[ovirt-users] Change the timezone on the dashboard

[Scott Dickerson]

On Sat, Jan 28, 2017 at 12:06 AM, Oved Ourfali <oourfali at redhat.com> wrote:

> This is not possible at the moment.
> We had difficulties trying to get the one defined by the browser as well.
> As we go towards having all logs and audit to UTC in 4.2 the latest, for
> log aggregation purposes, we might not invest time in that as well.
>
> However, perhaps it can be easy to set this up in the ui plug-in
> definition. It will require manually editing the file, but it is a valid
> workaround.
>
> Scott / Vojtech, your thoughts?
>

Dashboard relies on ECMA-402 Intl.DateFormat spec [1] or the Polyfill [2].
The spec says that implementations need to, at the very least, support 2
time zones.  First is 'undefined' and equates to the "runtime's default
time zone".  Second is 'UTC'.  Since the first option is ambiguous and we
don't know what it is unless we parse a formatted string, using a default
of 'UTC' will provide the best cross-browser consistency.  Also, by forcing
to a UTC TZ, everyone looking at times on dashboard, no matter where they
are, will see the same times.

The Polyfill only supports the required 2 time zones.  See [3] for the
gritty details of their implementation.

Additionally, each browser may or may not support named TZs at all for date
formatting.  When I was trying to find a reasonable implementation to
support time zone switching, there was little consistency across browsers
(Firefox, Chrome, IE/Edge on Windows, Safari on Mac).  The Intl.DateFormat
javascript support just doesn't cover the TZ problem very well.

There is another solution - re-implement dashboard's date formatting to use
moment.js [4] and moment-timezone.js [5].  Doing so would let dashboard
have a user selectable TZ, but would incur the cost of shipping moment's JS
with locales (min-gz @ 67.9k) and timezones (min-gz @ 9.9k or 25.6k).
Wouldn't be difficult work.  It would just need to be given the green light.


TL;DR - Dashboard uses ECMA-402 and the spec doesn't require much TZ
support for Intl.DateFormat.  Because browsers don't support formatting
dates in different locales very well, UTC is used.  The safest way to
support explicitly selected TZs right now is to swap the date formatting
implementation out to one that uses momentjs.


[1] -
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DateTimeFormat
[2] - https://github.com/andyearnshaw/Intl.js
[3] -
https://github.com/andyearnshaw/Intl.js/blob/master/src/12.datetimeformat.js#L186
[4] - http://momentjs.com/
[5] - http://momentjs.com/timezone/


Regards,
Scott


> Thanks,
> Oved
>
> On Jan 27, 2017 19:01, "Logan Kuhn" <support at jac-properties.com> wrote:
>
>> Is there a way to change the timezone for the dashboard plugin?
>>
>> I've searched the list and the plugin files and can't seem to find where
>> it's set.
>>
>> Logan
>>
>> _______________________________________________
>> Users mailing list
>> Users at ovirt.org
>> http://lists.ovirt.org/mailman/listinfo/users
>>
>>


-- 
Scott Dickerson
Senior Software Engineer
RHEV-M Engineering - UX Team
Red Hat, Inc
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