Le 23/10/2015 12:22, Jan Henning Thorsen a écrit :
If it's not critical that changes in the file is visible instantly, you
could do something like this:
It's not critical if the changes appears after a few seconds, so the
idea is good, thank you -- and thanks for the code, which is helpful.
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.
I didn't like the idea of checking a mtime each time I did a request to
the data -- which would be almost each time a user displays a page.
Feels like loosing the efficiency of having everything in memory.
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)
Oh, I didn't know of that one. And really like it, for it respects the
data/file paradigm for understandability.
It may indeed be the best solution, among other things for portability.
I will give it a try, and report back to the list next week.
Really good advice, thanks!
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".
Yes, smart! Still GTK (Good To Know (tm)).
Thanks again,
--
Boris
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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