Github user pwendell commented on a diff in the pull request:
https://github.com/apache/spark/pull/247#discussion_r11234823
--- Diff:
streaming/src/main/scala/org/apache/spark/streaming/dstream/NetworkInputDStream.scala
---
@@ -124,84 +143,109 @@ abstract class NetworkReceiver[T: ClassTag]()
extends Serializable with Logging
receivingThread
// Call user-defined onStart()
+ logInfo("Calling onStart")
onStart()
+
+ // Wait until interrupt is called on this thread
+ while(true) Thread.sleep(100000)
} catch {
case ie: InterruptedException =>
- logInfo("Receiving thread interrupted")
- //println("Receiving thread interrupted")
+ logInfo("Receiving thread has been interrupted, receiver " +
streamId + " stopped")
case e: Exception =>
- stopOnError(e)
+ logError("Error receiving data in receiver " + streamId, e)
+ exceptions += e
+ }
+
+ // Call user-defined onStop()
+ logInfo("Calling onStop")
+ try {
+ onStop()
+ } catch {
+ case e: Exception =>
+ logError("Error stopping receiver " + streamId, e)
+ exceptions += e
+ }
+
+ val message = if (exceptions.isEmpty) {
+ null
+ } else if (exceptions.size == 1) {
+ val e = exceptions.head
+ "Exception in receiver " + streamId + ": " + e.getMessage + "\n" +
e.getStackTraceString
+ } else {
+ "Multiple exceptions in receiver " + streamId + "(" +
exceptions.size + "):\n"
+ exceptions.zipWithIndex.map {
+ case (e, i) => "Exception " + i + ": " + e.getMessage + "\n" +
e.getStackTraceString
+ }.mkString("\n")
}
+ logInfo("Deregistering receiver " + streamId)
+ val future = trackerActor.ask(DeregisterReceiver(streamId,
message))(askTimeout)
+ Await.result(future, askTimeout)
+ logInfo("Deregistered receiver " + streamId)
+ env.actorSystem.stop(actor)
+ logInfo("Stopped receiver " + streamId)
}
/**
- * Stops the receiver. First it interrupts the main receiving thread,
+ * Stop the receiver. First it interrupts the main receiving thread,
* that is, the thread that called receiver.start(). Then it calls the
user-defined
* onStop() method to stop other threads and/or do cleanup.
*/
def stop() {
+ // Stop receiving by interrupting the receiving thread
receivingThread.interrupt()
--- End diff --
This is a bit confusing - is the receivingThread assumed to be running user
code or is the assumption that it's sleeping in the `Thread.sleep(` line? I
think it would simplify things a lot if you could assume that `onStart` doesn't
block.
Also, could you have a condition variable here instead of using
sleep/interruption?
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