[vwnc] SocketAccessor>>accept blocks image?
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[vwnc] SocketAccessor>>accept blocks image?
 
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Re: [vwnc] SocketAccessor>>accept blocks image?
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Oops,I forgot to
include the attachment. Here it is. From: [hidden email]
[mailto:[hidden email]] On Behalf Of Philippe Demaecker Hello list, One of our customers is reporting a problem
where working with web services/SOAP blocks the image (more particularly when a
SOAP proxy is trying to accept connections. This hanging seems to last forever
until a ctrl-y is performed. This seems to ‘kick-start’ the image, and the
application will run smoothly again for a while. 1.
Our setup is as follows… We have our own application acting as a
SOAP client which sends SOAP calls to a (non-Smalltalk) web service somewhere
on a local network. We make a SOAP call from a class named
ABCService, so first we create and start proxy ABCInterfaceSoapProxy (a
WSOpentalkClient subclass). To this proxy we send the message
getABCInformation:forDomain: which forwards this message to the web service. A
new proxy is created each time we make a soap call. While tracing I noticed that: . BasicObjectAdapto>>sendRequest:
creates a new connection with the server and exchanges information through this
connection: ok, works as expected. . BUT: for some reason, when starting the
proxy (WSOpentalkClient>>start), it prepares itself to act as a server
and accept incoming connections (ConnectionListener>>doStart) on IP
0.0.0.0:PORT (Why is this necessary?) 2.
I suspect that the hanging
starts once the proxy starts to listen to incoming connects, more specifically,
when SocketAccessor>>primAccept encounters a EWOULDBLOCK, which I think,
raises a OSErrorHolder notReadySignal. I can reproduce this hanging by having
SocketAccessor>>primAccept raise an OSErrorHolder notReadySignal
explicitely: primAccept OSErrorHolder
notReadySignal raise. but I could not find a scenario where this
EWOULDBLOCK is thrown by the primitive call. You can experience the blocking it yourself
starting a WSOpentalkClient client (.st file attached), overwriting primAccept
with: primAccept OSErrorHolder
notReadySignal raise. and then trying to connecting to the OT
client with: ws := WSOpentalkTestClient new start. sktClient1 := SocketAccessor
newTCPclientToHost: 'localhost' port: WSOpentalkTestClient port. sktClient1 close. ws stop. 3.
Below you can find 2 stack
traces created by a ctrl-y at a moment the image was blocking. Stack 1: it seems that
SocketAccessor>>primAccept runs into an (EWouldBlock) error trying to
report it, but blocking the image. Stack 2: the proxy setting up its listener
process So, I have a few questions: 1.
Why is the proxy starting a
listener process? I don’t understand we this is necessary when communication
between Client and server happens using the sendRequest:? What am I missing? 2.
How can I create a situation
where primAccept would return a EWOULDBLOCK error? 3.
Why is raising a EWOULDBLOCK in
primAccept blocking the image? My network knowledge is limited, so please
be forgiving if I made mistakes in my assumptions above. Thanks in advance for your advice, Philippe ------------------------------------------------------------ Active Process Context Stack: [1]
Dictionary(Set)>>initialIndexFor:boundedBy: [2]
Dictionary>>findKeyOrNil: [3]
Dictionary>>at:ifAbsent: [4]
SocketAccessor
class(OSErrorHolder class)>>reportProceedingOn: [5]
SocketAccessor(OSErrorHolder)>>reportError [6]
SocketAccessor>>primAccept [7]
optimized [] in
SocketAccessor>>accept [8]
optimized [] in OSHandle
class>>handleValue: [9]
optimized [] in
HandleRegistry>>registerValueOf: [10]
BlockClosure>>ensure: [11]
optimized [] in RecursionLock>>critical: [12]
BlockClosure>>ensure: [13]
Semaphore>>critical: [14]
RecursionLock>>critical: [15]
optimized [] in HandleRegistry>>evaluateWithFullProtection: [16]
BlockClosure>>on:do: [17]
HandleRegistry>>evaluateWithFullProtection: [18]
HandleRegistry>>registerValueOf: [19]
SocketAccessor class(OSHandle class)>>handleValue: [20]
SocketAccessor>>accept [21]
optimized [] in Opentalk.ConnectionListener>>listenerProcessBody [22]
BlockClosure>>on:do: [23]
Opentalk.ConnectionListener>>listenerProcessBody [24]
optimized [] in [] in Opentalk.ConnectionListener>>startListenerProcess [25]
BlockClosure>>on:do: [26]
optimized [] in Process class>>forBlock:priority: ------------------------------------------------------------ Quiescent Processes Process priority: 30 (id=8615) Context Stack: [1]
Process>>resume [2]
BlockClosure>>forkAt: [3]
optimized [] in
Opentalk.ConnectionListener>>startListenerProcess [4]
UndefinedObject(MediaGeniX.BLABLABLAClass class)>>ifNotAssigned: [5]
Opentalk.ConnectionListener>>startListenerProcess [6]
optimized [] in
Opentalk.ConnectionListener>>doStart [7]
BlockClosure>>ifCurtailed: [8]
Opentalk.ConnectionListener>>doStart [9]
Opentalk.ConnectionListener(Opentalk.GenericProtocol)>>start [10]
Opentalk.AsymmetricConnectionAdaptor(Opentalk.ConnectionAdaptor)>>startServer [11]
Opentalk.AsymmetricConnectionAdaptor(Opentalk.BasicObjectAdaptor)>>doStart [12]
Opentalk.AsymmetricConnectionAdaptor(Opentalk.GenericProtocol)>>start [13]
Opentalk.BasicRequestBroker>>doStart [14]
Opentalk.BasicRequestBroker(Opentalk.GenericProtocol)>>start [15] MediaGeniX.ABCInterfaceSoapProxy(Opentalk.WSOpentalkClient)>>start [23]
MediaGeniX. ABCService (Smalltalk.UI.Model)>>getABCInformation:forDomain: _______________________________________________ vwnc mailing list [hidden email] http://lists.cs.uiuc.edu/mailman/listinfo/vwnc |
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