Resolve Forever Waiting Issue in FlintJob for Streaming Jobs (#156)

This commit specifically tackles the issue detailed in #116. Previously, regardless of whether a streaming job was successfully initiated or encountered syntax/semantic errors during creation, the main thread would indefinitely wait for the streaming job's termination. This behavior often led to situations where the main thread would hang indefinitely, waiting for a streaming job that had not even started due to errors.

This update introduces a change: spark.streams.awaitAnyTermination() is now invoked only if the streaming query is executed without encountering any exceptions.

Testing Performed:
* Replicated the original issue to confirm its presence.
* Applied the fix and verified that the issue of indefinite waiting has been successfully resolved.

Signed-off-by: Kaituo Li <[email protected]>

spark-sql-application/src/main/scala/org/apache/spark/sql/FlintJob.scala

@@ -58,6 +58,7 @@ object FlintJob extends Logging with FlintJobExecutor {
     // osClient needs spark session to be created first to get FlintOptions initialized.
     // Otherwise, we will have connection exception from EMR-S to OS.
     val osClient = new OSClient(FlintSparkConf().flintOptions())
+    var exceptionThrown = true
     try {
       val futureMappingCheck = Future {
         checkAndCreateIndex(osClient, resultIndex)
@@ -70,6 +71,7 @@ object FlintJob extends Logging with FlintJobExecutor {
         case Left(error) =>
           getFailedData(spark, dataSource, error, "", query, "", startTime, currentTimeProvider)
       })
+      exceptionThrown = false
     } catch {
       case e: TimeoutException =>
         val error = s"Getting the mapping of index $resultIndex timed out"
@@ -82,8 +84,9 @@ object FlintJob extends Logging with FlintJobExecutor {
           getFailedData(spark, dataSource, error, "", query, "", startTime, currentTimeProvider))
     } finally {
       dataToWrite.foreach(df => writeDataFrameToOpensearch(df, resultIndex, osClient))
-      // Stop SparkSession if it is not streaming job
-      if (wait.equalsIgnoreCase("streaming")) {
+      // Stop SparkSession if streaming job succeeds
+      if (!exceptionThrown && wait.equalsIgnoreCase("streaming")) {
+        // wait if any child thread to finish before the main thread terminates
         spark.streams.awaitAnyTermination()
       } else {
         spark.stop()