spark2.0源码阅读 剖析spark-shell

• spark-shell脚本
• spark-submit脚本
• spark-class脚本
• 总结

function main() {
  if $cygwin; then
    # Workaround for issue involving JLine and Cygwin
    # (see http://sourceforge.net/p/jline/bugs/40/).
    # If you're using the Mintty terminal emulator in Cygwin, may need to set the
    # "Backspace sends ^H" setting in "Keys" section of the Mintty options
    # (see https://github.com/sbt/sbt/issues/562).
    stty -icanon min 1 -echo > /dev/null 2>&1
    export SPARK_SUBMIT_OPTS="$SPARK_SUBMIT_OPTS -Djline.terminal=unix"
    "${SPARK_HOME}"/bin/spark-submit --class org.apache.spark.repl.Main --name "Spark shell" "$@"
    stty icanon echo > /dev/null 2>&1
  else
    export SPARK_SUBMIT_OPTS
    "${SPARK_HOME}"/bin/spark-submit --class org.apache.spark.repl.Main --name "Spark shell" "$@"
  fi
}

我们看到脚本了执行了/bin/spark-submit脚本
/usr/local/spark/bin/spark-submit --class org.apache.spark.repl.Main --name Spark shell

if [ -z "${SPARK_HOME}" ]; then
  source "$(dirname "$0")"/find-spark-home
fi

# disable randomized hash for string in Python 3.3+
export PYTHONHASHSEED=0

exec "${SPARK_HOME}"/bin/spark-class org.apache.spark.deploy.SparkSubmit "$@"

这里其实执行了/bin/spark-class脚本
/usr/local/spark/bin/spark-class org.apache.spark.deploy.SparkSubmit --class org.apache.spark.repl.Main --name Spark shel

# Find the java binary
if [ -n "${JAVA_HOME}" ]; then
  RUNNER="${JAVA_HOME}/bin/java"
else
  if [ "$(command -v java)" ]; then
    RUNNER="java"
  else
    echo "JAVA_HOME is not set" >&2
    exit 1
  fi
fi
。。。
build_command() {
  "$RUNNER" -Xmx128m -cp "$LAUNCH_CLASSPATH" org.apache.spark.launcher.Main "$@"
  printf "%d" $?
}
。。。
exec "${CMD[@]}"

实际执行命令
/usr/local/java/bin/java -cp /usr/local/spark/conf/:/usr/local/spark/jars/ -Dscala.usejavacp=true -Xmx1g org.apache.spark.deploy.SparkSubmit --class org.apache.spark.repl.Main --name Spark shell spark-shell /usr/local/java/bin/java -Xmx128m -cp /usr/local/spark/jars/ org.apache.spark.launcher.Main org.apache.spark.deploy.SparkSubmit --class org.apache.spark.repl.Main --name Spark shell**

`

可以看到其实在拼接java命令启动以SparkSubmit为主类的应用程序