[SOLVED] StopAccepting() method not stopping TSocketServer.
lazarus / 38-Networking and Web Programming

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zamronypj · 2019-07-03 13:13

When use blocking, StartAccepting() method of TSocketServer will not
exit until its internal variable FAccepting is false. Calling
StopAccepting outside this loop is useless. All sample applications,
for example
https://github.com/graemeg/freepascal/blob/master/packages/fcl-
base/examples/dsocksvr.pp, call StopAccepting inside OnConnect().

However, OnConnect() will be called only if there are data available.
If there is no data available, then, stopAccepting may never be
called. We can force to terminate application by sending
SIGTERM/SIGINT signal, but that cause application is terminated
immediately without opportunity to do some cleanup (closing open
files, deleting temporary files etc).

How to gracefully shutdown TSocketServer?

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zamronypj · 2019-07-13 08:42

I solved it by implementing my own socket server (Unix only). Just in
case anyone interested, here is the link

https://github.com/fanoframework/fano/blob/master/src/Libs/Socket/Sock
etSvrImpl.pas
https://github.com/fanoframework/fano/blob/master/src/Libs/Socket/Unix
SocketSvrImpl.pas
https://github.com/fanoframework/fano/blob/master/src/Libs/Socket/Inet
SocketSvrImpl.pas

I need to be able to gracefully exiting, to be able to view heaptrc
output to analyze if there are any memory leak. Any feedback for
improvement are welcome.

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GDean · 2019-08-09 03:51

Quote from: zamronypj on July 13, 2019, 10:42:46 amI solved it by
implementing my own socket server (Unix only). Just in case anyone
interested, here is the link

https://github.com/fanoframework/fano/blob/master/src/Libs/Socket/Sock
etSvrImpl.pas
https://github.com/fanoframework/fano/blob/master/src/Libs/Socket/Unix
SocketSvrImpl.pas
https://github.com/fanoframework/fano/blob/master/src/Libs/Socket/Inet
SocketSvrImpl.pas

I need to be able to gracefully exiting, to be able to view heaptrc
output to analyze if there are any memory leak. Any feedback for
improvement are welcome.

SocketSvrImpl has RunnableIntf, RunnableWithDataNotifIntf,
DataAvailListenerIntf, StreamAdapterIntf in uses can you upload those
to GitHub

thanks gd

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lucamar · 2019-08-09 04:59

Quote from: zamronypj on July 03, 2019, 03:13:43 pmWe can force to
terminate application by sending SIGTERM/SIGINT signal, but that cause
application is terminated immediately without opportunity to do some
cleanup (closing open files, deleting temporary files etc).

How to gracefully shutdown TSocketServer?

Didn't see this before, sorry. For some reason the default application
object doesn't react to signals but you can use fpSigAction to add
your own signal handler to react to almost any signal, the exceptions
being SIGKILL and SIGSTOP.

I see you already solved it but for completeness sake I have attached
a program I did to test this. For your use case note particularly the
"special" treatment of SIGTERM in HandleSignal / GracefulExit.

Regards.

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zamronypj · 2019-08-09 10:37

@GDean, they are all in github. It is implemented to fit Fano
Framework requirement so it may not fit your use case.

@lucamar yes, fpSigAction() that is what I end up using in my own
implementation.