三 tomcat 启动脚本分析部分
2018-12-24 本文已影响11人
爱编程的凯哥
本章，我们将分析了tomat启动流程的shell脚本，先看下tomcat7源码的目录结构
tomcat7
看图大家都知道，
- bin是存放所有启动文件脚本的地方
- conf中存放tomcat用户自定义的配置文件
- logs存放tomcat日志
- temp存放tomcat工作时的临时文件
- webapps存放用户的web项目
- work存放jsp编译的classs文件
- java中存放了tomcat的源码
一般启动tomcat都是找到bin目录下的startup.bat(windows)下或者startup.sh(linux下)，所以要研究tomcat的启动，startup脚本是避不开的。我们今天生产常用linux服务器，所以重点看下startup.sh,先粘出来看一下
#!/bin/sh
os400=false
case "`uname`" in
OS400*) os400=true;;
esac
# resolve links - $0 may be a softlink
PRG="$0"
while [ -h "$PRG" ] ; do
ls=`ls -ld "$PRG"`
link=`expr "$ls" : '.*-> \(.*\)$'`
if expr "$link" : '/.*' > /dev/null; then
PRG="$link"
else
PRG=`dirname "$PRG"`/"$link"
fi
done
PRGDIR=`dirname "$PRG"`
EXECUTABLE=catalina.sh
# Check that target executable exists
if $os400; then
# -x will Only work on the os400 if the files are:
# 1. owned by the user
# 2. owned by the PRIMARY group of the user
# this will not work if the user belongs in secondary groups
eval
else
if [ ! -x "$PRGDIR"/"$EXECUTABLE" ]; then
echo "Cannot find $PRGDIR/$EXECUTABLE"
echo "The file is absent or does not have execute permission"
echo "This file is needed to run this program"
exit 1
fi
fi
exec "$PRGDIR"/"$EXECUTABLE" start "$@"
再来看看shutdown.sh文件
# resolve links - $0 may be a softlink
PRG="$0"
#软连接处理
while [ -h "$PRG" ] ; do
ls=`ls -ld "$PRG"`
link=`expr "$ls" : '.*-> \(.*\)$'`
if expr "$link" : '/.*' > /dev/null; then
PRG="$link"
else
PRG=`dirname "$PRG"`/"$link"
fi
done
#获取catalina.sh文件
PRGDIR=`dirname "$PRG"`
EXECUTABLE=catalina.sh
# Check that target executable exists
if [ ! -x "$PRGDIR"/"$EXECUTABLE" ]; then
echo "Cannot find $PRGDIR/$EXECUTABLE"
echo "This file is needed to run this program"
exit 1
fi
#执行catalina.sh stop命令
exec "$PRGDIR"/"$EXECUTABLE" stop "$@"
上面两个文件，我们可以看看出startup.sh和shutdown.sh作为tocmat的启动关闭脚本，作用都是包装参数，最终找到catalina.sh，执行catalina.sh文件，所以catalina.sh必定tomcat启动脚本的核心内容。catalina.sh的内容较长，有500多行，但内容除去对cygwin，os400，darwin等系统等特殊处理外，总结如下：
catalina.sh
简单看下脚本原版：
OS specific support. $var _must_ be set to either true or false.
#和startup.sh开头一样的逻辑，判断个别系统，并解决软连接时的文件问题
cygwin=false
os400=false
darwin=false
case "`uname`" in
CYGWIN*) cygwin=true;;
OS400*) os400=true;;
Darwin*) darwin=true;;
esac
# resolve links - $0 may be a softlink
PRG="$0"
while [ -h "$PRG" ]; do
ls=`ls -ld "$PRG"`
link=`expr "$ls" : '.*-> \(.*\)$'`
if expr "$link" : '/.*' > /dev/null; then
PRG="$link"
else
PRG=`dirname "$PRG"`/"$link"
fi
done
# Get standard environment variables
PRGDIR=`dirname "$PRG"`
# Only set CATALINA_HOME if not already set
#判断$CATALINA_HOME是否为空，如果为空指定catalina.sh所在目录的父级目录为CATALINA_HOME
[ -z "$CATALINA_HOME" ] && CATALINA_HOME=`cd "$PRGDIR/.." >/dev/null; pwd`
# Ensure that any user defined CLASSPATH variables are not used on startup,
# but allow them to be specified in setenv.sh, in rare case when it is needed.
#默认清空CLASSPATH，不用系统定义的，但可以用户在 setenv.sh自定义
CLASSPATH=
#${CATALINA_BASE:-$CATALINA_HOME}类似java三元运算的写法，当CATALINA_BASE为空时，用$CATALINA_HOME，
#注CATALINA_BASE表示用户的工作目录，每个应用不一样，$CATALINA_HOME为tomcat的安装目录，多个web是可以公用的
SETENVPATH="${CATALINA_BASE:-$CATALINA_HOME}"
#执行setenv.sh文件，主要作用是配置用户自定义的环境变量，如jvm配置，临时空间配置等等，一般都在这配置
if [ -r "$SETENVPATH/bin/setenv.sh" ]; then
. "$SETENVPATH/bin/setenv.sh"
elif [ -r "$CATALINA_HOME/bin/setenv.sh" ]; then
. "$CATALINA_HOME/bin/setenv.sh"
fi
# For Cygwin, ensure paths are in UNIX format before anything is touched
#对应Cygwin和OS400系统的一些配置定制
if $cygwin; then
[ -n "$JAVA_HOME" ] && JAVA_HOME=`cygpath --unix "$JAVA_HOME"`
[ -n "$JRE_HOME" ] && JRE_HOME=`cygpath --unix "$JRE_HOME"`
[ -n "$CATALINA_HOME" ] && CATALINA_HOME=`cygpath --unix "$CATALINA_HOME"`
[ -n "$CATALINA_BASE" ] && CATALINA_BASE=`cygpath --unix "$CATALINA_BASE"`
[ -n "$CLASSPATH" ] && CLASSPATH=`cygpath --path --unix "$CLASSPATH"`
fi
# For OS400
if $os400; then
# Set job priority to standard for interactive (interactive - 6) by using
# the interactive priority - 6, the helper threads that respond to requests
# will be running at the same priority as interactive jobs.
COMMAND='chgjob job('$JOBNAME') runpty(6)'
system $COMMAND
# Enable multi threading
export QIBM_MULTI_THREADED=Y
fi
# Get standard Java environment variables
if $os400; then
# -r will Only work on the os400 if the files are:
# 1. owned by the user
# 2. owned by the PRIMARY group of the user
# this will not work if the user belongs in secondary groups
BASEDIR="$CATALINA_HOME"
. "$CATALINA_HOME"/bin/setclasspath.sh
else
#对于linux系统默认采用setclasspath.sh配置文件配置classpath，找到java_home,会通过whichis java找到jre
if [ -r "$CATALINA_HOME"/bin/setclasspath.sh ]; then
BASEDIR="$CATALINA_HOME"
. "$CATALINA_HOME"/bin/setclasspath.sh
else
echo "Cannot find $CATALINA_HOME/bin/setclasspath.sh"
echo "This file is needed to run this program"
exit 1
fi
fi
# Add on extra jar files to CLASSPATH
if [ ! -z "$CLASSPATH" ] ; then
CLASSPATH="$CLASSPATH":
fi
#将bootstrap.jar放入classpath中，里面包含了tomcat的启用源码
CLASSPATH="$CLASSPATH""$CATALINA_HOME"/bin/bootstrap.jar
#用户不自定义配置$CATALINA_BASE时，将与$CATALINA_HOME保持一致
if [ -z "$CATALINA_BASE" ] ; then
CATALINA_BASE="$CATALINA_HOME"
fi
#tomcat默认将启动日志打印到/logs/catalina.out中
if [ -z "$CATALINA_OUT" ] ; then
CATALINA_OUT="$CATALINA_BASE"/logs/catalina.out
fi
if [ -z "$CATALINA_TMPDIR" ] ; then
# Define the java.io.tmpdir to use for Catalina
#tomcat默认临时目录为/temp目录
CATALINA_TMPDIR="$CATALINA_BASE"/temp
fi
# Add tomcat-juli.jar to classpath
# tomcat-juli.jar can be over-ridden per instance
#加载tomcat-juli包，主要处理tomcat的自身日志
if [ -r "$CATALINA_BASE/bin/tomcat-juli.jar" ] ; then
CLASSPATH=$CLASSPATH:$CATALINA_BASE/bin/tomcat-juli.jar
else
CLASSPATH=$CLASSPATH:$CATALINA_HOME/bin/tomcat-juli.jar
fi
# Bugzilla 37848: When no TTY is available, don't output to console
#判断系统tty是否可用，不可用，将不会在控制台打印信息
have_tty=0
if [ "`tty`" != "not a tty" ]; then
have_tty=1
fi
# For Cygwin, switch paths to Windows format before running java
if $cygwin; then
JAVA_HOME=`cygpath --absolute --windows "$JAVA_HOME"`
JRE_HOME=`cygpath --absolute --windows "$JRE_HOME"`
CATALINA_HOME=`cygpath --absolute --windows "$CATALINA_HOME"`
CATALINA_BASE=`cygpath --absolute --windows "$CATALINA_BASE"`
CATALINA_TMPDIR=`cygpath --absolute --windows "$CATALINA_TMPDIR"`
CLASSPATH=`cygpath --path --windows "$CLASSPATH"`
JAVA_ENDORSED_DIRS=`cygpath --path --windows "$JAVA_ENDORSED_DIRS"`
fi
# Set juli LogManager config file if it is present and an override has not been issued
#默认的log的配置文件取/conf/logging.properties
if [ -z "$LOGGING_CONFIG" ]; then
if [ -r "$CATALINA_BASE"/conf/logging.properties ]; then
LOGGING_CONFIG="-Djava.util.logging.config.file=$CATALINA_BASE/conf/logging.properties"
else
# Bugzilla 45585
LOGGING_CONFIG="-Dnop"
fi
fi
#配置java.util.logging.manager日志管理类默认取org.apache.juli.ClassLoaderLogManager
if [ -z "$LOGGING_MANAGER" ]; then
JAVA_OPTS="$JAVA_OPTS -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager"
else
JAVA_OPTS="$JAVA_OPTS $LOGGING_MANAGER"
fi
# Uncomment the following line to make the umask available when using the
# org.apache.catalina.security.SecurityListener
#JAVA_OPTS="$JAVA_OPTS -Dorg.apache.catalina.security.SecurityListener.UMASK=`umask`"
# ----- Execute The Requested Command -----------------------------------------
# Bugzilla 37848: only output this if we have a TTY
if [ $have_tty -eq 1 ]; then
echo "Using CATALINA_BASE: $CATALINA_BASE"
echo "Using CATALINA_HOME: $CATALINA_HOME"
echo "Using CATALINA_TMPDIR: $CATALINA_TMPDIR"
if [ "$1" = "debug" ] ; then
echo "Using JAVA_HOME: $JAVA_HOME"
else
echo "Using JRE_HOME: $JRE_HOME"
fi
echo "Using CLASSPATH: $CLASSPATH"
if [ ! -z "$CATALINA_PID" ]; then
echo "Using CATALINA_PID: $CATALINA_PID"
fi
fi
#是否开启jpda远程调试功能，如果开启默认端口8000
if [ "$1" = "jpda" ] ; then
if [ -z "$JPDA_TRANSPORT" ]; then
JPDA_TRANSPORT="dt_socket"
fi
if [ -z "$JPDA_ADDRESS" ]; then
JPDA_ADDRESS="8000"
fi
if [ -z "$JPDA_SUSPEND" ]; then
JPDA_SUSPEND="n"
fi
if [ -z "$JPDA_OPTS" ]; then
JPDA_OPTS="-agentlib:jdwp=transport=$JPDA_TRANSPORT,address=$JPDA_ADDRESS,server=y,suspend=$JPDA_SUSPEND"
fi
CATALINA_OPTS="$CATALINA_OPTS $JPDA_OPTS"
#参数前移一位
shift
fi
#tocmat开启debug模式启动
if [ "$1" = "debug" ] ; then
if $os400; then
echo "Debug command not available on OS400"
exit 1
else
#参数每次前移一位，每次处理$1
shift
#当tomcat启动时配置了security参数，表示tomcat启动以security模式启动，对应的安全策略配置文件为catalina.policy
if [ "$1" = "-security" ] ; then
if [ $have_tty -eq 1 ]; then
echo "Using Security Manager"
fi
shift
exec "$_RUNJDB" "$LOGGING_CONFIG" $JAVA_OPTS $CATALINA_OPTS \
-Djava.endorsed.dirs="$JAVA_ENDORSED_DIRS" -classpath "$CLASSPATH" \
-sourcepath "$CATALINA_HOME"/../../java \
-Djava.security.manager \
-Djava.security.policy=="$CATALINA_BASE"/conf/catalina.policy \
-Dcatalina.base="$CATALINA_BASE" \
-Dcatalina.home="$CATALINA_HOME" \
-Djava.io.tmpdir="$CATALINA_TMPDIR" \
org.apache.catalina.startup.Bootstrap "$@" start
else
exec "$_RUNJDB" "$LOGGING_CONFIG" $JAVA_OPTS $CATALINA_OPTS \
-Djava.endorsed.dirs="$JAVA_ENDORSED_DIRS" -classpath "$CLASSPATH" \
-sourcepath "$CATALINA_HOME"/../../java \
-Dcatalina.base="$CATALINA_BASE" \
-Dcatalina.home="$CATALINA_HOME" \
-Djava.io.tmpdir="$CATALINA_TMPDIR" \
org.apache.catalina.startup.Bootstrap "$@" start
fi
fi
#run参数直接启动tomcat
elif [ "$1" = "run" ]; then
shift
if [ "$1" = "-security" ] ; then
if [ $have_tty -eq 1 ]; then
echo "Using Security Manager"
fi
shift
eval \"$_RUNJAVA\" \"$LOGGING_CONFIG\" $JAVA_OPTS $CATALINA_OPTS \
-Djava.endorsed.dirs=\"$JAVA_ENDORSED_DIRS\" -classpath \"$CLASSPATH\" \
-Djava.security.manager \
-Djava.security.policy==\"$CATALINA_BASE/conf/catalina.policy\" \
-Dcatalina.base=\"$CATALINA_BASE\" \
-Dcatalina.home=\"$CATALINA_HOME\" \
-Djava.io.tmpdir=\"$CATALINA_TMPDIR\" \
org.apache.catalina.startup.Bootstrap "$@" start
else
eval \"$_RUNJAVA\" \"$LOGGING_CONFIG\" $JAVA_OPTS $CATALINA_OPTS \
-Djava.endorsed.dirs=\"$JAVA_ENDORSED_DIRS\" -classpath \"$CLASSPATH\" \
-Dcatalina.base=\"$CATALINA_BASE\" \
-Dcatalina.home=\"$CATALINA_HOME\" \
-Djava.io.tmpdir=\"$CATALINA_TMPDIR\" \
org.apache.catalina.startup.Bootstrap "$@" start
fi
#start参数启动tomcat
elif [ "$1" = "start" ] ; then
#处理$CATALINA_PID文件，如果有存在且还在运行，则异常，正常情况下
if [ ! -z "$CATALINA_PID" ]; then
#判断文件是否为常规文件
if [ -f "$CATALINA_PID" ]; then
#如果文件是否为非0文件
if [ -s "$CATALINA_PID" ]; then
echo "Existing PID file found during start."
#判断文件是否可读
if [ -r "$CATALINA_PID" ]; then
#读取$CATALINA_PID文件内容
PID=`cat "$CATALINA_PID"`
#查看进程，
ps -p $PID >/dev/null 2>&1
if [ $? -eq 0 ] ; then
echo "Tomcat appears to still be running with PID $PID. Start aborted."
exit 1
else
echo "Removing/clearing stale PID file."
rm -f "$CATALINA_PID" >/dev/null 2>&1
if [ $? != 0 ]; then
if [ -w "$CATALINA_PID" ]; then
cat /dev/null > "$CATALINA_PID"
else
echo "Unable to remove or clear stale PID file. Start aborted."
exit 1
fi
fi
fi
else
echo "Unable to read PID file. Start aborted."
exit 1
fi
else
rm -f "$CATALINA_PID" >/dev/null 2>&1
if [ $? != 0 ]; then
if [ ! -w "$CATALINA_PID" ]; then
echo "Unable to remove or write to empty PID file. Start aborted."
exit 1
fi
fi
fi
fi
fi
shift
#新建$CATALINA_OUT日志文件，启动tomcat输出到此文件中，
touch "$CATALINA_OUT"
if [ "$1" = "-security" ] ; then
if [ $have_tty -eq 1 ]; then
echo "Using Security Manager"
fi
shift
eval \"$_RUNJAVA\" \"$LOGGING_CONFIG\" $JAVA_OPTS $CATALINA_OPTS \
-Djava.endorsed.dirs=\"$JAVA_ENDORSED_DIRS\" -classpath \"$CLASSPATH\" \
-Djava.security.manager \
-Djava.security.policy==\"$CATALINA_BASE/conf/catalina.policy\" \
-Dcatalina.base=\"$CATALINA_BASE\" \
-Dcatalina.home=\"$CATALINA_HOME\" \
-Djava.io.tmpdir=\"$CATALINA_TMPDIR\" \
org.apache.catalina.startup.Bootstrap "$@" start \
>> "$CATALINA_OUT" 2>&1 "&"
else
eval \"$_RUNJAVA\" \"$LOGGING_CONFIG\" $JAVA_OPTS $CATALINA_OPTS \
-Djava.endorsed.dirs=\"$JAVA_ENDORSED_DIRS\" -classpath \"$CLASSPATH\" \
-Dcatalina.base=\"$CATALINA_BASE\" \
-Dcatalina.home=\"$CATALINA_HOME\" \
-Djava.io.tmpdir=\"$CATALINA_TMPDIR\" \
org.apache.catalina.startup.Bootstrap "$@" start \
>> "$CATALINA_OUT" 2>&1 "&"
fi
#原有$CATALINA_PID文件不存在
if [ ! -z "$CATALINA_PID" ]; then
#$!获取上一次后台进程号，即刚才启动的tomcat进程号，存入文件
echo $! > "$CATALINA_PID"
fi
#如果传入stop命令时，处理关闭逻辑
elif [ "$1" = "stop" ] ; then
shift
SLEEP=5
if [ ! -z "$1" ]; then
#指定睡眠时间的逻辑
echo $1 | grep "[^0-9]" >/dev/null 2>&1
if [ $? -gt 0 ]; then
SLEEP=$1
shift
fi
fi
FORCE=0
if [ "$1" = "-force" ]; then
shift
FORCE=1
fi
if [ ! -z "$CATALINA_PID" ]; then
if [ -s "$CATALINA_PID" ]; then
if [ -f "$CATALINA_PID" ]; then
kill -0 `cat "$CATALINA_PID"` >/dev/null 2>&1
if [ $? -gt 0 ]; then
echo "PID file found but no matching process was found. Stop aborted."
exit 1
fi
else
echo "\$CATALINA_PID was set but the specified file does not exist. Is Tomcat running? Stop aborted."
exit 1
fi
else
echo "PID file is empty and has been ignored."
fi
fi
#关闭tomcat逻辑
eval \"$_RUNJAVA\" $JAVA_OPTS \
-Djava.endorsed.dirs=\"$JAVA_ENDORSED_DIRS\" -classpath \"$CLASSPATH\" \
-Dcatalina.base=\"$CATALINA_BASE\" \
-Dcatalina.home=\"$CATALINA_HOME\" \
-Djava.io.tmpdir=\"$CATALINA_TMPDIR\" \
org.apache.catalina.startup.Bootstrap "$@" stop
if [ ! -z "$CATALINA_PID" ]; then
if [ -f "$CATALINA_PID" ]; then
while [ $SLEEP -ge 0 ]; do
kill -0 `cat "$CATALINA_PID"` >/dev/null 2>&1
if [ $? -gt 0 ]; then
rm -f "$CATALINA_PID" >/dev/null 2>&1
if [ $? != 0 ]; then
if [ -w "$CATALINA_PID" ]; then
cat /dev/null > "$CATALINA_PID"
else
echo "Tomcat stopped but the PID file could not be removed or cleared."
fi
fi
break
fi
if [ $SLEEP -gt 0 ]; then
sleep 1
fi
if [ $SLEEP -eq 0 ]; then
if [ $FORCE -eq 0 ]; then
echo "Tomcat did not stop in time. PID file was not removed."
fi
fi
SLEEP=`expr $SLEEP - 1 `
done
fi
fi
if [ $FORCE -eq 1 ]; then
if [ -z "$CATALINA_PID" ]; then
echo "Kill failed: \$CATALINA_PID not set"
else
if [ -f "$CATALINA_PID" ]; then
PID=`cat "$CATALINA_PID"`
echo "Killing Tomcat with the PID: $PID"
kill -9 $PID
rm -f "$CATALINA_PID" >/dev/null 2>&1
if [ $? != 0 ]; then
echo "Tomcat was killed but the PID file could not be removed."
fi
fi
fi
fi
elif [ "$1" = "configtest" ] ; then
eval \"$_RUNJAVA\" $JAVA_OPTS $CATALINA_OPTS \
-Djava.endorsed.dirs=\"$JAVA_ENDORSED_DIRS\" -classpath \"$CLASSPATH\" \
-Dcatalina.base=\"$CATALINA_BASE\" \
-Dcatalina.home=\"$CATALINA_HOME\" \
-Djava.io.tmpdir=\"$CATALINA_TMPDIR\" \
org.apache.catalina.startup.Bootstrap configtest
exit $?
elif [ "$1" = "version" ] ; then
"$_RUNJAVA" \
-classpath "$CATALINA_HOME/lib/catalina.jar" \
org.apache.catalina.util.ServerInfo
else
echo "Usage: catalina.sh ( commands ... )"
echo "commands:"
if $os400; then
echo " debug Start Catalina in a debugger (not available on OS400)"
echo " debug -security Debug Catalina with a security manager (not available on OS400)"
else
echo " debug Start Catalina in a debugger"
echo " debug -security Debug Catalina with a security manager"
fi
echo " jpda start Start Catalina under JPDA debugger"
echo " run Start Catalina in the current window"
echo " run -security Start in the current window with security manager"
echo " start Start Catalina in a separate window"
echo " start -security Start in a separate window with security manager"
echo " stop Stop Catalina, waiting up to 5 seconds for the process to end"
echo " stop n Stop Catalina, waiting up to n seconds for the process to end"
echo " stop -force Stop Catalina, wait up to 5 seconds and then use kill -KILL if still running"
echo " stop n -force Stop Catalina, wait up to n seconds and then use kill -KILL if still running"
echo " version What version of tomcat are you running?"
echo "Note: Waiting for the process to end and use of the -force option require that \$CATALINA_PID is defined"
exit 1
fi
如上，我们get的到的知识点有哪些呢？
- 自定义的java变量可以定义到setenv.sh中，如我的一个应用配置
#-D属性名的方式，在java代码中可以通过getSystem获取到
JAVA_OPTS="$JAVA_OPTS -Ddbconfigpath=/apps/dbpah/ -Djava.net.preferIPv4Stack=true -Xshare:off -Dhostname=`hostname`"
JAVA_OPTS="$JAVA_OPTS -Xms256m -Xmx1024m -XX:PermSize=64m -XX:MaxPermSize=512m"
JAVA_OPTS="$JAVA_OPTS -Djava.security.egd=file:/dev/./urandom"
JAVA_OPTS="$JAVA_OPTS
-XX:+UseBiasedLocking
-XX:+UseConcMarkSweepGC
-XX:+UseParNewGC
-XX:+CMSParallelRemarkEnabled
-XX:+UseCMSCompactAtFullCollection
-XX:LargePageSizeInBytes=128m
-XX:+UseFastAccessorMethods
-XX:+UseCMSInitiatingOccupancyOnly
-Djava.awt.headless=true"
JAVA_OPTS="$JAVA_OPTS -Dsun.net.inetaddr.ttl=-1 -Dappname=jcbs-web"
- 最后启动关闭的代码逻辑到了org.apache.catalina.startup.Bootstrap类的main方法上，然后通过命令参数start、stop等进行操作。
下一章，我们开始分析tomcat启动的源码org.apache.catalina.startup.Bootstrap类。
目录: tomcat 源码学习系列
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