julien greard created THRIFT-5547:
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Summary: C++ - Can't interrupt the handler on the server side
while using TMultiplexedProcessor in case of client deconnection
Key: THRIFT-5547
URL: https://issues.apache.org/jira/browse/THRIFT-5547
Project: Thrift
Issue Type: Brainstorming
Components: C++ - Library
Affects Versions: 0.16.0
Reporter: julien greard
Hello,
I have the following architecture in my code:
* 1 thrift Server
* 1 thrift MultiplexedProcessor
* several Services & associated processors/handlers
* N thrift clients (several by processor/handler)
* 1 queue which contains the tasks asked by the clients
What I*really*want is to be able cancel a task when a client crashes.
Let me explain:
Let's say I have the following service handler method :
|// inside thrift handler // this method is currently instanciated once and
called by every client void do_stuff(const std::string& parameter) \{ auto task
= make_task(parameter); auto future_result = task .get_future();
add_to_queue(task); auto status = resultFuture.wait_for(timeout); // wait here
until the task is over if (status != std::future_status::timeout) { return
future_result.get(); } } |
If the client crashes/disconnects, there is no need to process with the task
anymore, so I would like to cancel it (remove from my queue) asap.
To do so, I had the following ideas:
1/ Using the*setServerEventHandler*method from my Thrift Server to be notified
when a client disconnects (deleteContext method). It works very well but I am
not able to know which request was made by which specific client: within my
handler I do not have access to the client infos, and I can't use (or didnt
managed to) the void * context created by the method creatContext in my
ServerEventHandler
2/ Using the contructor & destructor of my handler object to link 1 client to 1
handler. Then when the client disconnects, I only have to cancel every task he
asked in the handler destructor. Currently I have N client and 1 handler, so it
doesn't work. I figured I could use a TMultiplexedProcessorFactory but there is
no such class in thrift. The TMultiplexedProcessor has to register Processor
(with single handler) when I'd like to register a Factory which will create one
handler instance by client. I could implement my own
TMultiplexedProcessorFactory but I think there might be a good reason this
doesn't exist yet.
Any idea of what I should do ?
I can post it inhttps://issues.apache.org/but it's not exactly an issue with
thrift (great lib btw), rather than a question.
Thanks in advance, don't hesitate to ask for more details
This post is a duplicate of a StackOverflow question I asked last Friday
[<https://stackoverflow.com/questions/71707726/using-a-processor-factory-with-tmultiplexedprocessor-in-thrift>|https://stackoverflow.com/questions/71707726/using-a-processor-factory-with-tmultiplexedprocessor-in-thrift]
Thanks in advance,
Julien Greard
There has been an answer to this request in
[dev@thrift.apache.org|mailto:dev@thrift.apache.org] : the user Yuxuan Wang has
described having the same issue in Go and he solved it by adding a context to
the handler services + a thread watchding regularly the opened sockets
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