Github user choochootrain commented on a diff in the pull request:
https://github.com/apache/spark/pull/9367#discussion_r43942556
--- Diff:
core/src/test/scala/org/apache/spark/deploy/SparkSubmitSuite.scala ---
@@ -366,6 +367,72 @@ class SparkSubmitSuite
}
}
+ // SPARK-11195
+ test("classes are correctly loaded when tasks fail") {
+ // Compile a simple jar that throws a user defined exception on the
driver
+ val tempDir = Utils.createTempDir()
+ val srcDir = new File(tempDir, "repro/")
+ srcDir.mkdirs()
+ // scalastyle:off line.size.limit
+ val mainSource = new JavaSourceFromString(new File(srcDir,
"MyJob").getAbsolutePath,
+ """package repro;
+ |
+ |import java.util.*;
+ |import java.util.regex.*;
+ |import org.apache.spark.*;
+ |import org.apache.spark.api.java.*;
+ |import org.apache.spark.api.java.function.*;
+ |
+ |public class MyJob {
+ | public static class MyException extends Exception {
+ | }
+ |
+ | public static void main(String[] args) {
+ | SparkConf conf = new SparkConf();
+ | JavaSparkContext sc = new JavaSparkContext(conf);
+ |
+ | JavaRDD rdd = sc.parallelize(Arrays.asList(new Integer[]{1}),
1).map(new Function<Integer, Boolean>() {
+ | public Boolean call(Integer x) throws MyException {
+ | throw new MyException();
+ | }
+ | });
+ |
+ | try {
+ | rdd.collect();
+ |
+ | assert(false); // should be unreachable
+ | } catch (Exception e) {
+ | // the driver should not have any problems resolving the
exception class and determining
+ | // why the task failed.
+ |
+ | Pattern unknownFailure = Pattern.compile(".*Lost task.*:
UnknownReason.*", Pattern.DOTALL);
+ | Pattern expectedFailure = Pattern.compile(".*Lost task.*:
repro.MyJob\\$MyException.*", Pattern.DOTALL);
+ |
+ | assert(!unknownFailure.matcher(e.getMessage()).matches());
+ | assert(expectedFailure.matcher(e.getMessage()).matches());
+ | }
+ | }
+ |}
+ """.stripMargin)
+ // scalastyle:on line.size.limit
+ val sparkJar =
"../assembly/target/scala-2.10/spark-assembly-1.5.1-hadoop2.2.0.jar"
--- End diff --
all this patch does is make `TaskResult` deserialization use
`Utils.getContextOrSparkClassLoader` (the classloader which loaded the
`spark-submit`ed jar) instead of `Utils.getSparkClassLoader` (this is
`AppClassLoader` which only has spark classes in it). without this patch, a
failed task would not be able to deserialize an exception if it did not exist
in `Utils.getSparkClassLoader`.
in order to reproduce this issue, i set up a situation where
`Utils.getContextOnSparkClassLoader` contains `MyException` but
`Utils.getSparkClassLoader` does not (see
https://issues.apache.org/jira/browse/SPARK-11195). this is easy to manually
test with `spark-submit` and a user defined exception, but turning this into an
automated test is proving to be much trickier. here are the 3 options:
* :x: if i place all of the code into `SparkSubmitSuite`, the bug won't be
hit because `MyException` will be in the root classloader and my patch makes no
difference.
* :grey_question: if i place all of the code into an external jar and run
`spark-submit`, i can set up the same situation as my repro which found this
bug. the issue i am running into is that i need a spark classpath in order to
compile my jar. i can use the assembled jar, but this changes depending on the
maven profiles that are enabled and so on.
* :grey_question: i can try @brkyvz & @yhuai's hybrid approach of putting
only the exception into a jar and the rest of the code into `SparkSubmitSuite`.
i will have to do the following in order to repro this issue:
* load the jar with `MyException` in a new classloader whose parent is
the root classloader
* somehow allow this classloader to be used by the driver and the
executor *without* changing `Utils.getSparkClassLoader`.
at this point am i not reimplementing `spark-submit`? :)
the final approach is certainly worth trying, i'll take a look at it later
today.
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