flink版本: flink-1.12.1

源码位置:  flink-dist/src/main/flink-bin/bin/flink

flink命令源码:

#!/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.
################################################################################target="$0"
# For the case, the executable has been directly symlinked, figure out
# the correct bin path by following its symlink up to an upper bound.
# Note: we can't use the readlink utility here if we want to be POSIX
# compatible.
iteration=0
while [ -L "$target" ]; doif [ "$iteration" -gt 100 ]; thenecho "Cannot resolve path: You have a cyclic symlink in $target."breakfils=`ls -ld -- "$target"`target=`expr "$ls" : '.* -> \(.*\)$'`iteration=$((iteration + 1))
done# Convert relative path to absolute path
bin=`dirname "$target"`# get flink config
. "$bin"/config.shif [ "$FLINK_IDENT_STRING" = "" ]; thenFLINK_IDENT_STRING="$USER"
fiCC_CLASSPATH=`constructFlinkClassPath`log=$FLINK_LOG_DIR/flink-$FLINK_IDENT_STRING-client-$HOSTNAME.log
log_setting=(-Dlog.file="$log" -Dlog4j.configuration=file:"$FLINK_CONF_DIR"/log4j-cli.properties -Dlog4j.configurationFile=file:"$FLINK_CONF_DIR"/log4j-cli.properties -Dlogback.configurationFile=file:"$FLINK_CONF_DIR"/logback.xml)# Add Client-specific JVM options
FLINK_ENV_JAVA_OPTS="${FLINK_ENV_JAVA_OPTS} ${FLINK_ENV_JAVA_OPTS_CLI}"# Add HADOOP_CLASSPATH to allow the usage of Hadoop file systems
exec $JAVA_RUN $JVM_ARGS $FLINK_ENV_JAVA_OPTS "${log_setting[@]}" -classpath "`manglePathList "$CC_CLASSPATH:$INTERNAL_HADOOP_CLASSPATHS"`" org.apache.flink.client.cli.CliFrontend "$@"

首先讲第一段:

target="$0"
# For the case, the executable has been directly symlinked, figure out
# the correct bin path by following its symlink up to an upper bound.
# Note: we can't use the readlink utility here if we want to be POSIX
# compatible.# 注释内容翻译
# 对于可执行文件被建立符号链接的情况，按照其符号链接找出正确的bin路径， 符号链接次数有上限。
# 注意：如果我们想与POSIX兼容，就不能在这里使用readlink实用程序。iteration=0
while [ -L "$target" ]; doif [ "$iteration" -gt 100 ]; thenecho "Cannot resolve path: You have a cyclic symlink in $target."breakfils=`ls -ld -- "$target"`target=`expr "$ls" : '.* -> \(.*\)$'`iteration=$((iteration + 1))
done

工作中，很多人喜欢用符号链接(软连接)去将原始命令链接到一个新的文件。

例如: 

 ln  -s  /home/aaa    /opt/soft/flink-1.12.1/bin/flink

将 /home/aaa链接到/opt/soft/flink-1.12.1/bin/flink，  实际使用的时候就可以用 aaa去代替flink命令。 例如/opt/soft/flink-1.12.1/bin/flink run就可以用/home/aaa run代替。

以上代码主要是通过解析aaa命令的软链接信息获取到flink命令的原始为止。核心的是这两句

    ls=`ls -ld -- "$target"`target=`expr "$ls" : '.* -> \(.*\)$'`

通过ls -ld命令拿到当前"aaa"命令对应的软链接信息:软链接中最后一部分格式一般是

aaa -> /opt/soft/flink-1.12.1/bin/flink,

然后通过 expr命令解析这个字符串，获取到/opt/soft/flink-1.12.1/bin/flink这个字符串，然后获取到flink命令的位置，并赋值给target。

注意因为软链接可以链接多次，所以整个代码使用while循环包裹。

while [ -L "$target" ]

上面这句主要在判断当前的tatget是否是软连接，如果是才进入循环，寻找flink命令的位置；如果不是，说明target就是flink命令，则直接退出循环即可。

因为可以为软链接建立软链接，简单来说就是嵌套软链接，或者多次软链接。例如:

 ln  -s  /home/bbb    /home/aaaln  -s  /home/ccc    /home/bbb

代码iteration变量主要是针对以上情况，如果嵌套软链接的次数大于100次，循环终止执行。

# Convert relative path to absolute path
bin=`dirname "$target"`# get flink config
. "$bin"/config.shif [ "$FLINK_IDENT_STRING" = "" ]; thenFLINK_IDENT_STRING="$USER"
fiCC_CLASSPATH=`constructFlinkClassPath`log=$FLINK_LOG_DIR/flink-$FLINK_IDENT_STRING-client-$HOSTNAME.log
log_setting=(-Dlog.file="$log" -Dlog4j.configuration=file:"$FLINK_CONF_DIR"/log4j-cli.properties -Dlog4j.configurationFile=file:"$FLINK_CONF_DIR"/log4j-cli.properties -Dlogback.configurationFile=file:"$FLINK_CONF_DIR"/logback.xml)# Add Client-specific JVM options
FLINK_ENV_JAVA_OPTS="${FLINK_ENV_JAVA_OPTS} ${FLINK_ENV_JAVA_OPTS_CLI}"

找到真正的flink命令后，下面这段主要是解析，拼接各种配置变量。

注意这里很多变量，例如 FLINK_IDENT_STRING，在当前文件中都没有声明，上面又有一句

# get flink config
. "$bin"/config.sh

推测是在 config.sh中进行的。找到config.sh：

#!/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.
################################################################################constructFlinkClassPath() {local FLINK_DISTlocal FLINK_CLASSPATHwhile read -d '' -r jarfile ; doif [[ "$jarfile" =~ .*/flink-dist[^/]*.jar$ ]]; thenFLINK_DIST="$FLINK_DIST":"$jarfile"elif [[ "$FLINK_CLASSPATH" == "" ]]; thenFLINK_CLASSPATH="$jarfile";elseFLINK_CLASSPATH="$FLINK_CLASSPATH":"$jarfile"fidone < <(find "$FLINK_LIB_DIR" ! -type d -name '*.jar' -print0 | sort -z)if [[ "$FLINK_DIST" == "" ]]; then# write error message to stderr since stdout is stored as the classpath(>&2 echo "[ERROR] Flink distribution jar not found in $FLINK_LIB_DIR.")# exit function with empty classpath to force process failureexit 1fiecho "$FLINK_CLASSPATH""$FLINK_DIST"
}findFlinkDistJar() {local FLINK_DIST="`find "$FLINK_LIB_DIR" -name 'flink-dist*.jar'`"if [[ "$FLINK_DIST" == "" ]]; then# write error message to stderr since stdout is stored as the classpath(>&2 echo "[ERROR] Flink distribution jar not found in $FLINK_LIB_DIR.")# exit function with empty classpath to force process failureexit 1fiecho "$FLINK_DIST"
}# These are used to mangle paths that are passed to java when using
# cygwin. Cygwin paths are like linux paths, i.e. /path/to/somewhere
# but the windows java version expects them in Windows Format, i.e. C:\bla\blub.
# "cygpath" can do the conversion.
manglePath() {UNAME=$(uname -s)if [ "${UNAME:0:6}" == "CYGWIN" ]; thenecho `cygpath -w "$1"`elseecho $1fi
}manglePathList() {UNAME=$(uname -s)# a path list, for example a java classpathif [ "${UNAME:0:6}" == "CYGWIN" ]; thenecho `cygpath -wp "$1"`elseecho $1fi
}# Looks up a config value by key from a simple YAML-style key-value map.
# $1: key to look up
# $2: default value to return if key does not exist
# $3: config file to read from
readFromConfig() {local key=$1local defaultValue=$2local configFile=$3# first extract the value with the given key (1st sed), then trim the result (2nd sed)# if a key exists multiple times, take the "last" one (tail)local value=`sed -n "s/^[ ]*${key}[ ]*: \([^#]*\).*$/\1/p" "${configFile}" | sed "s/^ *//;s/ *$//" | tail -n 1`[ -z "$value" ] && echo "$defaultValue" || echo "$value"
}########################################################################################################################
# DEFAULT CONFIG VALUES: These values will be used when nothing has been specified in conf/flink-conf.yaml
# -or- the respective environment variables are not set.
######################################################################################################################### WARNING !!! , these values are only used if there is nothing else is specified in
# conf/flink-conf.yamlDEFAULT_ENV_PID_DIR="/tmp"                          # Directory to store *.pid files to
DEFAULT_ENV_LOG_MAX=10                              # Maximum number of old log files to keep
DEFAULT_ENV_JAVA_OPTS=""                            # Optional JVM args
DEFAULT_ENV_JAVA_OPTS_JM=""                         # Optional JVM args (JobManager)
DEFAULT_ENV_JAVA_OPTS_TM=""                         # Optional JVM args (TaskManager)
DEFAULT_ENV_JAVA_OPTS_HS=""                         # Optional JVM args (HistoryServer)
DEFAULT_ENV_JAVA_OPTS_CLI=""                        # Optional JVM args (Client)
DEFAULT_ENV_SSH_OPTS=""                             # Optional SSH parameters running in cluster mode
DEFAULT_YARN_CONF_DIR=""                            # YARN Configuration Directory, if necessary
DEFAULT_HADOOP_CONF_DIR=""                          # Hadoop Configuration Directory, if necessary
DEFAULT_HBASE_CONF_DIR=""                           # HBase Configuration Directory, if necessary########################################################################################################################
# CONFIG KEYS: The default values can be overwritten by the following keys in conf/flink-conf.yaml
########################################################################################################################KEY_TASKM_COMPUTE_NUMA="taskmanager.compute.numa"KEY_ENV_PID_DIR="env.pid.dir"
KEY_ENV_LOG_DIR="env.log.dir"
KEY_ENV_LOG_MAX="env.log.max"
KEY_ENV_YARN_CONF_DIR="env.yarn.conf.dir"
KEY_ENV_HADOOP_CONF_DIR="env.hadoop.conf.dir"
KEY_ENV_HBASE_CONF_DIR="env.hbase.conf.dir"
KEY_ENV_JAVA_HOME="env.java.home"
KEY_ENV_JAVA_OPTS="env.java.opts"
KEY_ENV_JAVA_OPTS_JM="env.java.opts.jobmanager"
KEY_ENV_JAVA_OPTS_TM="env.java.opts.taskmanager"
KEY_ENV_JAVA_OPTS_HS="env.java.opts.historyserver"
KEY_ENV_JAVA_OPTS_CLI="env.java.opts.client"
KEY_ENV_SSH_OPTS="env.ssh.opts"
KEY_HIGH_AVAILABILITY="high-availability"
KEY_ZK_HEAP_MB="zookeeper.heap.mb"########################################################################################################################
# PATHS AND CONFIG
########################################################################################################################target="$0"
# For the case, the executable has been directly symlinked, figure out
# the correct bin path by following its symlink up to an upper bound.
# Note: we can't use the readlink utility here if we want to be POSIX
# compatible.
iteration=0
while [ -L "$target" ]; doif [ "$iteration" -gt 100 ]; thenecho "Cannot resolve path: You have a cyclic symlink in $target."breakfils=`ls -ld -- "$target"`target=`expr "$ls" : '.* -> \(.*\)$'`iteration=$((iteration + 1))
done# Convert relative path to absolute path and resolve directory symlinks
bin=`dirname "$target"`
SYMLINK_RESOLVED_BIN=`cd "$bin"; pwd -P`# Define the main directory of the flink installation
# If config.sh is called by pyflink-shell.sh in python bin directory(pip installed), then do not need to set the FLINK_HOME here.
if [ -z "$_FLINK_HOME_DETERMINED" ]; thenFLINK_HOME=`dirname "$SYMLINK_RESOLVED_BIN"`
fi
FLINK_LIB_DIR=$FLINK_HOME/lib
FLINK_PLUGINS_DIR=$FLINK_HOME/plugins
FLINK_OPT_DIR=$FLINK_HOME/opt# These need to be mangled because they are directly passed to java.
# The above lib path is used by the shell script to retrieve jars in a
# directory, so it needs to be unmangled.
FLINK_HOME_DIR_MANGLED=`manglePath "$FLINK_HOME"`
if [ -z "$FLINK_CONF_DIR" ]; then FLINK_CONF_DIR=$FLINK_HOME_DIR_MANGLED/conf; fi
FLINK_BIN_DIR=$FLINK_HOME_DIR_MANGLED/bin
DEFAULT_FLINK_LOG_DIR=$FLINK_HOME_DIR_MANGLED/log
FLINK_CONF_FILE="flink-conf.yaml"
YAML_CONF=${FLINK_CONF_DIR}/${FLINK_CONF_FILE}### Exported environment variables ###
export FLINK_CONF_DIR
export FLINK_BIN_DIR
export FLINK_PLUGINS_DIR
# export /lib dir to access it during deployment of the Yarn staging files
export FLINK_LIB_DIR
# export /opt dir to access it for the SQL client
export FLINK_OPT_DIR########################################################################################################################
# ENVIRONMENT VARIABLES
######################################################################################################################### read JAVA_HOME from config with no default value
MY_JAVA_HOME=$(readFromConfig ${KEY_ENV_JAVA_HOME} "" "${YAML_CONF}")
# check if config specified JAVA_HOME
if [ -z "${MY_JAVA_HOME}" ]; then# config did not specify JAVA_HOME. Use system JAVA_HOMEMY_JAVA_HOME=${JAVA_HOME}
fi
# check if we have a valid JAVA_HOME and if java is not available
if [ -z "${MY_JAVA_HOME}" ] && ! type java > /dev/null 2> /dev/null; thenecho "Please specify JAVA_HOME. Either in Flink config ./conf/flink-conf.yaml or as system-wide JAVA_HOME."exit 1
elseJAVA_HOME=${MY_JAVA_HOME}
fiUNAME=$(uname -s)
if [ "${UNAME:0:6}" == "CYGWIN" ]; thenJAVA_RUN=java
elseif [[ -d $JAVA_HOME ]]; thenJAVA_RUN=$JAVA_HOME/bin/javaelseJAVA_RUN=javafi
fi# Define HOSTNAME if it is not already set
if [ -z "${HOSTNAME}" ]; thenHOSTNAME=`hostname`
fiIS_NUMBER="^[0-9]+$"# Verify that NUMA tooling is available
command -v numactl >/dev/null 2>&1
if [[ $? -ne 0 ]]; thenFLINK_TM_COMPUTE_NUMA="false"
else# Define FLINK_TM_COMPUTE_NUMA if it is not already setif [ -z "${FLINK_TM_COMPUTE_NUMA}" ]; thenFLINK_TM_COMPUTE_NUMA=$(readFromConfig ${KEY_TASKM_COMPUTE_NUMA} "false" "${YAML_CONF}")fi
fiif [ -z "${MAX_LOG_FILE_NUMBER}" ]; thenMAX_LOG_FILE_NUMBER=$(readFromConfig ${KEY_ENV_LOG_MAX} ${DEFAULT_ENV_LOG_MAX} "${YAML_CONF}")export MAX_LOG_FILE_NUMBER
fiif [ -z "${FLINK_LOG_DIR}" ]; thenFLINK_LOG_DIR=$(readFromConfig ${KEY_ENV_LOG_DIR} "${DEFAULT_FLINK_LOG_DIR}" "${YAML_CONF}")
fiif [ -z "${YARN_CONF_DIR}" ]; thenYARN_CONF_DIR=$(readFromConfig ${KEY_ENV_YARN_CONF_DIR} "${DEFAULT_YARN_CONF_DIR}" "${YAML_CONF}")
fiif [ -z "${HADOOP_CONF_DIR}" ]; thenHADOOP_CONF_DIR=$(readFromConfig ${KEY_ENV_HADOOP_CONF_DIR} "${DEFAULT_HADOOP_CONF_DIR}" "${YAML_CONF}")
fiif [ -z "${HBASE_CONF_DIR}" ]; thenHBASE_CONF_DIR=$(readFromConfig ${KEY_ENV_HBASE_CONF_DIR} "${DEFAULT_HBASE_CONF_DIR}" "${YAML_CONF}")
fiif [ -z "${FLINK_PID_DIR}" ]; thenFLINK_PID_DIR=$(readFromConfig ${KEY_ENV_PID_DIR} "${DEFAULT_ENV_PID_DIR}" "${YAML_CONF}")
fiif [ -z "${FLINK_ENV_JAVA_OPTS}" ]; thenFLINK_ENV_JAVA_OPTS=$(readFromConfig ${KEY_ENV_JAVA_OPTS} "${DEFAULT_ENV_JAVA_OPTS}" "${YAML_CONF}")# Remove leading and ending double quotes (if present) of valueFLINK_ENV_JAVA_OPTS="$( echo "${FLINK_ENV_JAVA_OPTS}" | sed -e 's/^"//'  -e 's/"$//' )"
fiif [ -z "${FLINK_ENV_JAVA_OPTS_JM}" ]; thenFLINK_ENV_JAVA_OPTS_JM=$(readFromConfig ${KEY_ENV_JAVA_OPTS_JM} "${DEFAULT_ENV_JAVA_OPTS_JM}" "${YAML_CONF}")# Remove leading and ending double quotes (if present) of valueFLINK_ENV_JAVA_OPTS_JM="$( echo "${FLINK_ENV_JAVA_OPTS_JM}" | sed -e 's/^"//'  -e 's/"$//' )"
fiif [ -z "${FLINK_ENV_JAVA_OPTS_TM}" ]; thenFLINK_ENV_JAVA_OPTS_TM=$(readFromConfig ${KEY_ENV_JAVA_OPTS_TM} "${DEFAULT_ENV_JAVA_OPTS_TM}" "${YAML_CONF}")# Remove leading and ending double quotes (if present) of valueFLINK_ENV_JAVA_OPTS_TM="$( echo "${FLINK_ENV_JAVA_OPTS_TM}" | sed -e 's/^"//'  -e 's/"$//' )"
fiif [ -z "${FLINK_ENV_JAVA_OPTS_HS}" ]; thenFLINK_ENV_JAVA_OPTS_HS=$(readFromConfig ${KEY_ENV_JAVA_OPTS_HS} "${DEFAULT_ENV_JAVA_OPTS_HS}" "${YAML_CONF}")# Remove leading and ending double quotes (if present) of valueFLINK_ENV_JAVA_OPTS_HS="$( echo "${FLINK_ENV_JAVA_OPTS_HS}" | sed -e 's/^"//'  -e 's/"$//' )"
fiif [ -z "${FLINK_ENV_JAVA_OPTS_CLI}" ]; thenFLINK_ENV_JAVA_OPTS_CLI=$(readFromConfig ${KEY_ENV_JAVA_OPTS_CLI} "${DEFAULT_ENV_JAVA_OPTS_CLI}" "${YAML_CONF}")# Remove leading and ending double quotes (if present) of valueFLINK_ENV_JAVA_OPTS_CLI="$( echo "${FLINK_ENV_JAVA_OPTS_CLI}" | sed -e 's/^"//'  -e 's/"$//' )"
fiif [ -z "${FLINK_SSH_OPTS}" ]; thenFLINK_SSH_OPTS=$(readFromConfig ${KEY_ENV_SSH_OPTS} "${DEFAULT_ENV_SSH_OPTS}" "${YAML_CONF}")
fi# Define ZK_HEAP if it is not already set
if [ -z "${ZK_HEAP}" ]; thenZK_HEAP=$(readFromConfig ${KEY_ZK_HEAP_MB} 0 "${YAML_CONF}")
fi# High availability
if [ -z "${HIGH_AVAILABILITY}" ]; thenHIGH_AVAILABILITY=$(readFromConfig ${KEY_HIGH_AVAILABILITY} "" "${YAML_CONF}")if [ -z "${HIGH_AVAILABILITY}" ]; then# Try deprecated valueDEPRECATED_HA=$(readFromConfig "recovery.mode" "" "${YAML_CONF}")if [ -z "${DEPRECATED_HA}" ]; thenHIGH_AVAILABILITY="none"elif [ ${DEPRECATED_HA} == "standalone" ]; then# Standalone is now 'none'HIGH_AVAILABILITY="none"elseHIGH_AVAILABILITY=${DEPRECATED_HA}fifi
fi# Arguments for the JVM. Used for job and task manager JVMs.
# DO NOT USE FOR MEMORY SETTINGS! Use conf/flink-conf.yaml with keys
# JobManagerOptions#TOTAL_PROCESS_MEMORY and TaskManagerOptions#TOTAL_PROCESS_MEMORY for that!
if [ -z "${JVM_ARGS}" ]; thenJVM_ARGS=""
fi# Check if deprecated HADOOP_HOME is set, and specify config path to HADOOP_CONF_DIR if it's empty.
if [ -z "$HADOOP_CONF_DIR" ]; thenif [ -n "$HADOOP_HOME" ]; then# HADOOP_HOME is set. Check if its a Hadoop 1.x or 2.x HADOOP_HOME pathif [ -d "$HADOOP_HOME/conf" ]; then# It's Hadoop 1.xHADOOP_CONF_DIR="$HADOOP_HOME/conf"fiif [ -d "$HADOOP_HOME/etc/hadoop" ]; then# It's Hadoop 2.2+HADOOP_CONF_DIR="$HADOOP_HOME/etc/hadoop"fifi
fi# if neither HADOOP_CONF_DIR nor HADOOP_CLASSPATH are set, use some common default (if available)
if [ -z "$HADOOP_CONF_DIR" ] && [ -z "$HADOOP_CLASSPATH" ]; thenif [ -d "/etc/hadoop/conf" ]; thenecho "Setting HADOOP_CONF_DIR=/etc/hadoop/conf because no HADOOP_CONF_DIR or HADOOP_CLASSPATH was set."HADOOP_CONF_DIR="/etc/hadoop/conf"fi
fi# Check if deprecated HBASE_HOME is set, and specify config path to HBASE_CONF_DIR if it's empty.
if [ -z "$HBASE_CONF_DIR" ]; thenif [ -n "$HBASE_HOME" ]; then# HBASE_HOME is set.if [ -d "$HBASE_HOME/conf" ]; thenHBASE_CONF_DIR="$HBASE_HOME/conf"fifi
fi# try and set HBASE_CONF_DIR to some common default if it's not set
if [ -z "$HBASE_CONF_DIR" ]; thenif [ -d "/etc/hbase/conf" ]; thenecho "Setting HBASE_CONF_DIR=/etc/hbase/conf because no HBASE_CONF_DIR was set."HBASE_CONF_DIR="/etc/hbase/conf"fi
fiINTERNAL_HADOOP_CLASSPATHS="${HADOOP_CLASSPATH}:${HADOOP_CONF_DIR}:${YARN_CONF_DIR}"if [ -n "${HBASE_CONF_DIR}" ]; thenINTERNAL_HADOOP_CLASSPATHS="${INTERNAL_HADOOP_CLASSPATHS}:${HBASE_CONF_DIR}"
fi# Auxilliary function which extracts the name of host from a line which
# also potentially includes topology information and the taskManager type
extractHostName() {# handle comments: extract first part of string (before first # character)WORKER=`echo $1 | cut -d'#' -f 1`# Extract the hostname from the network hierarchyif [[ "$WORKER" =~ ^.*/([0-9a-zA-Z.-]+)$ ]]; thenWORKER=${BASH_REMATCH[1]}fiecho $WORKER
}readMasters() {MASTERS_FILE="${FLINK_CONF_DIR}/masters"if [[ ! -f "${MASTERS_FILE}" ]]; thenecho "No masters file. Please specify masters in 'conf/masters'."exit 1fiMASTERS=()WEBUIPORTS=()MASTERS_ALL_LOCALHOST=trueGOON=truewhile $GOON; doread line || GOON=falseHOSTWEBUIPORT=$( extractHostName $line)if [ -n "$HOSTWEBUIPORT" ]; thenHOST=$(echo $HOSTWEBUIPORT | cut -f1 -d:)WEBUIPORT=$(echo $HOSTWEBUIPORT | cut -s -f2 -d:)MASTERS+=(${HOST})if [ -z "$WEBUIPORT" ]; thenWEBUIPORTS+=(0)elseWEBUIPORTS+=(${WEBUIPORT})fiif [ "${HOST}" != "localhost" ] && [ "${HOST}" != "127.0.0.1" ] ; thenMASTERS_ALL_LOCALHOST=falsefifidone < "$MASTERS_FILE"
}readWorkers() {WORKERS_FILE="${FLINK_CONF_DIR}/workers"if [[ ! -f "$WORKERS_FILE" ]]; thenecho "No workers file. Please specify workers in 'conf/workers'."exit 1fiWORKERS=()WORKERS_ALL_LOCALHOST=trueGOON=truewhile $GOON; doread line || GOON=falseHOST=$( extractHostName $line)if [ -n "$HOST" ] ; thenWORKERS+=(${HOST})if [ "${HOST}" != "localhost" ] && [ "${HOST}" != "127.0.0.1" ] ; thenWORKERS_ALL_LOCALHOST=falsefifidone < "$WORKERS_FILE"
}# starts or stops TMs on all workers
# TMWorkers start|stop
TMWorkers() {CMD=$1readWorkersif [ ${WORKERS_ALL_LOCALHOST} = true ] ; then# all-local setupfor worker in ${WORKERS[@]}; do"${FLINK_BIN_DIR}"/taskmanager.sh "${CMD}"doneelse# non-local setup# start/stop TaskManager instance(s) using pdsh (Parallel Distributed Shell) when availablecommand -v pdsh >/dev/null 2>&1if [[ $? -ne 0 ]]; thenfor worker in ${WORKERS[@]}; dossh -n $FLINK_SSH_OPTS $worker -- "nohup /bin/bash -l \"${FLINK_BIN_DIR}/taskmanager.sh\" \"${CMD}\" &"doneelsePDSH_SSH_ARGS="" PDSH_SSH_ARGS_APPEND=$FLINK_SSH_OPTS pdsh -w $(IFS=, ; echo "${WORKERS[*]}") \"nohup /bin/bash -l \"${FLINK_BIN_DIR}/taskmanager.sh\" \"${CMD}\""fifi
}runBashJavaUtilsCmd() {local cmd=$1local conf_dir=$2local class_path=$3local dynamic_args=${@:4}class_path=`manglePathList "${class_path}"`local output=`${JAVA_RUN} -classpath "${class_path}" org.apache.flink.runtime.util.bash.BashJavaUtils ${cmd} --configDir "${conf_dir}" $dynamic_args 2>&1 | tail -n 1000`if [[ $? -ne 0 ]]; thenecho "[ERROR] Cannot run BashJavaUtils to execute command ${cmd}." 1>&2# Print the output in case the user redirect the log to console.echo "$output" 1>&2exit 1fiecho "$output"
}extractExecutionResults() {local output="$1"local expected_lines="$2"local EXECUTION_PREFIX="BASH_JAVA_UTILS_EXEC_RESULT:"local execution_resultslocal num_linesexecution_results=$(echo "${output}" | grep ${EXECUTION_PREFIX})num_lines=$(echo "${execution_results}" | wc -l)# explicit check for empty result, becuase if execution_results is empty, then wc returns 1if [[ -z ${execution_results} ]]; thenecho "[ERROR] The execution result is empty." 1>&2exit 1fiif [[ ${num_lines} -ne ${expected_lines} ]]; thenecho "[ERROR] The execution results has unexpected number of lines, expected: ${expected_lines}, actual: ${num_lines}." 1>&2echo "[ERROR] An execution result line is expected following the prefix '${EXECUTION_PREFIX}'" 1>&2echo "$output" 1>&2exit 1fiecho "${execution_results//${EXECUTION_PREFIX}/}"
}extractLoggingOutputs() {local output="$1"local EXECUTION_PREFIX="BASH_JAVA_UTILS_EXEC_RESULT:"echo "${output}" | grep -v ${EXECUTION_PREFIX}
}parseJmArgsAndExportLogs() {java_utils_output=$(runBashJavaUtilsCmd GET_JM_RESOURCE_PARAMS "${FLINK_CONF_DIR}" "${FLINK_BIN_DIR}/bash-java-utils.jar:$(findFlinkDistJar)" "$@")logging_output=$(extractLoggingOutputs "${java_utils_output}")params_output=$(extractExecutionResults "${java_utils_output}" 2)if [[ $? -ne 0 ]]; thenecho "[ERROR] Could not get JVM parameters and dynamic configurations properly."echo "[ERROR] Raw output from BashJavaUtils:"echo "$java_utils_output"exit 1fijvm_params=$(echo "${params_output}" | head -n1)export JVM_ARGS="${JVM_ARGS} ${jvm_params}"export DYNAMIC_PARAMETERS=$(IFS=" " echo "${params_output}" | tail -n1)export FLINK_INHERITED_LOGS="
$FLINK_INHERITED_LOGSJM_RESOURCE_PARAMS extraction logs:
jvm_params: $jvm_params
logs: $logging_output
"
}

可以看到里面确实有各个变量的解析构造过程，具体看代码，这里不再赘述。

最后执行了一句:

# Add HADOOP_CLASSPATH to allow the usage of Hadoop file systems
exec $JAVA_RUN $JVM_ARGS $FLINK_ENV_JAVA_OPTS "${log_setting[@]}" -classpath "`manglePathList "$CC_CLASSPATH:$INTERNAL_HADOOP_CLASSPATHS"`" org.apache.flink.client.cli.CliFrontend "$@"

$JAVA_RUN从config.sh可知，其实就是Java命令。 其他的变量都是些参数， 最核心的就是这个类: 

org.apache.flink.client.cli.CliFrontend。 这个类是真正启动flink命令后执行的Java类，今天主要介绍flink命令， 后面再专门介绍这个类。