Sending a notification to the main nginx thread

[Dk Jack]

I haven't played with them myself, but have considered sub-requests? Since
your are using a library with its own event-loop, perhaps it's best to run
it in its own process and use nginx sub-requests to bridge the two
processes? Seems doable.
https://nginx.org/en/docs/dev/development_guide.html#http_subrequests

Dk.

On Wed, Oct 6, 2021 at 12:53 PM Eran Kornblau <eran.kornblau at kaltura.com>
wrote:

> >
> > -----Original Message-----
> > From: nginx-devel <nginx-devel-bounces at nginx.org> On Behalf Of Maxim
> Dounin
> > Sent: Wednesday, 6 October 2021 16:12
> > To: nginx-devel at nginx.org
> > Subject: Re: Sending a notification to the main nginx thread
> >
> > Hello!
> >
> > First of all, you may want to take a look at this warning in the
> development guide:
> >
> >
> https://eur02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fnginx.org%2Fen%2Fdocs%2Fdev%2Fdevelopment_guide.html%23threads_pitfalls&data=04%7C01%7C%7Cd0de648d5c294e07aac008d988cae55b%7C0c503748de3f4e2597e26819d53a42b6%7C1%7C1%7C637691227285308685%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=%2BiDgCqNY6Wtl0elz%2FYAG7UvdOmoW%2BsZg9v0i5Oicc%2FY%3D&reserved=0
> >
> > Quoting it here:
> >
> > It is recommended to avoid using threads in nginx because it will
> definitely break things: most nginx functions are not thread-safe. It is
> expected that a thread will be executing only system calls and thread-safe
> library functions.
> > If you need to run some code that is not related to client request
> processing, the proper way is to schedule a timer in the init_process
> module handler and perform required actions in timer handler. Internally
> nginx makes use of threads to boost IO-related operations, but this is a
> special case with a lot of limitations.
> >
> Thanks Maxim, I completely get that, that is the reason I was looking for
> way to send a notification to the main thread, and didn't just try to call
> nginx functions from some other thread.
> In my case, I need to integrate with some 3rd party library that has its
> own event loop, it would require significant changes to the library to make
> it run inside nginx's event loop...
> So, my plan is to run it on a side thread, and send notifications between
> the threads, which would trigger some handler on the main thread whenever
> new data arrives.
> I can use ngx_notify for this, but if someone will use the module and also
> nginx's thread pool or some 3rd party module that uses ngx_notify, it will
> break.
> I think I can live with that, but would be nice to have a solution that is
> complete.
>
> Eran
>
> >
> > --
> > Maxim Dounin
> >
> https://eur02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fmdounin.ru%2F&data=04%7C01%7C%7Cd0de648d5c294e07aac008d988cae55b%7C0c503748de3f4e2597e26819d53a42b6%7C1%7C1%7C637691227285318679%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=j6ifgLEZxh6B60ZP2wGOoJMnb1JnaVig3Ja26LNoMk0%3D&reserved=0
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