openstack team mailing list archive

[Sheng Bo Hou <sbhou@xxxxxxxxxx>]

Hi there from OpenStack Community,

After the research done by my colleage Edward Zhang and myself, we have 
found the following issues for openstack. We have already raised bug 
https://bugs.launchpad.net/nova/+bug/974810. 

1. The ROOT cause that i18n did not work in Nova
In Nova, within nova.image, there is a python file glance.py. This file 
has a line of code GlanceClient = 
utils.import_class('glance.client.Client'),
which calls the class glance.client.Client from Glance project. Each time 
this line of code is called, the gettext domain will change from nova to 
glance. But it doesn't recover nova domain after glance client returns the 
control. So the i18n won't be correctly working in nova.

Detailed explanation: 
Within Nova.__init__.py, there is gettext.install('nova', unicode=1). If 
we want to make i18n (e.g. Chinese) work, 
we need to modify it into gettext.install('nova', [path of locale 
directory], unicode=1). The first parameter "nova" is the domain for i18n 
within nova project. 
However, when the code as the right image shows is called, 
gettext.install('glance', unicode=1) within glance.__init__.py will be 
called. So the domain switches 
from 'nova' to 'glance', though we are still running the nova project. 
Nova project needs 'nova' as the domain. When the domain changes, 
certainly i18n will fail.


2. Differences between the development mode and the operation mode
We are using devstack to run our environment. As we talked about changing 
gettext.install('nova', unicode=1) into 
gettext.install('nova', [path of locale directory], unicode=1) before, 
this may lead to another issue. gettext.install has a default directory, 
which is where openstack
can install its locale files, like all the .mo files. However, devstack 
does not install locale files in the default directory, which is why we 
need to make the change.
We suggest that openstack have two modes: development and operation. 
Different modes have different settings for the paths.
 

3. Improvement of the context management
There is blueprint about decoupling client code of glance from the glance 
project and there is a python-glaceclient under development. It can 
resolve i18n issue potentially, since
nova won't call glance directly and glance domain won't be loaded in nova. 
In our opinion, we would call it AVOID it rather than RESOLVE it. If we go 
one step further, 
this indicates that there is an issue for the context management. 
OpenStack has different projects and different logging environments, etc, 
which we call context.
It is natual for us to switch context b/w different program, e.g. from 
nova to glance. In nova, there is no clear management and indication that 
the context 
has been changed or clear exist for the context to switch back. The i18n 
issue is just a tip of the iceberg for the context management. It is a 
potential improvement for openstack.

We hope the above information can help OpenStack become better and we 
would like to hear more comments from our community.
Thank you very much.

Best wishes.
Vincent Hou (侯胜博)

Software Engineer, Standards Growth Team, Emerging Technology Institute, 
IBM China Software Development Lab

Tel: 86-10-82450778 Fax: 86-10-82453660
Notes ID: Sheng Bo Hou/China/IBM@IBMCN    E-mail: sbhou@xxxxxxxxxx 
Address:3F Ring, Building 28 Zhongguancun Software Park, 8 Dongbeiwang 
West Road, Haidian District, Beijing, P.R.C.100193