[SPARK-9844][CORE] File appender race condition during shutdown

When an Executor process is destroyed, the FileAppender that is asynchronously reading the stderr stream of the process can throw an IOException during read because the stream is closed. Before the ExecutorRunner destroys the process, the FileAppender thread is flagged to stop. This PR wraps the inputStream.read call of the FileAppender in a try/catch block so that if an IOException is thrown and the thread has been flagged to stop, it will safely ignore the exception. Additionally, the FileAppender thread was changed to use Utils.tryWithSafeFinally to better log any exception that do occur. Added unit tests to verify a IOException is thrown and logged if FileAppender is not flagged to stop, and that no IOException when the flag is set. Author: Bryan Cutler <[email protected]> Closes apache#10714 from BryanCutler/file-appender-read-ioexception-SPARK-9844.
jjallaire · Jan 14, 2016 · 56cdbd6 · 56cdbd6
1 parent 8f13cd4
commit 56cdbd6
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diff --git a/core/src/main/scala/org/apache/spark/util/logging/FileAppender.scala b/core/src/main/scala/org/apache/spark/util/logging/FileAppender.scala
@@ -17,7 +17,7 @@
 
 package org.apache.spark.util.logging
 
-import java.io.{File, FileOutputStream, InputStream}
+import java.io.{File, FileOutputStream, InputStream, IOException}
 
 import org.apache.spark.{Logging, SparkConf}
 import org.apache.spark.util.{IntParam, Utils}
@@ -58,20 +58,28 @@ private[spark] class FileAppender(inputStream: InputStream, file: File, bufferSi
   protected def appendStreamToFile() {
     try {
       logDebug("Started appending thread")
-      openFile()
-      val buf = new Array[Byte](bufferSize)
-      var n = 0
-      while (!markedForStop && n != -1) {
-        n = inputStream.read(buf)
-        if (n != -1) {
-          appendToFile(buf, n)
+      Utils.tryWithSafeFinally {
+        openFile()
+        val buf = new Array[Byte](bufferSize)
+        var n = 0
+        while (!markedForStop && n != -1) {
+          try {
+            n = inputStream.read(buf)
+          } catch {
+            // An InputStream can throw IOException during read if the stream is closed
+            // asynchronously, so once appender has been flagged to stop these will be ignored
+            case _: IOException if markedForStop =>  // do nothing and proceed to stop appending
+          }
+          if (n > 0) {
+            appendToFile(buf, n)
+          }
         }
+      } {
+        closeFile()
       }
     } catch {
       case e: Exception =>
         logError(s"Error writing stream to file $file", e)
-    } finally {
-      closeFile()
     }
   }
 

diff --git a/core/src/test/scala/org/apache/spark/util/FileAppenderSuite.scala b/core/src/test/scala/org/apache/spark/util/FileAppenderSuite.scala
@@ -18,12 +18,17 @@
 package org.apache.spark.util
 
 import java.io._
+import java.util.concurrent.CountDownLatch
 
 import scala.collection.mutable.HashSet
 import scala.reflect._
 
 import com.google.common.base.Charsets.UTF_8
 import com.google.common.io.Files
+import org.apache.log4j.{Appender, Level, Logger}
+import org.apache.log4j.spi.LoggingEvent
+import org.mockito.ArgumentCaptor
+import org.mockito.Mockito.{atLeast, mock, verify}
 import org.scalatest.BeforeAndAfter
 
 import org.apache.spark.{Logging, SparkConf, SparkFunSuite}
@@ -188,6 +193,67 @@ class FileAppenderSuite extends SparkFunSuite with BeforeAndAfter with Logging {
     testAppenderSelection[FileAppender, Any](rollingStrategy("xyz"))
   }
 
+  test("file appender async close stream abruptly") {
+    // Test FileAppender reaction to closing InputStream using a mock logging appender
+    val mockAppender = mock(classOf[Appender])
+    val loggingEventCaptor = new ArgumentCaptor[LoggingEvent]
+
+    // Make sure only logging errors
+    val logger = Logger.getRootLogger
+    logger.setLevel(Level.ERROR)
+    logger.addAppender(mockAppender)
+
+    val testOutputStream = new PipedOutputStream()
+    val testInputStream = new PipedInputStream(testOutputStream)
+
+    // Close the stream before appender tries to read will cause an IOException
+    testInputStream.close()
+    testOutputStream.close()
+    val appender = FileAppender(testInputStream, testFile, new SparkConf)
+
+    appender.awaitTermination()
+
+    // If InputStream was closed without first stopping the appender, an exception will be logged
+    verify(mockAppender, atLeast(1)).doAppend(loggingEventCaptor.capture)
+    val loggingEvent = loggingEventCaptor.getValue
+    assert(loggingEvent.getThrowableInformation !== null)
+    assert(loggingEvent.getThrowableInformation.getThrowable.isInstanceOf[IOException])
+  }
+
+  test("file appender async close stream gracefully") {
+    // Test FileAppender reaction to closing InputStream using a mock logging appender
+    val mockAppender = mock(classOf[Appender])
+    val loggingEventCaptor = new ArgumentCaptor[LoggingEvent]
+
+    // Make sure only logging errors
+    val logger = Logger.getRootLogger
+    logger.setLevel(Level.ERROR)
+    logger.addAppender(mockAppender)
+
+    val testOutputStream = new PipedOutputStream()
+    val testInputStream = new PipedInputStream(testOutputStream) with LatchedInputStream
+
+    // Close the stream before appender tries to read will cause an IOException
+    testInputStream.close()
+    testOutputStream.close()
+    val appender = FileAppender(testInputStream, testFile, new SparkConf)
+
+    // Stop the appender before an IOException is called during read
+    testInputStream.latchReadStarted.await()
+    appender.stop()
+    testInputStream.latchReadProceed.countDown()
+
+    appender.awaitTermination()
+
+    // Make sure no IOException errors have been logged as a result of appender closing gracefully
+    verify(mockAppender, atLeast(0)).doAppend(loggingEventCaptor.capture)
+    import scala.collection.JavaConverters._
+    loggingEventCaptor.getAllValues.asScala.foreach { loggingEvent =>
+      assert(loggingEvent.getThrowableInformation === null
+        || !loggingEvent.getThrowableInformation.getThrowable.isInstanceOf[IOException])
+    }
+  }
+
   /**
    * Run the rolling file appender with data and see whether all the data was written correctly
    * across rolled over files.
@@ -228,4 +294,15 @@ class FileAppenderSuite extends SparkFunSuite with BeforeAndAfter with Logging {
       file.getName.startsWith(testFile.getName)
     }.foreach { _.delete() }
   }
+
+  /** Used to synchronize when read is called on a stream */
+  private trait LatchedInputStream extends PipedInputStream {
+    val latchReadStarted = new CountDownLatch(1)
+    val latchReadProceed = new CountDownLatch(1)
+    abstract override def read(): Int = {
+      latchReadStarted.countDown()
+      latchReadProceed.await()
+      super.read()
+    }
+  }
 }