Re: Socket - handling large numbers of incoming connections

[Johannes Pfau via Digitalmars-d-learn]

Am Mon, 21 Dec 2015 23:29:14 +
schrieb Adam D. Ruppe :

> On Monday, 21 December 2015 at 23:17:45 UTC, Daniel Kozák wrote:
> > If you want to reinvent the wheel you can use  
> 
> [...] it isn't like the bundled functions with the OS are 
> hard to use [...]
> 

epoll and similar interfaces are not difficult to use. But you
need to be careful to handle all error conditions caused by low level
posix io calls (read/write) correctly. (Partial reads/writes, How
do you handle EINTR? How do you handle error codes returned by the close
function*? ...)

* http://lwn.net/Articles/576478/

Re: Socket - handling large numbers of incoming connections

[Jakob Jenkov via Digitalmars-d-learn]

The same as in C [1].
Just change
#include 
to
import core.sys.posix.poll;

[1] http://linux.die.net/man/2/poll



I have a background in Java, so I am a bit handicapped :-)

Re: Socket - handling large numbers of incoming connections

[Jakob Jenkov via Digitalmars-d-learn]

Thanks, everyone, I have looked a bit at different frameworks, 
and it seems that libasync might have a decently narrow scope to 
fit what I need.


I have a background in Java, so a lot of this OS-specific stuff 
is new to me (EPoll etc.). In Java that stuff is used under the 
hood for you, without you knowing anything about it. Java just 
chooses the best option for the given OS. This is easy to use, 
but of course gives you less control.

Socket - handling large numbers of incoming connections

[Jakob Jenkov via Digitalmars-d-learn]

What is the fastest / most scalable way to implement a server 
(using a Socket) which can handle large numbers of incoming 
connections? Like, at least 10K, but probably up to 1 million 
connections.


More specifically:

1) How do I efficiently select the connections (client Socket 
instances) which have data which is ready to read?


2) How do I efficiently select the connection that are ready to 
accept data sent to them?

(which are write ready - in other words) ?


I read in the D Cookbook that using the SocketSet is not the 
fastest way to do this, as it has to iterate through all Socket 
instances in it, and check a flag on each Socket.

Re: Socket - handling large numbers of incoming connections

[Stefan via Digitalmars-d-learn]

How about https://github.com/dcarp/asynchronous ? Asyncio Socket 
handling is sometimes quite nice. It's performance is okay for 
nearly no effort and the code looks clean.
Details here: 
http://dcarp.github.io/asynchronous/asynchronous/streams/startServer.html


vibe.d also offers a fiber based asyncio way of dealing with 
sockets.

http://vibed.org/docs#tcp-server

Maybe it fits your needs.

Re: Socket - handling large numbers of incoming connections

[Jakob Jenkov via Digitalmars-d-learn]

On Monday, 21 December 2015 at 20:20:44 UTC, Stefan wrote:
How about https://github.com/dcarp/asynchronous ? Asyncio 
Socket handling is sometimes quite nice. It's performance is 
okay for nearly no effort and the code looks clean.
Details here: 
http://dcarp.github.io/asynchronous/asynchronous/streams/startServer.html


vibe.d also offers a fiber based asyncio way of dealing with 
sockets.

http://vibed.org/docs#tcp-server

Maybe it fits your needs.


Thanks - but I am primarily looking for a solution without 
external frameworks. Frameworks have a way of bloating over time.

Re: Socket - handling large numbers of incoming connections

[Jakob Jenkov via Digitalmars-d-learn]

My server uses "poll" for that.


Okay, how does that work? How do I use "poll" in D?

Link?
Code example?

Re: Socket - handling large numbers of incoming connections

[tcak via Digitalmars-d-learn]

On Monday, 21 December 2015 at 20:53:14 UTC, Jakob Jenkov wrote:

On Monday, 21 December 2015 at 20:20:44 UTC, Stefan wrote:
How about https://github.com/dcarp/asynchronous ? Asyncio 
Socket handling is sometimes quite nice. It's performance is 
okay for nearly no effort and the code looks clean.
Details here: 
http://dcarp.github.io/asynchronous/asynchronous/streams/startServer.html


vibe.d also offers a fiber based asyncio way of dealing with 
sockets.

http://vibed.org/docs#tcp-server

Maybe it fits your needs.


Thanks - but I am primarily looking for a solution without 
external frameworks. Frameworks have a way of bloating over 
time.


My server uses "poll" for that.

Re: Socket - handling large numbers of incoming connections

[Daniel Kozák via Digitalmars-d-learn]

V Mon, 21 Dec 2015 20:53:14 +
Jakob Jenkov via Digitalmars-d-learn
 napsáno:

> On Monday, 21 December 2015 at 20:20:44 UTC, Stefan wrote:
> > How about https://github.com/dcarp/asynchronous ? Asyncio 
> > Socket handling is sometimes quite nice. It's performance is 
> > okay for nearly no effort and the code looks clean.
> > Details here: 
> > http://dcarp.github.io/asynchronous/asynchronous/streams/startServer.html
> >
> > vibe.d also offers a fiber based asyncio way of dealing with 
> > sockets.
> > http://vibed.org/docs#tcp-server
> >
> > Maybe it fits your needs.  
> 
> Thanks - but I am primarily looking for a solution without 
> external frameworks. Frameworks have a way of bloating over time.

Use vibe.d or other library for async io (libasync). If you want to
reinvent the wheel you can use
kqueue(https://github.com/D-Programming-Language/druntime/blob/1f957372e5dadb92ab1d621d68232dbf8a2dbccf/src/core/sys/freebsd/sys/event.d)
for bsd,
epoll(https://github.com/D-Programming-Language/druntime/blob/master/src/core/sys/linux/epoll.d)
for linux and "I do not use windows" for windows.

Re: Socket - handling large numbers of incoming connections

[Adam D. Ruppe via Digitalmars-d-learn]

On Monday, 21 December 2015 at 23:17:45 UTC, Daniel Kozák wrote:

If you want to reinvent the wheel you can use


It isn't really reinventing the wheel to just use an alternate 
library... it isn't like the bundled functions with the OS are 
hard to use and you really should understand how they work anyway 
to write efficient programs.

Re: Socket - handling large numbers of incoming connections

[Adrian Matoga via Digitalmars-d-learn]

On Monday, 21 December 2015 at 21:32:55 UTC, Jakob Jenkov wrote:

My server uses "poll" for that.


Okay, how does that work? How do I use "poll" in D?

Link?
Code example?


The same as in C [1].
Just change
#include 
to
import core.sys.posix.poll;

[1] http://linux.die.net/man/2/poll

Re: Socket - handling large numbers of incoming connections

[Daniel Kozak via Digitalmars-d-learn]

V Mon, 21 Dec 2015 23:29:14 +
"Adam D. Ruppe via Digitalmars-d-learn"
 napsáno:

> On Monday, 21 December 2015 at 23:17:45 UTC, Daniel Kozák wrote:
> > If you want to reinvent the wheel you can use  
> 
> It isn't really reinventing the wheel to just use an alternate 
> library...
I guess you are right

> it isn't like the bundled functions with the OS are 
> hard to use and you really should understand how they work anyway 

I agree, if something go wrong it is a nice to know why

> to write efficient programs.
>

I can write efficient programs with vibe.d(libevent,libuv,libasync...)
too :).