# Long running http polling and event dispatch and how to move it to nameko.

**URL:** <https://discourse.nameko.io/t/long-running-http-polling-and-event-dispatch-and-how-to-move-it-to-nameko/152>\
**Category:** googlegroup\
**Created:** [September 10, 2016, 9:17am UTC](https://discourse.nameko.io/t/long-running-http-polling-and-event-dispatch-and-how-to-move-it-to-nameko/152 "2016-09-10T09:17:23Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Stephen\_Foster](https://avatars.discourse-cdn.com/v4/letter/s/76d3ee/32.png) [@Stephen\_Foster](https://discourse.nameko.io/u/Stephen_Foster)\
**Post date:** [September 10, 2016, 9:17am UTC](https://discourse.nameko.io/t/long-running-http-polling-and-event-dispatch-and-how-to-move-it-to-nameko/152/1 "2016-09-10T09:17:23Z")

</div>

Hi Guys (nameko + newbie = namekbie)

I've been messing with nameko for a very short while and I've thought it  
may be a great choice for what I want to do but I'm struggling with the  
best approach to perform something.

I currently have a class that opens a long running chunked http request and  
as chunks come down the line I want to emit an event ala pub/sub.  
Now I've managed to do this with a vanilla python class and creating a  
nameko event dispatcher in a stand alone mode(like in one of the examples).  
This does a great job of spitting out events as data comes down the long  
running http request.

Ideally.. (here is the rub) I would like that event streamer to respond to  
rpc calls much like a service would. That way others in the network can ask  
the streamer to subscribe to additional items, in turn it would close its  
long running http request and then re-open one with the additional items  
and start dispatching additional events. I could also ask it to shutdown  
etc.

Previously in pre-nameko I had basically rolled my own rpc server and  
greenlet forked the long running process and wired them up that way but I  
want to use nameko and cleanly.

I can only ever see 1 instance of this service running.. I'm struggling  
with the lifecycle of nameko.. should I create an extension.. should I  
create a custom container.. boing.. head hurts.

any ideas?

---

<div class="post-metadata">

**Author:** ![Stephen\_Foster](https://avatars.discourse-cdn.com/v4/letter/s/76d3ee/32.png) [@Stephen\_Foster](https://discourse.nameko.io/u/Stephen_Foster)\
**Post date:** [September 10, 2016, 11:15am UTC](https://discourse.nameko.io/t/long-running-http-polling-and-event-dispatch-and-how-to-move-it-to-nameko/152/2 "2016-09-10T11:15:11Z")

</div>

Ok.. re-reading [Key Concepts — nameko 2.11.0 documentation](http://nameko.readthedocs.io/en/latest/key_concepts.html)  
and moving  
towards [Writing Extensions — nameko 2.11.0 documentation](http://nameko.readthedocs.io/en/latest/writing_extensions.html#writing-extensions)

it looks like creating my own extension and entrypoint would be a good  
place to start. The entrypoint can fire the service method when new data  
arrives from the polling http.

I'll have to take a closer look and see if the entrypoints underlying is  
share across multiple services.. I don't want 2 long polling http's setup.

saturday talking to self because i didnt RTM, over and out 🙂

> **···**
>
> On Saturday, 10 September 2016 10:17:24 UTC+1, Stephen Foster wrote:
> 
> > Hi Guys (nameko + newbie = namekbie)
> > 
> > I've been messing with nameko for a very short while and I've thought it  
> > may be a great choice for what I want to do but I'm struggling with the  
> > best approach to perform something.
> > 
> > I currently have a class that opens a long running chunked http request  
> > and as chunks come down the line I want to emit an event ala pub/sub.  
> > Now I've managed to do this with a vanilla python class and creating a  
> > nameko event dispatcher in a stand alone mode(like in one of the examples).  
> > This does a great job of spitting out events as data comes down the long  
> > running http request.
> > 
> > Ideally.. (here is the rub) I would like that event streamer to respond  
> > to rpc calls much like a service would. That way others in the network can  
> > ask the streamer to subscribe to additional items, in turn it would close  
> > its long running http request and then re-open one with the additional  
> > items and start dispatching additional events. I could also ask it to  
> > shutdown etc.
> > 
> > Previously in pre-nameko I had basically rolled my own rpc server and  
> > greenlet forked the long running process and wired them up that way but I  
> > want to use nameko and cleanly.
> > 
> > I can only ever see 1 instance of this service running.. I'm struggling  
> > with the lifecycle of nameko.. should I create an extension.. should I  
> > create a custom container.. boing.. head hurts.
> > 
> > any ideas?

---

<div class="post-metadata">

**Author:** ![mattbennett](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.nameko.io/mattbennett/32/13_2.png) [@mattbennett](https://discourse.nameko.io/u/mattbennett)\
**Post date:** [September 22, 2016, 11:07am UTC](https://discourse.nameko.io/t/long-running-http-polling-and-event-dispatch-and-how-to-move-it-to-nameko/152/3 "2016-09-22T11:07:36Z")

</div>

Hi Stephen,

> Ok.. re-reading [Key Concepts — nameko 2.11.0 documentation](http://nameko.readthedocs.io/en/latest/key_concepts.html)  
> and moving towards  
> [Writing Extensions — nameko 2.11.0 documentation](http://nameko.readthedocs.io/en/latest/writing_extensions.html#writing-extensions)
> 
> it looks like creating my own extension and entrypoint would be a good  
> place to start. The entrypoint can fire the service method when new data  
> arrives from the polling http.

Yep, this is exactly the pattern you want.

> I'll have to take a closer look and see if the entrypoints underlying is  
> share across multiple services.. I don't want 2 long polling http's setup.

The WebServer class in nameko.web.server is a SharedExtension, meaning that  
if multiple entrypoints declare it they share the same instance. The whole  
of nameko.web is pretty small and should give you a decent idea where to  
start.

> saturday talking to self because i didnt RTM, over and out 🙂

🙂

Matt.

> **···**
>
> On Saturday, September 10, 2016 at 12:15:12 PM UTC+1, Stephen Foster wrote:
> 
> > On Saturday, 10 September 2016 10:17:24 UTC+1, Stephen Foster wrote:
> > 
> > > Hi Guys (nameko + newbie = namekbie)
> > > 
> > > I've been messing with nameko for a very short while and I've thought it  
> > > may be a great choice for what I want to do but I'm struggling with the  
> > > best approach to perform something.
> > > 
> > > I currently have a class that opens a long running chunked http request  
> > > and as chunks come down the line I want to emit an event ala pub/sub.  
> > > Now I've managed to do this with a vanilla python class and creating a  
> > > nameko event dispatcher in a stand alone mode(like in one of the examples).  
> > > This does a great job of spitting out events as data comes down the long  
> > > running http request.
> > > 
> > > Ideally.. (here is the rub) I would like that event streamer to respond  
> > > to rpc calls much like a service would. That way others in the network can  
> > > ask the streamer to subscribe to additional items, in turn it would close  
> > > its long running http request and then re-open one with the additional  
> > > items and start dispatching additional events. I could also ask it to  
> > > shutdown etc.
> > > 
> > > Previously in pre-nameko I had basically rolled my own rpc server and  
> > > greenlet forked the long running process and wired them up that way but I  
> > > want to use nameko and cleanly.
> > > 
> > > I can only ever see 1 instance of this service running.. I'm struggling  
> > > with the lifecycle of nameko.. should I create an extension.. should I  
> > > create a custom container.. boing.. head hurts.
> > > 
> > > any ideas?

---

<div class="post-metadata">

**Author:** ![Stephen\_Foster](https://avatars.discourse-cdn.com/v4/letter/s/76d3ee/32.png) [@Stephen\_Foster](https://discourse.nameko.io/u/Stephen_Foster)\
**Post date:** [September 22, 2016, 2:05pm UTC](https://discourse.nameko.io/t/long-running-http-polling-and-event-dispatch-and-how-to-move-it-to-nameko/152/4 "2016-09-22T14:05:17Z")

</div>

Hey Matt thanks for the response.

I actually ended up browsing the webserver and saw the shared extension code and such which put me on the path. Good to hear my approach was confirmed by you.

I created a shared extension for the polling and entry point with decorator etc. Then a simple streaming service that fired off events and responded to rpcs, delegating to the shared extension for subscriptions yada yada.

Short version is I read the docs again, scanned some examples and code and built something discovering in the process that nameko was doing loads of the hard work for me and it's extremely simple once you get your head around it.

Thanks for the tools and support  
Cheers Stephen.