If it's not critical that changes in the file is visible instantly, you
could do something like this:
Mojo::IOLoop->recurring(
30 => sub {
app->config(dashboard => decode_json(slurp
app->home->rel_file("dashboard.json")));
}
);
This will make the application read the file every 30 second and update the
"dashboard" config parameter. The code could also check if the timestamp of
the json file has changed and simply not read the content if mtime is the
same.
Another idea is to use AnyEvent::Filesys::Notify instead of the recurring
timer. (There might be similar solutions, but that was the one that came to
mind first)
About hot reloading: If you are running both the workers and manager as the
same user, then the worker can do initiate hot reload using "kill USR2 =>
getppid".
On Friday, October 23, 2015 at 10:10:46 AM UTC+2, Boris Baldassari wrote:
>
> Hi Jan,
>
> The app is a kind of dashboard for sw project assessment, and it maintains
> a set of data on software projects (metrics, meta-information, etc.). There
> is an analysis (i.e. an update on this data) started every day, plus
> occasional changes on user's initiative. So the information is not changing
> *heavily*.
>
> My point is I *want* to maintain the data on disk as json files, because I
> believe that a data-based process (i.e. having a process transforming data
> between known states) is easier to read and understand for users and
> maintainers.
> After giving some thoughts to memcache/redis/etc. I realise I would have
> to synchronise the data on disk every time it changes, which is quite
> cumbersome and not very reliable.
>
> Maybe hot reloading hypnotoad would be the way to go. How could I do that
> from the code itself, apart from executing shell commands?
>
> Another option would be to load the data at startup, and write it down to
> the disk on shutdown (through a END sub). Not sure about the reliability of
> such a solution though.
>
> Any idea would be welcome. Thanks!
>
> --
> Boris
>
>
>
> Le jeudi 22 octobre 2015 12:52:07 UTC+2, Jan Henning Thorsen a écrit :
>>
>> Could you give some more details/examples on what kind of information
>> that is changed during run? Also, how often does this information change?
>>
>> Reason for asking, is that you might come up with a far too complicated
>> solution for this.
>>
>> In some cases, it would be enough to just change the config file and then
>> hot reload hypnotoad, but this won't work if you're changing the config too
>> often. On the other hand, reading data from memcache/redis/something is
>> probably a better idea than trying to synchronise information internally
>> between your workers.
>>
>>
>> On Wednesday, October 21, 2015 at 12:16:51 PM UTC+2, Boris Baldassari
>> wrote:
>>>
>>> Hi Ben,
>>>
>>> Thank you for the quick and to-the-point answer. I guess it won't work
>>> either with prefork instead of hypnotoad.
>>>
>>> I'll have a look at memcache and redis solutions.
>>>
>>> Thanks again -- I've spent some time on this, so it's good to have a
>>> confirmation/statement to settle the point.
>>>
>>> Have a great day!
>>>
>>> --
>>> boris
>>>
>>>
>>>
>>> Le mercredi 21 octobre 2015 11:14:42 UTC+2, Ben van Staveren a écrit :
>>>>
>>>> That won't work - under Hypnotoad every worker would end up with it's
>>>> own copy, and while you would be able to update values inside a single
>>>> worker, it wouldn't work across the entire worker pool. Consider using
>>>> memcache or another key/value store that's convenient (redis, perhaps) to
>>>> store information like that, and fetch it when required.
>>>>
>>>>
>>>> On 10/21/2015 11:10 AM, Boris Baldassari wrote:
>>>>
>>>> Hiho dear Mojo folks,
>>>>
>>>> This is my first post here, so I'd like to start with a big thank you
>>>> all for the work put on mojolicious. It just rocks. :-)
>>>>
>>>> I am building a full (not light) app which needs access to a set of
>>>> variables (say config) stored in a dedicated module
>>>> (MyApp::Model::Config).
>>>> These values do change during the run, and I want all the workers to
>>>> access
>>>> the new values. This works very well in morbo, but as soon as I start
>>>> using
>>>> hypnotoad the values are not updated for all workers. As a consequence,
>>>> depending on the worker serving your request you get either old or new
>>>> values randomly.
>>>>
>>>> I started with a singleton helper put directly in the startup method:
>>>>
>>>> $app->helper( repo => sub { state $config =
>>>> MyApp::Model::Config->new($app) } );
>>>> This doesn't resolve the issue.
>>>>
>>>>
>>>> Then I read about similar problems with db connection handles, and I
>>>> decided to move them out of the startup method and I added some has
>>>> attributes, still in the MyApp.pl class:
>>>>
>>>> has my_config => sub { state $config = MyApp::Model::Config->new($app); };
>>>>
>>>> But it still doesn't work.
>>>>
>>>> So, how should I do that? Any advice on the design or code itself is
>>>> welcome...
>>>>
>>>> Thanks in advance,
>>>>
>>>> --
>>>> Boris
>>>> --
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>>>>
>>>>
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