too late since the fix is ready but I realized that the issue was with OerpLib connecting again to OpenERP server to download the report, while OpenERP server used a new worker process to do that.

[sebalix]

Yes, this is exactly that. In fact, with OpenERP 5.0 and 6.0, the server was providing two methods to download reports: report and report_get. The first orders to the server to build a report, and the second must be called regularly to check if the report is ready to be downloaded. Multiprocess/workers appeared in OpenERP 6.1, and since the memory is not shared between two processes/requests... report_get has no clue about the report ordered by report I think. For this purpose OpenERP added the render_report RPC method, but OERPLib was not aware of it.

[etsinko]

Yes, I stumbled onto render_report method but I couldn't find any documentation about it.

[sebalix]

You can pull the develop branch if you want (it is stable enough). I will make a release later, there are some other stuff I need to check since the GitHub migration.