Yes, this is a concern if attributes are not read-only. The wiki article on
xtypes has a section about this:
https://github.com/weewx/weewx/wiki/WeeWX-V4-user-defined-types#subtlety

On Tue, Feb 16, 2021 at 1:26 PM Karen K <[email protected]> wrote:

> Another question: Is it possible that cheetah generator and image
> generator call the XType extension in parallel from different threads?
>
> If so, I guess, locking would be needed for code that alters class
> attributes.
>
> Karen K schrieb am Sonntag, 14. Februar 2021 um 21:55:10 UTC+1:
>
>> "Mostly the problem is situated between the chair and the screen." I
>> should read the documentation more carefully.
>>
>> $day and $yesterday need some aggregation. So it is *not possible* to
>> write $day.GTS or $yesterday.GTS because the aggregation type is
>> missing. Instead it is necessary to write $day.GTS.last or
>> $yesterday.GTS.last or something. And then there is a value, even
>> without having the values in the database. Providing the get_aggregate()
>> function is sufficient.
>>
>> And in this extension all the values are based on outTemp, and outTemp is
>> included in the database.
>> Tom Keffer schrieb am Sonntag, 14. Februar 2021 um 19:33:00 UTC+1:
>>
>>> To show a value for yesterday, the value would have to be in the
>>> database.
>>>
>>> On Sun, Feb 14, 2021 at 10:29 AM Karen K <[email protected]> wrote:
>>>
>>>> Oh, so I mixed it up some way. I registered the XType as a service.
>>>>
>>>> Now there are two different classes, and that looks a lot better. The
>>>> extension calculates the values and draws a graph. Thank you for your
>>>> advice. It saved a lot of time.
>>>>
>>>> $current.GTS displays a value now. $day.GTS and $yesterday.GTS do not.
>>>>
>>>> Tom Keffer schrieb am Samstag, 13. Februar 2021 um 23:37:58 UTC+1:
>>>>
>>>>> Good start!
>>>>>
>>>>> I can see a few issues here.
>>>>>
>>>>> 1. All xtype extensions must be registered, otherwise the system has
>>>>> no way of knowing of their existence. See the section *Registering
>>>>> your subclass
>>>>> <https://github.com/weewx/weewx/wiki/WeeWX-V4-user-defined-types#registering-your-subclass>*
>>>>>  for
>>>>> how to register your xtype.
>>>>>
>>>>> 2. From what I can tell, your extension only returns a value for
>>>>> 'GTSdate', never for 'GTS'.
>>>>>
>>>>> 3. I don't quite follow the logic of the loop in get_scalar(), but it
>>>>> looks like it is trying to keep a running total of something. Just a
>>>>> warning: this could be very inefficient because an xtype can potentially
>>>>> get called many times in a template. Would it be possible to refactor into
>>>>> a database query?
>>>>>
>>>>>
>>>>>
>>>>> On Sat, Feb 13, 2021 at 1:05 PM Karen K <[email protected]> wrote:
>>>>>
>>>>>> And the cheetah generator's result is
>>>>>>
>>>>>> Karen K schrieb am Samstag, 13. Februar 2021 um 22:04:36 UTC+1:
>>>>>>
>>>>>>> test skin index.html.tmpl
>>>>>>>
>>>>>>> --
>>>>>> You received this message because you are subscribed to the Google
>>>>>> Groups "weewx-development" group.
>>>>>> To unsubscribe from this group and stop receiving emails from it,
>>>>>> send an email to [email protected].
>>>>>> To view this discussion on the web visit
>>>>>> https://groups.google.com/d/msgid/weewx-development/1f9090b4-308a-4029-9d84-fcfba0229171n%40googlegroups.com
>>>>>> <https://groups.google.com/d/msgid/weewx-development/1f9090b4-308a-4029-9d84-fcfba0229171n%40googlegroups.com?utm_medium=email&utm_source=footer>
>>>>>> .
>>>>>>
>>>>> --
>>>> You received this message because you are subscribed to the Google
>>>> Groups "weewx-development" group.
>>>> To unsubscribe from this group and stop receiving emails from it, send
>>>> an email to [email protected].
>>>>
>>> To view this discussion on the web visit
>>>> https://groups.google.com/d/msgid/weewx-development/09de8f6e-1063-492f-8b4b-add16d6d78den%40googlegroups.com
>>>> <https://groups.google.com/d/msgid/weewx-development/09de8f6e-1063-492f-8b4b-add16d6d78den%40googlegroups.com?utm_medium=email&utm_source=footer>
>>>> .
>>>>
>>> --
> You received this message because you are subscribed to the Google Groups
> "weewx-development" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to [email protected].
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/weewx-development/02644e98-189c-4857-87cb-2780e7653f56n%40googlegroups.com
> <https://groups.google.com/d/msgid/weewx-development/02644e98-189c-4857-87cb-2780e7653f56n%40googlegroups.com?utm_medium=email&utm_source=footer>
> .
>

-- 
You received this message because you are subscribed to the Google Groups 
"weewx-development" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to [email protected].
To view this discussion on the web visit 
https://groups.google.com/d/msgid/weewx-development/CAPq0zEBEiWsKodjB8fLu%2B9JHbv7qBSPoiukoDBn3%3DcHnuH1DLQ%40mail.gmail.com.

Reply via email to