Organize translation usage

Registered by Ekaterina Chernova

Translation is used randomly all over the code.
We need to organize it's usage and set up translation usage as it defined in Openstack guides.

1) Remove gettextutils usage and replace it with oslo.i18n
2) Remove exception messages translation;
3) Remove translation from debug messages;
4) Add log translation to info, warn and error log level (introduce LW, LE, LI)
log.exception which creates log.error message - so it's needed to be logged

Blueprint information

Status:
Complete
Approver:
Ekaterina Chernova
Priority:
Medium
Drafter:
Ekaterina Chernova
Direction:
Approved
Assignee:
Kirill Zaitsev
Definition:
Approved
Series goal:
Accepted for kilo
Implementation:
Implemented
Milestone target:
milestone icon 2015.1.0
Started by
Kirill Zaitsev
Completed by
Kirill Zaitsev

Related branches

Sprints

Whiteboard

> Remove exception messages translation

This requirement looks excessive. It means that any string that goes into an exception should not be marked for translation. But at the same time docs for oslo.i18n do that all the time. http://docs.openstack.org/developer/oslo.i18n/guidelines.html#examples

Moreover if parts of our application communicate via exceptions — we can possibly face a situation, where we raise a recoverable exception with untranslated string and later log it like this: logging.exception("exception occured during foo %s", e)
Which would cause untranslated string to appear in logs.

Gerrit topic: https://review.openstack.org/#q,topic:bp/organize-translation,n,z

Addressed by: https://review.openstack.org/157329
    Use oslo.i18n for translation

(?)

Work Items

This blueprint contains Public information 
Everyone can see this information.