RE: [MINA] Error on StreamIOHandler

[Irving, Dave]

DIRMINA-129 created to cover this issue. From: Irving, Dave [mailto:[EMAIL PROTECTED] Sent: 24 November 2005 17:55 To: Apache Directory Developers List Subject: RE: [MINA] Error on StreamIOHandler I can confirm that I've now reproduced this problem. Changing the ThreadPoolFilter keep-alive time changes the amount of time required before the exception is obvserved - so I think we got to the root cause (PipedInputStream doesn't like producer threads dying).   Possible solutions which spring to mind:   1) Mina could use its own "MinaPipedInput/OutputStream" or something. 2) A ThreadPoolFilter Worker thread could somehow know that it was logically still required even though it hadn't been active for a while (maybe a session attribute?). StreamIoHandler would then set this attribute on a write or something like that (and remove it onIdle / close whatever). This is quite a bit more hacky than (1).   Dave From: Jose Alberto Fernandez [mailto:[EMAIL PROTECTED] Sent: 24 November 2005 16:53 To: Apache Directory Developers List Subject: RE: [MINA] Error on StreamIOHandler Thanks Dave, now I understand the issue. Will see if you guys come with a smart solution before mocking with the thread parameters since we use several protocols and they all share the same threadfilter in the IoAcceptor.   Jose Alberto   From: Irving, Dave [mailto:[EMAIL PROTECTED] Sent: 24 November 2005 16:05 To: Apache Directory Developers List Subject: RE: [MINA] Error on StreamIOHandler   Expanding a bit on this:   ThreadPoolFilter has a default keep alive time of one minute. If no work comes in to the filter in this time (e.g because you haven't typed anything for a while), a worker thread could shut down.   So, in your example, the following could happen:   1) You write some data over telnet 2) A processor thread writes the data to the StreamIoHandlers PipedOutputStream 3) Your PipedInputStream reads the data. At this point, the processor thread is marked as the last writer (PipedInputStrea#writeSide). 4) You dont send any data for a while (so you are currently blocked in final String command = in.readLine(); in your code). 5) The processor thread idles out (default keep-alive time is one minute) 6) The PipedInputStream detects that the last writer thread is no longer alive and throws a "Pipe Broken" IOException 7) Your code writes this back to the client (in your catch block) 8) Your code closes the connection (your finally block)   I think thats probably whats happening.   To test my theory, try increasing the idle time out of the ThreadPoolFilter - you shouldn't get the exception until this time has elapsed (or decrease it, and observe the failure quicker).   So maybe we need to either use a custom piped stream in StreamIOHandler , or be careful with processor thread keep alives when using VM pipe?   Dave Dave           From: Jose Alberto Fernandez [mailto:[EMAIL PROTECTED] Sent: 24 November 2005 15:51 To: Apache Directory Developers List Subject: RE: [MINA] Error on StreamIOHandler Thanks, not sure if this is my case. As a matter of fact, the stack trace that I printed comes as part of the Telnet output just before the connection is closed.   This are some abstracts of the code loop of my worker thread:       protected void processStreamIo(IoSession i_ioSession, InputStream i_inputStream, OutputStream i_outputStream) {         try {             EXECUTOR_SERVICE.execute(new Worker(i_inputStream, i_outputStream));         } catch (IOException e) {             e.printStackTrace();             i_ioSession.close();         }     }           public Worker(final InputStream i_in, final OutputStream i_out) throws IOException {             in = new BufferedReader(new InputStreamReader( i_in ) );             out = new PrintWriter(new BufferedWriter( new OutputStreamWriter( i_out ) ), true);         }           public void run() {             try {                 while (true) {                     final String command = in.readLine();                     if (processCommand(command.trim())) {                         break;                     }                 }             } catch (IOException e) {                 e.printStackTrace(out);             } finally {                 out.close();             }         }   As you can see the stack trace is send to the telnet client before closing the connection.   From: Irving, Dave [mailto:[EMAIL PROTECTED] Sent: 24 November 2005 15:26 To: Apache Directory Developers List Subject: RE: [MINA] Error on StreamIOHandler   This is just a guess off the top of my head (so apologies if its wildly inaccurate), but I wonder whether it has anything to do with processor threads being shut down if they dont do any work? When an attempt is made to read from a PipedInputStream, a check is made every second to see whether the last thread to write to the associated PipedOutputStream is still alive.   From PipedInputStream:   int trials = 2;  while (in < 0) {      if (closedByWriter) {   /* closed by writer, return EOF */   return -1;      }      if ((writeSide != null) && (!writeSide.isAlive()) && (--trials < 0)) {   throw new IOException("Pipe broken");      }             /* might be a writer waiting */      notifyAll();      try {          wait(1000);      } catch (InterruptedException ex) {   throw new java.io.InterruptedIOException();      }   }   So, if mina shuts down the thread which caused the last write after inactivity (which I think it might do), this could be the cause. Dave   From: Jose Alberto Fernandez [mailto:[EMAIL PROTECTED] Sent: 24 November 2005 15:11 To: Apache Directory Developers List Subject: [MINA] Error on StreamIOHandler Hi, we are getting the following stack trace when one is not constantly typing on a telnet session connected using StreamIOHandler:   java.io.IOException: Pipe broken         at java.io.PipedInputStream.read(PipedInputStream.java:255)         at org.apache.mina.io.handler.StreamIoHandler$PipedInputStream.read(StreamIoHandler.java:223)         at java.io.PipedInputStream.read(PipedInputStream.java:305)         at org.apache.mina.io.handler.StreamIoHandler$PipedInputStream.read(StreamIoHandler.java:229)         at sun.nio.cs.StreamDecoder$CharsetSD.readBytes(StreamDecoder.java:411)         at sun.nio.cs.StreamDecoder$CharsetSD.implRead(StreamDecoder.java:453)         at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:183)         at java.io.InputStreamReader.read(InputStreamReader.java:167)         at java.io.BufferedReader.fill(BufferedReader.java:136)         at java.io.BufferedReader.readLine(BufferedReader.java:299)         at java.io.BufferedReader.readLine(BufferedReader.java:362)         at com.cellectivity.poker.clienthandler.telnet.PokerTelnetHandler$Worker.run(PokerTelnetHandler.java:340)         at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:650)         at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:675)         at java.lang.Thread.run(Thread.java:595)   This is MINA 0.8.1. We have only one connection and this occurs every time we do not use the telnet session for a little while, less than a minute. Has anyone seen this error before? Any way to solve it?   Jose Alberto     This e-mail and any attachment is for authorised use by the intended recipient(s) only. It may contain proprietary material, confidential information and/or be subject to legal privilege. It should not be copied, disclosed to, retained or used by, any other party. If you are not an intended recipient then please promptly delete this e-mail and any attachment and all copies and inform the sender. Thank you.