[SPARK-6324] [CORE] Centralize handling of script usage messages.

Reorganize code so that the launcher library handles most of the work
of printing usage messages, instead of having an awkward protocol between
the library and the scripts for that.

This mostly applies to SparkSubmit, since the launcher lib does not do
command line parsing for classes invoked in other ways, and thus cannot
handle failures for those. Most scripts end up going through SparkSubmit,
though, so it all works.

The change adds a new, internal command line switch, "--usage-error",
which prints the usage message and exits with a non-zero status. Scripts
can override the command printed in the usage message by setting an
environment variable - this avoids having to grep the output of
SparkSubmit to remove references to the "spark-submit" script.

The only sub-optimal part of the change is the special handling for the
spark-sql usage, which is now done in SparkSubmitArguments.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #5841 from vanzin/SPARK-6324 and squashes the following commits:

2821481 [Marcelo Vanzin] Merge branch 'master' into SPARK-6324
bf139b5 [Marcelo Vanzin] Filter output of Spark SQL CLI help.
c6609bf [Marcelo Vanzin] Fix exit code never being used when printing usage messages.
6bc1b41 [Marcelo Vanzin] [SPARK-6324] [core] Centralize handling of script usage messages.

1 files changed, 2 insertions, 37 deletions

diff --git a/bin/spark-sql b/bin/spark-sql
index ca1729f4cf..4ea7bc6e39 100755
--- a/bin/spark-sql
+++ b/bin/spark-sql
@@ -17,41 +17,6 @@
 # limitations under the License.
 #
 
-#
-# Shell script for starting the Spark SQL CLI
-
-# Enter posix mode for bash
-set -o posix
-
-# NOTE: This exact class name is matched downstream by SparkSubmit.
-# Any changes need to be reflected there.
-export CLASS="org.apache.spark.sql.hive.thriftserver.SparkSQLCLIDriver"
-
-# Figure out where Spark is installed
 export FWDIR="$(cd "`dirname "$0"`"/..; pwd)"
-
-function usage {
-  if [ -n "$1" ]; then
-    echo "$1"
-  fi
-  echo "Usage: ./bin/spark-sql [options] [cli option]"
-  pattern="usage"
-  pattern+="\|Spark assembly has been built with Hive"
-  pattern+="\|NOTE: SPARK_PREPEND_CLASSES is set"
-  pattern+="\|Spark Command: "
-  pattern+="\|--help"
-  pattern+="\|======="
-
-  "$FWDIR"/bin/spark-submit --help 2>&1 | grep -v Usage 1>&2
-  echo
-  echo "CLI options:"
-  "$FWDIR"/bin/spark-class "$CLASS" --help 2>&1 | grep -v "$pattern" 1>&2
-  exit "$2"
-}
-export -f usage
-
-if [[ "$@" = *--help ]] || [[ "$@" = *-h ]]; then
-  usage "" 0
-fi
-
-exec "$FWDIR"/bin/spark-submit --class "$CLASS" "$@"
+export _SPARK_CMD_USAGE="Usage: ./bin/spark-sql [options] [cli option]"
+exec "$FWDIR"/bin/spark-submit --class org.apache.spark.sql.hive.thriftserver.SparkSQLCLIDriver "$@"