Spark-Core之spark-shell脚本分析

Spark的bin目录下，spark-shell脚本是工业级脚本，其它脚本也是类似的，写的都非常好。生产上，很多作业都是通过脚本来进行启动的，如果以后用到的话，可以参考这些工业级的脚本，很多可以学习参考的地方，可以直接拿过来使用，学会“抄”。

spark-shell脚本：

[hadoop@hadoop001 bin]$ cat spark-shell 
#!/usr/bin/env bash

#
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License.  You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

#
# Shell script for starting the Spark Shell REPL

cygwin=false
case "$(uname)" in
  CYGWIN*) cygwin=true;;
esac

# Enter posix mode for bash
set -o posix

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

export _SPARK_CMD_USAGE="Usage: ./bin/spark-shell [options]

Scala REPL options:
  -I <file>                   preload <file>, enforcing line-by-line interpretation"

# SPARK-4161: scala does not assume use of the java classpath,
# so we need to add the "-Dscala.usejavacp=true" flag manually. We
# do this specifically for the Spark shell because the scala REPL
# has its own class loader, and any additional classpath specified
# through spark.driver.extraClassPath is not automatically propagated.
SPARK_SUBMIT_OPTS="$SPARK_SUBMIT_OPTS -Dscala.usejavacp=true"

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
}

# Copy restore-TTY-on-exit functions from Scala script so spark-shell exits properly even in
# binary distribution of Spark where Scala is not installed
exit_status=127
saved_stty=""

# restore stty settings (echo in particular)
function restoreSttySettings() {
  stty $saved_stty
  saved_stty=""
}

function onExit() {
  if [[ "$saved_stty" != "" ]]; then
    restoreSttySettings
  fi
  exit $exit_status
}

# to reenable echo if we are interrupted before completing.
trap onExit INT

# save terminal settings
saved_stty=$(stty -g 2>/dev/null)
# clear on error so we don't later try to restore them
if [[ ! $? ]]; then
  saved_stty=""
fi

main "$@"

# record the exit status lest it be overwritten:
# then reenable echo and propagate the code.
exit_status=$?
onExit

spark-submit脚本：

[hadoop@hadoop001 bin]$ cat spark-submit 
#!/usr/bin/env bash

#
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License.  You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

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

先判断是不是Linux系统
判断SPARK_HOME有没有配置，如果没有配置就调用当前目录下的find-spark-home脚本去找SPARK_HOME
然后调用main 函数
然后main函数里直接转到else
else里面调用的是spark-submit，调用class org.apache.spark.repl.Main这个类，把name设置成了Spark shell，后面跟的是其它所有参数。
…
调用spark-submit时候，spark-submit脚本里先判断SPARK_HOME是否存在，
调用"${SPARK_HOME}"/bin/spark-class，下面的 org.apache.spark.deploy.SparkSubmit这个类，后面跟上所有参数。
…
具体不再描述。

其它像Hadoop之类的下面bin下面的很多启动脚本都是类似。