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Bug #6369

closed

GServer blocking after shutdown called

Added by stevegoobermanhill (stephen gooberman-hill) almost 12 years ago. Updated about 6 years ago.

Status:
Closed
Target version:
-
ruby -v:
ruby 1.9.2p290 (2011-07-09 revision 32553) [i686-linux]
[ruby-core:44666]

Description

Hi,
My investigation of bug #6358 points the finger at GServer triggering bug #5343 on lower power arm-linux platforms, because of the blocking TCPServer#accept call.

I believe there is also an underlying design flaw: the main thread (@tcpServerThread) is blocked in the TCPServer#accept call, so if no further connections are attempted after #shutdown() is called, the main thread remains blocked and will hang until it is forced into the ensure clause by the destruction of the GServer object by GC

This proposed patch to GServer seems to tackle the first issue, and also effectively makes the TCPServer#accept nonblocking by using a Timeout block to ensure that the main thread periodically (every 0.1s) has the chance to shut down gracefully if no further connections are forthcoming.

It also adds a GServer#shutdown! method which will block until the GServer has gracefully shut down

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< # server.shutdown
< #

server.shutdown #will not wait for the server thread to quit

server.shutdown! #blocks until server thread has quit

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<

def shutdown!
shutdown
while !stopped?
sleep 0.01
end
end

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< @@servicesMutex.synchronize {

@@servicesMutex.synchronize do

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< }
< @tcpServerThread = Thread.new {

end

@tcpServerThread = Thread.new do

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< @connectionsMutex.synchronize {

      @connectionsMutex.synchronize do

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< }
< client = @tcpServer.accept
< @connections << Thread.new(client) { |myClient|
< begin
< myPort = myClient.peeraddr[1]
< serve(myClient) if @audit or connecting(myClient)
< rescue => detail
< error(detail) if @debug
< ensure
< begin
< myClient.close
< rescue

      end
      
      
      begin
        Timeout::timeout(0.1) do 
          client = @tcpServer.accept
     
          @connections << Thread.new(client) do |myClient|
            begin
              myPort = myClient.peeraddr[1]
              serve(myClient) if !@audit or connecting(myClient)
            rescue => detail
              error(detail) if @debug
            ensure
              begin
                myClient.close
                sleep 1
              rescue
              end
              @connectionsMutex.synchronize do
                @connections.delete(Thread.current)
                @connectionsCV.signal
              end
              disconnecting(myPort) if @audit
            end

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< @connectionsMutex.synchronize {
< @connections.delete(Thread.current)
< @connectionsCV.signal
< }
< disconnecting(myPort) if @audit
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< }

     rescue Timeout::Error
     end

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< @connectionsMutex.synchronize {

      @connectionsMutex.synchronize do

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< }

      end

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< @@servicesMutex.synchronize {

    @@servicesMutex.synchronize do

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< }

    end

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< }

end
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