Exemplo n.º 1
0
    private void sendAck() {
      // Send results back
      DTask dt, origDt = _dt; // _dt can go null the instant it is send over wire
      assert origDt != null; // Freed after completion
      while ((dt = _dt) != null) { // Retry loop for broken TCP sends
        AutoBuffer ab = null;
        try {
          // Start the ACK with results back to client.  If the client is
          // asking for a class/id mapping (or any job running at FETCH_ACK
          // priority) then return a udp.fetchack byte instead of a udp.ack.
          // The receiver thread then knows to handle the mapping at the higher
          // priority.

          UDP.udp udp = dt.priority() == H2O.FETCH_ACK_PRIORITY ? UDP.udp.fetchack : UDP.udp.ack;
          ab = new AutoBuffer(_client, udp._prior).putTask(udp, _tsknum).put1(SERVER_UDP_SEND);
          assert ab.position() == 1 + 2 + 4 + 1;
          dt.write(ab); // Write the DTask - could be very large write
          dt._repliedTcp = ab.hasTCP(); // Resends do not need to repeat TCP result
          ab.close(); // Then close; send final byte
          _computedAndReplied = true; // After the final handshake, set computed+replied bit
          break; // Break out of retry loop
        } catch (AutoBuffer.AutoBufferException e) {
          if (!_client._heartbeat._client) // Report on servers only; clients allowed to be flaky
          Log.info(
                "IOException during ACK, "
                    + e._ioe.getMessage()
                    + ", t#"
                    + _tsknum
                    + " AB="
                    + ab
                    + ", waiting and retrying...");
          ab.drainClose();
          if (_client._heartbeat._client) // Dead client will not accept a TCP ACK response?
          this.CAS_DT(dt, null); // cancel the ACK
          try {
            Thread.sleep(100);
          } catch (InterruptedException ignore) {
          }
        } catch (Exception e) { // Custom serializer just barfed?
          Log.err(e); // Log custom serializer exception
          ab.drainClose();
        }
      } // end of while(true)
      if (dt == null)
        Log.info(
            "Cancelled remote task#"
                + _tsknum
                + " "
                + origDt.getClass()
                + " to "
                + _client
                + " has been cancelled by remote");
      else {
        if (dt instanceof MRTask && dt.logVerbose())
          Log.debug("Done remote task#" + _tsknum + " " + dt.getClass() + " to " + _client);
        _client.record_task_answer(this); // Setup for retrying Ack & AckAck, if not canceled
      }
    }
Exemplo n.º 2
0
 // Re-send strictly the ack, because we're missing an AckAck
 final void resend_ack() {
   assert _computedAndReplied : "Found RPCCall not computed " + _tsknum;
   DTask dt = _dt;
   if (dt == null) return; // Received ACKACK already
   UDP.udp udp = dt.priority() == H2O.FETCH_ACK_PRIORITY ? UDP.udp.fetchack : UDP.udp.ack;
   AutoBuffer rab = new AutoBuffer(_client, dt.priority()).putTask(udp, _tsknum);
   boolean wasTCP = dt._repliedTcp;
   if (wasTCP) rab.put1(RPC.SERVER_TCP_SEND); // Original reply sent via TCP
   else {
     rab.put1(RPC.SERVER_UDP_SEND); // Original reply sent via UDP
     assert rab.position() == 1 + 2 + 4 + 1;
     dt.write(rab);
   }
   assert sz_check(rab)
       : "Resend of " + _dt.getClass() + " changes size from " + _size + " to " + rab.size();
   assert dt._repliedTcp == wasTCP;
   rab.close();
   dt._repliedTcp = wasTCP;
   // Double retry until we exceed existing age.  This is the time to delay
   // until we try again.  Note that we come here immediately on creation,
   // so the first doubling happens before anybody does any waiting.  Also
   // note the generous 5sec cap: ping at least every 5 sec.
   _retry += (_retry < MAX_TIMEOUT) ? _retry : MAX_TIMEOUT;
 }
Exemplo n.º 3
0
  public synchronized RPC<V> call() {
    // Any Completer will not be carried over to remote; add it to the RPC call
    // so completion is signaled after the remote comes back.
    CountedCompleter cc = _dt.getCompleter();
    if (cc != null) handleCompleter(cc);

    // If running on self, just submit to queues & do locally
    if (_target == H2O.SELF) return handleLocal();

    // Keep a global record, for awhile
    if (_target != null) _target.taskPut(_tasknum, this);
    try {
      if (_nack) return this; // Racing Nack rechecked under lock; no need to send retry
      // We could be racing timeouts-vs-replies.  Blow off timeout if we have an answer.
      if (isDone()) {
        if (_target != null) _target.taskRemove(_tasknum);
        return this;
      }
      // Default strategy: (re)fire the packet and (re)start the timeout.  We
      // "count" exactly 1 failure: just whether or not we shipped via TCP ever
      // once.  After that we fearlessly (re)send UDP-sized packets until the
      // server replies.

      // Pack classloader/class & the instance data into the outgoing
      // AutoBuffer.  If it fits in a single UDP packet, ship it.  If not,
      // finish off the current AutoBuffer (which is now going TCP style), and
      // make a new UDP-sized packet.  On a re-send of a TCP-sized hunk, just
      // send the basic UDP control packet.
      if (!_sentTcp) {
        while (true) { // Retry loop for broken TCP sends
          AutoBuffer ab = new AutoBuffer(_target, _dt.priority());
          try {
            final boolean t;
            int offset = ab.position();
            ab.putTask(UDP.udp.exec, _tasknum).put1(CLIENT_UDP_SEND);
            ab.put(_dt);
            t = ab.hasTCP();
            assert sz_check(ab)
                : "Resend of "
                    + _dt.getClass()
                    + " changes size from "
                    + _size
                    + " to "
                    + ab.size()
                    + " for task#"
                    + _tasknum;
            ab.close(); // Then close; send final byte
            _sentTcp = t; // Set after close (and any other possible fail)
            break; // Break out of retry loop
          } catch (AutoBuffer.AutoBufferException e) {
            Log.info(
                "IOException during RPC call: "
                    + e._ioe.getMessage()
                    + ",  AB="
                    + ab
                    + ", for task#"
                    + _tasknum
                    + ", waiting and retrying...");
            ab.drainClose();
            try {
              Thread.sleep(500);
            } catch (InterruptedException ignore) {
            }
          }
        } // end of while(true)
      } else {
        // Else it was sent via TCP in a prior attempt, and we've timed out.
        // This means the caller's ACK/answer probably got dropped and we need
        // him to resend it (or else the caller is still processing our
        // request).  Send a UDP reminder - but with the CLIENT_TCP_SEND flag
        // instead of the UDP send, and no DTask (since it previously went via
        // TCP, no need to resend it).
        AutoBuffer ab = new AutoBuffer(_target, _dt.priority()).putTask(UDP.udp.exec, _tasknum);
        ab.put1(CLIENT_TCP_SEND).close();
      }
      // Double retry until we exceed existing age.  This is the time to delay
      // until we try again.  Note that we come here immediately on creation,
      // so the first doubling happens before anybody does any waiting.  Also
      // note the generous 5sec cap: ping at least every 5 sec.
      _retry += (_retry < MAX_TIMEOUT) ? _retry : MAX_TIMEOUT;
      // Put self on the "TBD" list of tasks awaiting Timeout.
      // So: dont really 'forget' but remember me in a little bit.
      //      UDPTimeOutThread.PENDING.put(_tasknum, this);
      return this;
    } catch (Throwable t) {
      t.printStackTrace();
      throw Log.throwErr(t);
    }
  }