[SPARK-4924] Add a library for launching Spark jobs programmatically.

This change encapsulates all the logic involved in launching a Spark job
into a small Java library that can be easily embedded into other applications.

The overall goal of this change is twofold, as described in the bug:

- Provide a public API for launching Spark processes. This is a common request
  from users and currently there's no good answer for it.

- Remove a lot of the duplicated code and other coupling that exists in the
  different parts of Spark that deal with launching processes.

A lot of the duplication was due to different code needed to build an
application's classpath (and the bootstrapper needed to run the driver in
certain situations), and also different code needed to parse spark-submit
command line options in different contexts. The change centralizes those
as much as possible so that all code paths can rely on the library for
handling those appropriately.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #3916 from vanzin/SPARK-4924 and squashes the following commits:

18c7e4d [Marcelo Vanzin] Fix make-distribution.sh.
2ce741f [Marcelo Vanzin] Add lots of quotes.
3b28a75 [Marcelo Vanzin] Update new pom.
a1b8af1 [Marcelo Vanzin] Merge branch 'master' into SPARK-4924
897141f [Marcelo Vanzin] Review feedback.
e2367d2 [Marcelo Vanzin] Merge branch 'master' into SPARK-4924
28cd35e [Marcelo Vanzin] Remove stale comment.
b1d86b0 [Marcelo Vanzin] Merge branch 'master' into SPARK-4924
00505f9 [Marcelo Vanzin] Add blurb about new API in the programming guide.
5f4ddcc [Marcelo Vanzin] Better usage messages.
92a9cfb [Marcelo Vanzin] Fix Win32 launcher, usage.
6184c07 [Marcelo Vanzin] Rename field.
4c19196 [Marcelo Vanzin] Update comment.
7e66c18 [Marcelo Vanzin] Fix pyspark tests.
0031a8e [Marcelo Vanzin] Review feedback.
c12d84b [Marcelo Vanzin] Review feedback. And fix spark-submit on Windows.
e2d4d71 [Marcelo Vanzin] Simplify some code used to launch pyspark.
43008a7 [Marcelo Vanzin] Don't make builder extend SparkLauncher.
b4d6912 [Marcelo Vanzin] Use spark-submit script in SparkLauncher.
28b1434 [Marcelo Vanzin] Add a comment.
304333a [Marcelo Vanzin] Fix propagation of properties file arg.
bb67b93 [Marcelo Vanzin] Remove unrelated Yarn change (that is also wrong).
8ec0243 [Marcelo Vanzin] Add missing newline.
95ddfa8 [Marcelo Vanzin] Fix handling of --help for spark-class command builder.
72da7ec [Marcelo Vanzin] Rename SparkClassLauncher.
62978e4 [Marcelo Vanzin] Minor cleanup of Windows code path.
9cd5b44 [Marcelo Vanzin] Make all non-public APIs package-private.
e4c80b6 [Marcelo Vanzin] Reorganize the code so that only SparkLauncher is public.
e50dc5e [Marcelo Vanzin] Merge branch 'master' into SPARK-4924
de81da2 [Marcelo Vanzin] Fix CommandUtils.
86a87bf [Marcelo Vanzin] Merge branch 'master' into SPARK-4924
2061967 [Marcelo Vanzin] Merge branch 'master' into SPARK-4924
46d46da [Marcelo Vanzin] Clean up a test and make it more future-proof.
b93692a [Marcelo Vanzin] Merge branch 'master' into SPARK-4924
ad03c48 [Marcelo Vanzin] Revert "Fix a thread-safety issue in "local" mode."
0b509d0 [Marcelo Vanzin] Merge branch 'master' into SPARK-4924
23aa2a9 [Marcelo Vanzin] Read java-opts from conf dir, not spark home.
7cff919 [Marcelo Vanzin] Javadoc updates.
eae4d8e [Marcelo Vanzin] Fix new unit tests on Windows.
e570fb5 [Marcelo Vanzin] Merge branch 'master' into SPARK-4924
44cd5f7 [Marcelo Vanzin] Add package-info.java, clean up javadocs.
f7cacff [Marcelo Vanzin] Remove "launch Spark in new thread" feature.
7ed8859 [Marcelo Vanzin] Some more feedback.
54cd4fd [Marcelo Vanzin] Merge branch 'master' into SPARK-4924
61919df [Marcelo Vanzin] Clean leftover debug statement.
aae5897 [Marcelo Vanzin] Use launcher classes instead of jars in non-release mode.
e584fc3 [Marcelo Vanzin] Rework command building a little bit.
525ef5b [Marcelo Vanzin] Rework Unix spark-class to handle argument with newlines.
8ac4e92 [Marcelo Vanzin] Minor test cleanup.
e946a99 [Marcelo Vanzin] Merge PySparkLauncher into SparkSubmitCliLauncher.
c617539 [Marcelo Vanzin] Review feedback round 1.
fc6a3e2 [Marcelo Vanzin] Merge branch 'master' into SPARK-4924
f26556b [Marcelo Vanzin] Fix a thread-safety issue in "local" mode.
2f4e8b4 [Marcelo Vanzin] Changes needed to make this work with SPARK-4048.
799fc20 [Marcelo Vanzin] Merge branch 'master' into SPARK-4924
bb5d324 [Marcelo Vanzin] Merge branch 'master' into SPARK-4924
53faef1 [Marcelo Vanzin] Merge branch 'master' into SPARK-4924
a7936ef [Marcelo Vanzin] Fix pyspark tests.
656374e [Marcelo Vanzin] Mima fixes.
4d511e7 [Marcelo Vanzin] Fix tools search code.
7a01e4a [Marcelo Vanzin] Fix pyspark on Yarn.
1b3f6e9 [Marcelo Vanzin] Call SparkSubmit from spark-class launcher for unknown classes.
25c5ae6 [Marcelo Vanzin] Centralize SparkSubmit command line parsing.
27be98a [Marcelo Vanzin] Modify Spark to use launcher lib.
6f70eea [Marcelo Vanzin] [SPARK-4924] Add a library for launching Spark jobs programatically.

1 files changed, 30 insertions, 111 deletions

diff --git a/bin/spark-class2.cmd b/bin/spark-class2.cmd
index da46543647..37d22215a0 100644
--- a/bin/spark-class2.cmd
+++ b/bin/spark-class2.cmd
@@ -17,135 +17,54 @@ rem See the License for the specific language governing permissions and
 rem limitations under the License.
 rem
 
-rem Any changes to this file must be reflected in SparkSubmitDriverBootstrapper.scala!
-
-setlocal enabledelayedexpansion
-
-set SCALA_VERSION=2.10
-
 rem Figure out where the Spark framework is installed
-set FWDIR=%~dp0..\
-
-rem Export this as SPARK_HOME
-set SPARK_HOME=%FWDIR%
+set SPARK_HOME=%~dp0..
 
 rem Load environment variables from conf\spark-env.cmd, if it exists
-if exist "%FWDIR%conf\spark-env.cmd" call "%FWDIR%conf\spark-env.cmd"
+if exist "%SPARK_HOME%\conf\spark-env.cmd" call "%SPARK_HOME%\conf\spark-env.cmd"
 
 rem Test that an argument was given
-if not "x%1"=="x" goto arg_given
+if "x%1"=="x" (
   echo Usage: spark-class ^<class^> [^<args^>]
-  goto exit
-:arg_given
-
-if not "x%SPARK_MEM%"=="x" (
-  echo Warning: SPARK_MEM is deprecated, please use a more specific config option
-  echo e.g., spark.executor.memory or spark.driver.memory.
+  exit /b 1
 )
 
-rem Use SPARK_MEM or 512m as the default memory, to be overridden by specific options
-set OUR_JAVA_MEM=%SPARK_MEM%
-if "x%OUR_JAVA_MEM%"=="x" set OUR_JAVA_MEM=512m
-
-set SPARK_DAEMON_JAVA_OPTS=%SPARK_DAEMON_JAVA_OPTS% -Dspark.akka.logLifecycleEvents=true
-
-rem Add java opts and memory settings for master, worker, history server, executors, and repl.
-rem Master, Worker and HistoryServer use SPARK_DAEMON_JAVA_OPTS (and specific opts) + SPARK_DAEMON_MEMORY.
-if "%1"=="org.apache.spark.deploy.master.Master" (
-  set OUR_JAVA_OPTS=%SPARK_DAEMON_JAVA_OPTS% %SPARK_MASTER_OPTS%
-  if not "x%SPARK_DAEMON_MEMORY%"=="x" set OUR_JAVA_MEM=%SPARK_DAEMON_MEMORY%
-) else if "%1"=="org.apache.spark.deploy.worker.Worker" (
-  set OUR_JAVA_OPTS=%SPARK_DAEMON_JAVA_OPTS% %SPARK_WORKER_OPTS%
-  if not "x%SPARK_DAEMON_MEMORY%"=="x" set OUR_JAVA_MEM=%SPARK_DAEMON_MEMORY%
-) else if "%1"=="org.apache.spark.deploy.history.HistoryServer" (
-  set OUR_JAVA_OPTS=%SPARK_DAEMON_JAVA_OPTS% %SPARK_HISTORY_OPTS%
-  if not "x%SPARK_DAEMON_MEMORY%"=="x" set OUR_JAVA_MEM=%SPARK_DAEMON_MEMORY%
-
-rem Executors use SPARK_JAVA_OPTS + SPARK_EXECUTOR_MEMORY.
-) else if "%1"=="org.apache.spark.executor.CoarseGrainedExecutorBackend" (
-  set OUR_JAVA_OPTS=%SPARK_JAVA_OPTS% %SPARK_EXECUTOR_OPTS%
-  if not "x%SPARK_EXECUTOR_MEMORY%"=="x" set OUR_JAVA_MEM=%SPARK_EXECUTOR_MEMORY%
-) else if "%1"=="org.apache.spark.executor.MesosExecutorBackend" (
-  set OUR_JAVA_OPTS=%SPARK_JAVA_OPTS% %SPARK_EXECUTOR_OPTS%
-  if not "x%SPARK_EXECUTOR_MEMORY%"=="x" set OUR_JAVA_MEM=%SPARK_EXECUTOR_MEMORY%
+set LAUNCHER_CP=0
+if exist %SPARK_HOME%\RELEASE goto find_release_launcher
 
-rem Spark submit uses SPARK_JAVA_OPTS + SPARK_SUBMIT_OPTS +
-rem SPARK_DRIVER_MEMORY + SPARK_SUBMIT_DRIVER_MEMORY.
-rem The repl also uses SPARK_REPL_OPTS.
-) else if "%1"=="org.apache.spark.deploy.SparkSubmit" (
-  set OUR_JAVA_OPTS=%SPARK_JAVA_OPTS% %SPARK_SUBMIT_OPTS% %SPARK_REPL_OPTS%
-  if not "x%SPARK_SUBMIT_LIBRARY_PATH%"=="x" (
-    set OUR_JAVA_OPTS=!OUR_JAVA_OPTS! -Djava.library.path=%SPARK_SUBMIT_LIBRARY_PATH%
-  ) else if not "x%SPARK_LIBRARY_PATH%"=="x" (
-    set OUR_JAVA_OPTS=!OUR_JAVA_OPTS! -Djava.library.path=%SPARK_LIBRARY_PATH%
-  )
-  if not "x%SPARK_DRIVER_MEMORY%"=="x" set OUR_JAVA_MEM=%SPARK_DRIVER_MEMORY%
-  if not "x%SPARK_SUBMIT_DRIVER_MEMORY%"=="x" set OUR_JAVA_MEM=%SPARK_SUBMIT_DRIVER_MEMORY%
-) else (
-  set OUR_JAVA_OPTS=%SPARK_JAVA_OPTS%
-  if not "x%SPARK_DRIVER_MEMORY%"=="x" set OUR_JAVA_MEM=%SPARK_DRIVER_MEMORY%
+rem Look for the Spark launcher in both Scala build directories. The launcher doesn't use Scala so
+rem it doesn't really matter which one is picked up. Add the compiled classes directly to the
+rem classpath instead of looking for a jar file, since it's very common for people using sbt to use
+rem the "assembly" target instead of "package".
+set LAUNCHER_CLASSES=%SPARK_HOME%\launcher\target\scala-2.10\classes
+if exist %LAUNCHER_CLASSES% (
+  set LAUNCHER_CP=%LAUNCHER_CLASSES%
 )
-
-rem Set JAVA_OPTS to be able to load native libraries and to set heap size
-for /f "tokens=3" %%i in ('java -version 2^>^&1 ^| find "version"') do set jversion=%%i
-for /f "tokens=1 delims=_" %%i in ("%jversion:~1,-1%") do set jversion=%%i
-if "%jversion%" geq "1.8.0" (
-  set JAVA_OPTS=%OUR_JAVA_OPTS% -Xms%OUR_JAVA_MEM% -Xmx%OUR_JAVA_MEM%
-) else (
-  set JAVA_OPTS=-XX:MaxPermSize=128m %OUR_JAVA_OPTS% -Xms%OUR_JAVA_MEM% -Xmx%OUR_JAVA_MEM%
+set LAUNCHER_CLASSES=%SPARK_HOME%\launcher\target\scala-2.11\classes
+if exist %LAUNCHER_CLASSES% (
+  set LAUNCHER_CP=%LAUNCHER_CLASSES%
 )
-rem Attention: when changing the way the JAVA_OPTS are assembled, the change must be reflected in CommandUtils.scala!
+goto check_launcher
 
-rem Test whether the user has built Spark
-if exist "%FWDIR%RELEASE" goto skip_build_test
-set FOUND_JAR=0
-for %%d in ("%FWDIR%assembly\target\scala-%SCALA_VERSION%\spark-assembly*hadoop*.jar") do (
-  set FOUND_JAR=1
-)
-if "%FOUND_JAR%"=="0" (
-  echo Failed to find Spark assembly JAR.
-  echo You need to build Spark before running this program.
-  goto exit
+:find_release_launcher
+for %%d in (%SPARK_HOME%\lib\spark-launcher*.jar) do (
+  set LAUNCHER_CP=%%d
 )
-:skip_build_test
 
-set TOOLS_DIR=%FWDIR%tools
-set SPARK_TOOLS_JAR=
-for %%d in ("%TOOLS_DIR%\target\scala-%SCALA_VERSION%\spark-tools*assembly*.jar") do (
-  set SPARK_TOOLS_JAR=%%d
+:check_launcher
+if "%LAUNCHER_CP%"=="0" (
+  echo Failed to find Spark launcher JAR.
+  echo You need to build Spark before running this program.
+  exit /b 1
 )
 
-rem Compute classpath using external script
-set DONT_PRINT_CLASSPATH=1
-call "%FWDIR%bin\compute-classpath.cmd"
-set DONT_PRINT_CLASSPATH=0
-set CLASSPATH=%CLASSPATH%;%SPARK_TOOLS_JAR%
-
 rem Figure out where java is.
 set RUNNER=java
 if not "x%JAVA_HOME%"=="x" set RUNNER=%JAVA_HOME%\bin\java
 
-rem In Spark submit client mode, the driver is launched in the same JVM as Spark submit itself.
-rem Here we must parse the properties file for relevant "spark.driver.*" configs before launching
-rem the driver JVM itself. Instead of handling this complexity here, we launch a separate JVM
-rem to prepare the launch environment of this driver JVM.
-
-rem In this case, leave out the main class (org.apache.spark.deploy.SparkSubmit) and use our own.
-rem Leaving out the first argument is surprisingly difficult to do in Windows. Note that this must
-rem be done here because the Windows "shift" command does not work in a conditional block.
-set BOOTSTRAP_ARGS=
-shift
-:start_parse
-if "%~1" == "" goto end_parse
-set BOOTSTRAP_ARGS=%BOOTSTRAP_ARGS% %~1
-shift
-goto start_parse
-:end_parse
-
-if not [%SPARK_SUBMIT_BOOTSTRAP_DRIVER%] == [] (
-  set SPARK_CLASS=1
-  "%RUNNER%" org.apache.spark.deploy.SparkSubmitDriverBootstrapper %BOOTSTRAP_ARGS%
-) else (
-  "%RUNNER%" -cp "%CLASSPATH%" %JAVA_OPTS% %*
+rem The launcher library prints the command to be executed in a single line suitable for being
+rem executed by the batch interpreter. So read all the output of the launcher into a variable.
+for /f "tokens=*" %%i in ('cmd /C ""%RUNNER%" -cp %LAUNCHER_CP% org.apache.spark.launcher.Main %*"') do (
+  set SPARK_CMD=%%i
 )
-:exit
+%SPARK_CMD%