jvm 诊断工具

#!/bin/bash
# @Function
# Find out the highest cpu consumed threads of java, and print the stack of these threads.
#
# @Usage
#   $ ./show-busy-java-threads
#
# @online-doc https://github.com/oldratlee/useful-scripts/blob/master/docs/java.md#-show-busy-java-threads
# @author Jerry Lee (oldratlee at gmail dot com)
# @author superhj1987 (superhj1987 at 126 dot com)
#@author  scan  20200509
##readonly用来定义只读变量，一旦使用readonly定义的变量在脚本中就不能更改

## 获取脚本名字
readonly PROG="`basename $0`"

##-a：定义只读数组变量；
##echo ${COMMAND_LINE[0]}
readonly -a COMMAND_LINE=("$0" "$@")
# Get current user name via whoami command
#   See https://www.lifewire.com/current-linux-user-whoami-command-3867579
# Because if run command by `sudo -u`, env var $USER is not rewritten/correct, just inherited from outside!
readonly USER="`whoami`"

################################################################################
# util functions
################################################################################

# NOTE: $'foo' is the escape sequence syntax of bash
##echo "$ec[1;31m$@$eend" 定义颜色的始末
##$@ 所有参数的内容
readonly ec=$'33' # escape char
readonly eend=$'33[0m' # escape end

colorEcho() {
    local color=$1
    shift

    # if stdout is console, turn on color output.
    [ -t 1 ] && echo "$ec[1;${color}m$@$eend" || echo "$@"
}

colorPrint() {
    local color=$1
    shift

    colorEcho "$color" "$@"
    [ -n "$append_file" -a -w "$append_file" ] && echo "$@" >> "$append_file"
    [ -n "$store_dir" -a -w "$store_dir" ] && echo "$@" >> "${store_file_prefix}$PROG"
}

normalPrint() {
    echo "$@"
    [ -n "$append_file" -a -w "$append_file" ] && echo "$@" >> "$append_file"
    [ -n "$store_dir" -a -w "$store_dir" ] && echo "$@" >> "${store_file_prefix}$PROG"
}

redPrint() {
    colorPrint 31 "$@"
}

greenPrint() {
    colorPrint 32 "$@"
}

yellowPrint() {
    colorPrint 33 "$@"
}

bluePrint() {
    colorPrint 36 "$@"
}

die() {
    redPrint "Error: $@" 1>&2
    exit 1
}

logAndRun() {
    echo "$@"
    echo
    "$@"
}

logAndCat() {
    echo "$@"
    echo
    cat
}

usage() {
    #Remove any current binding for keyseq.
	#
    local -r exit_code="$1"
    shift
	# -n the length of STRING is nonzero
	#-a both EXPRESSION1 and EXPRESSION2 are true
	#
    [ -n "$exit_code" -a "$exit_code" != 0 ] && local -r out=/dev/stderr || local -r out=/dev/stdout

    (( $# > 0 )) && { echo "$@"; echo; } > $out

    > $out cat <<EOF
Usage: ${PROG} [OPTION]... [delay [count]]
Find out the highest cpu consumed threads of java, and print the stack of these threads.
Example:
  ${PROG}       # show busy java threads info
  ${PROG} 1     # update every 1 second, (stop by eg: CTRL+C)
  ${PROG} 3 10  # update every 3 seconds, update 10 times
Output control:
  -p, --pid <java pid>      find out the highest cpu consumed threads from
                            the specified java process, default from all java process.
  -c, --count <num>         set the thread count to show, default is 5.
  -a, --append-file <file>  specifies the file to append output as log.
  -S, --store-dir <dir>     specifies the directory for storing intermediate files, and keep files.
                            default store intermediate files at tmp dir, and auto remove after run.
                            use this option to keep files so as to review jstack/top/ps output later.
  delay                     the delay between updates in seconds.
  count                     the number of updates.
                            delay/count arguments imitates the style of vmstat command.
jstack control:
  -s, --jstack-path <path>  specifies the path of jstack command.
  -F, --force               set jstack to force a thread dump.
                            use when jstack <pid> does not respond (process is hung).
  -m, --mix-native-frames   set jstack to print both java and native frames (mixed mode).
  -l, --lock-info           set jstack with long listing. Prints additional information about locks.
CPU usage calculation control:
  -d, --top-delay           specifies the delay between top samples, default is 0.5 (second).
                            get thread cpu percentage during this delay interval.
                            more info see top -d option. eg: -d 1 (1 second).
  -P, --use-ps              use ps command to find busy thread(cpu usage) instead of top command,
                            default use top command, because cpu usage of ps command is expressed as
                            the percentage of time spent running during the *entire lifetime*
                            of a process, this is not ideal in general.
Miscellaneous:
  -h, --help                display this help and exit.
EOF

    exit $exit_code
}

################################################################################
# Check os support
################################################################################

uname | grep '^Linux' -q || die "$PROG only support Linux, not support `uname` yet!"

################################################################################
# parse options
################################################################################

# NOTE: ARGS can not be declared as readonly!!
# readonly declaration make exit code of assignment to be always 0, aka. the exit code of `getopt` in subshell is discarded.
#   tested on bash 4.2.46
##-n, --name <程序名>         将错误报告给的程序名
##-a --alternative            允许长选项以 - 开始

## -l, --longoptions <长选项>  要识别的长选项
ARGS=`getopt -n "$PROG" -a -o p:c:a:s:S:Pd:Fmlh -l count:,pid:,append-file:,jstack-path:,store-dir:,use-ps,top-delay:,force,mix-native-frames,lock-info,help -- "$@"`
[ $? -ne 0 ] && { echo; usage 1; }
eval set -- "${ARGS}"

while true; do
    case "$1" in
    -c|--count)
        count="$2"
        shift 2
        ;;
    -p|--pid)
        pid="$2"
        shift 2
        ;;
    -a|--append-file)
        append_file="$2"
        shift 2
        ;;
    -s|--jstack-path)
        jstack_path="$2"
        shift 2
        ;;
    -S|--store-dir)
        store_dir="$2"
        shift 2
        ;;
    -P|--use-ps)
        use_ps=true
        shift
        ;;
    -d|--top-delay)
        top_delay="$2"
        shift 2
        ;;
    -F|--force)
        force=-F
        shift
        ;;
    -m|--mix-native-frames)
        mix_native_frames=-m
        shift
        ;;
    -l|--lock-info)
        more_lock_info=-l
        shift
        ;;
    -h|--help)
        usage
        ;;
    --)
        shift
        break
        ;;
    esac
done

##如果count有定义,那么就是count对应的值,否则就是5
count=${count:-5}

##如果$1存在就是$1,否则就是0
update_delay=${1:-0}
# -z the length of STRING is zero,
[ -z "$1" ] && update_count=1 || update_count=${2:-0}
(( update_count < 0 )) && update_count=0


##如果top_delay 定义,那么就是top_delay,否则就是0.5  
top_delay=${top_delay:-0.5}

##如果use_ps定义,那么就是use_ps,否则就是false
use_ps=${use_ps:-false}

# check the directory of append-file(-a) mode, create if not exsit.

##创建输出文件
##-n the length of STRING is nonzero
##
if [ -n "$append_file" ]; then
##-e  FILE exists 文件存在
    if [ -e "$append_file" ]; then
	##-f FILE exists and is a regular file 文件存在且是一个普通文件
        [ -f "$append_file" ] || die "$append_file(specified by option -a, for storing run output files) exists but is not a file!"
    ##-w 文件存在且FILE exists and write permission is granted    
		[ -w "$append_file" ] || die "file $append_file(specified by option -a, for storing run output files) exists but is not writable!"
    else
	    ## 获取文件对应的目录
        append_file_dir="$(dirname "$append_file")"
		##文件存在
        if [ -e "$append_file_dir" ]; then
		
		##-d  FILE exists and is a directory
            [ -d "$append_file_dir" ] || die "directory $append_file_dir(specified by option -a, for storing run output files) exists but is not a directory!"
            ##-w FILE exists and write permission is granted
			[ -w "$append_file_dir" ] || die "directory $append_file_dir(specified by option -a, for storing run output files) exists but is not writable!"
        else
            mkdir -p "$append_file_dir" || die "fail to create directory $append_file_dir(specified by option -a, for storing run output files)!"
        fi
    fi
fi

# check store directory(-S) mode, create directory if not exsit.
##-n the length of STRING is nonzero
if [ -n "$store_dir" ]; then
##-e   FILE exists
    if [ -e "$store_dir" ]; then
	##-d FILE exists and is a directory
        [ -d "$store_dir" ] || die "$store_dir(specified by option -S, for storing output files) exists but is not a directory!"
    ##    
		[ -w "$store_dir" ] || die "directory $store_dir(specified by option -S, for storing output files) exists but is not writable!"
    else
        mkdir -p "$store_dir" || die "fail to create directory $store_dir(specified by option -S, for storing output files)!"
    fi
fi

################################################################################
# check the existence of jstack command
################################################################################
##-n the length of STRING is nonzero
if [ -n "$jstack_path" ]; then
     ##  FILE exists and is a regular file
    [ -f "$jstack_path" ] || die "$jstack_path is NOT found!"
	##  FILE exists and execute (or search) permission is granted
    [ -x "$jstack_path" ] || die "$jstack_path is NOT executalbe!"
elif which jstack &> /dev/null; then
    jstack_path="`which jstack`"
else
    [ -n "$JAVA_HOME" ] || die "jstack not found on PATH and No JAVA_HOME setting! Use -s option set jstack path manually."
    [ -f "$JAVA_HOME/bin/jstack" ] || die "jstack not found on PATH and $JAVA_HOME/bin/jstack($JAVA_HOME/bin/jstack) file does NOT exists! Use -s option set jstack path manually."
    [ -x "$JAVA_HOME/bin/jstack" ] || die "jstack not found on PATH and $JAVA_HOME/bin/jstack($JAVA_HOME/bin/jstack) is NOT executalbe! Use -s option set jstack path manually."
    jstack_path="$JAVA_HOME/bin/jstack"
fi

################################################################################
# biz logic
################################################################################

readonly run_timestamp="`date "+%Y-%m-%d_%H:%M:%S.%N"`"
readonly uuid="${PROG}_${run_timestamp}_${RANDOM}_$$"

readonly tmp_store_dir="/tmp/${uuid}"
##-n the length of STRING is nonzero
if [ -n "$store_dir" ]; then
    readonly store_file_prefix="$store_dir/${run_timestamp}_"
else
    readonly store_file_prefix="$tmp_store_dir/${run_timestamp}_"
fi
mkdir -p "$tmp_store_dir"

cleanupWhenExit() {
    rm -rf "$tmp_store_dir" &> /dev/null
}
trap "cleanupWhenExit" EXIT

headInfo() {
    colorEcho "0;34;42" ================================================================================
    echo "$(date "+%Y-%m-%d %H:%M:%S.%N") [$(( i + 1 ))/$update_count]: ${COMMAND_LINE[@]}"
    colorEcho "0;34;42" ================================================================================
    echo
}

## 传了pid,就指定了pid  
if [ -n "${pid}" ]; then
    readonly ps_process_select_options="-p $pid"
else
##-C  这将选择在cmdlist中给定可执行名称的进程
    readonly ps_process_select_options="-C java -C jsvc"
fi

# output field: pid, thread id(lwp), pcpu, user
#   order by pcpu(percentage of cpu usage)
findBusyJavaThreadsByPs() {
    # 1. sort by %cpu by ps option `--sort -pcpu`
    # 2. use wide output(unlimited width) by ps option `-ww`
    #    avoid trunk user column to username_fo+ or $uid alike
	##-w Wide output. Use this option twice for unlimited width.
	##-L Show threads, possibly with LWP and NLWP columns
	##-o  选项允许您指定在运行 ps 命令时显示哪些列
	##LWP (thread ID) columns 
	##pcpu cpu utilization
	
	##    --sort spec     specify sorting order. Sorting syntax is [+|-]key[,[+|-]key[,...]] 
	##Choose a multi-letter key from the STANDARD FORMAT SPECIFIERS section. The "+" is
    ##默认是递增                  
    ##optional since default direction is increasing numerical or
    ##	lexicographic order. Identical to k. For example: ps jax --sort=uid,-ppid,+pid
					   
					   
    local -a ps_cmd_line=(ps $ps_process_select_options -wwLo pid,lwp,pcpu,user --sort -pcpu --no-headers)
    local -r ps_out="$("${ps_cmd_line[@]}")"
    if [ -n "$store_dir" ]; then
        echo "$ps_out" | logAndCat "${ps_cmd_line[@]}" > "${store_file_prefix}$(( i + 1 ))_ps"
    fi
    ##modifyby  scan
	##
    #echo "$ps_out" | head -n "${count}"
	echo "$ps_out" |  sort -rk3 |head -n "${count}"
}

# top with output field: thread id, %cpu
__top_threadId_cpu() {
    # 1. sort by %cpu by top option `-o %CPU`
    #    unfortunately, top version 3.2 does not support -o option(supports from top version 3.3+),
    #    use
    #       HOME="$tmp_store_dir" top -H -b -n 1
    #    combined
    #       sort
    #    instead of
    #       HOME="$tmp_store_dir" top -H -b -n 1 -o '%CPU'
    # 2. change HOME env var when run top,
    #    so as to prevent top command output format being change by .toprc user config file unexpectedly
    # 3. use option `-d 0.5`(update interval 0.5 second) and `-n 2`(update 2 times),
    #    and use second time update data to get cpu percentage of thread in 0.5 second interval
    # 4. top v3.3, there is 1 black line between 2 update;
    #    but top v3.2, there is 2 blank lines between 2 update!
	##-a 只读数组
	##-H： 设置线程模式  -b Starts top in ’Batch mode’ -d: 启动时设置刷新时间间隔 -n: n : 更新的次数，完成后将会退出 top
    local -a top_cmd_line=(top -H -b -d $top_delay -n 2)
	##${nums[@]} 获取数组中的所有元素
	##切换top运行目录
	## 获取cpu最高的线程
    local -r top_out=$(HOME="$tmp_store_dir" "${top_cmd_line[@]}")
    if [ -n "$store_dir" ]; then
        echo "$top_out" | logAndCat "${top_cmd_line[@]}" > "${store_file_prefix}$(( i + 1 ))_top"
    fi
    #只输出java进程,输出线程号,CPU 字段
    echo "$top_out" |
        awk 'BEGIN { blockIndex = 0; currentLineHasText = 0; prevLineHasText = 0; } {
            currentLineHasText = ($0 != "")
            if (prevLineHasText && !currentLineHasText)
                blockIndex++    # from text line to empty line, increase block index
            if (blockIndex == 3 && ($NF == "java" || $NF == "jsvc"))   # $NF(last field) is command field
                # only print 4th text block(blockIndex == 3), aka. process info of second top update
                print $1 " " $9     # $1 is thread id field, $9 is %cpu field
            prevLineHasText = currentLineHasText    # update prevLineHasText
        }' | sort -k2,2nr
}

__complete_pid_user_by_ps() {
    # ps output field: pid, thread id(lwp), user
    local -a ps_cmd_line=(ps $ps_process_select_options -wwLo pid,lwp,user --no-headers)
    local -r ps_out="$("${ps_cmd_line[@]}")"
	##-n 非空
    if [ -n "$store_dir" ]; then
        echo "$ps_out" | logAndCat "${ps_cmd_line[@]}" > "${store_file_prefix}$(( i + 1 ))_ps"
    fi

    local idx=0
    local -a line
    ##从__top_threadId_cpu 函数读入线程号,cpu
    while IFS=" " read -a line ; do
        (( idx < count )) || break

        local threadId="${line[0]}"
		#echo $threadId
        local pcpu="${line[1]}"
		#echo $pcpu

        # output field: pid, threadId, pcpu, user
		##通过线程号关联
		## $1 进程号 $2线程号 $3用户
		## 判断$2==threadId  
        local output_fields="$( echo "$ps_out" |
            awk -v "threadId=$threadId" -v "pcpu=$pcpu" '$2==threadId {
                printf "%s %s %s %s
", $1, threadId, pcpu, $3; exit
            }' )"
        if [ -n "$output_fields" ]; then
            (( idx++ ))
            echo "$output_fields"
        fi
    done
}

# output format is same as function findBusyJavaThreadsByPs
#| 第一个命令command 1执行的结果作为command2的输入传给command 2
findBusyJavaThreadsByTop() {

    __top_threadId_cpu | __complete_pid_user_by_ps
}

printStackOfThreads() {
    local -a line
    local idx=0
	redPrint "使用的JVM工具路径:"
		echo $jstack_path
		sleep 2
    while IFS=" " read -a line ; do
	    ##打印数组内容
		redPrint "pid,lwp,pcpu,user" 
	    redPrint ${line[*]}
        local pid="${line[0]}"
        local threadId="${line[1]}"
        local threadId0x="0x`printf %x ${threadId}`"
        local pcpu="${line[2]}"
        local user="${line[3]}"
        
        (( idx++ ))
        local jstackFile="${store_file_prefix}$(( i + 1 ))_jstack_${pid}"
        [ -f "${jstackFile}" ] || {
            local -a jstack_cmd_line=( "$jstack_path" ${force} $mix_native_frames $more_lock_info ${pid} )
            if [ "${user}" == "${USER}" ]; then
                # run without sudo, when java process user is current user
                logAndRun "${jstack_cmd_line[@]}" > ${jstackFile}
            elif [ $UID == 0 ]; then
                # if java process user is not current user, must run jstack with sudo
                logAndRun sudo -u "${user}" "${jstack_cmd_line[@]}" > ${jstackFile}
            else
                # current user is not root user, so can not run with sudo; print error message and rerun suggestion
                redPrint "[$idx] Fail to jstack busy(${pcpu}%) thread(${threadId}/${threadId0x}) stack of java process(${pid}) under user(${user})."
                redPrint "User of java process($user) is not current user($USER), need sudo to rerun:"
                yellowPrint "    sudo ${COMMAND_LINE[@]}"
                normalPrint
                continue
            fi || {
                redPrint "[$idx] Fail to jstack busy(${pcpu}%) thread(${threadId}/${threadId0x}) stack of java process(${pid}) under user(${user})."
                normalPrint
                rm "${jstackFile}" &> /dev/null
                continue
            }
        }

        bluePrint "[$idx] Busy(${pcpu}%) thread(${threadId}/${threadId0x}) stack of java process(${pid}) under user(${user}):"

        if [ -n "$mix_native_frames" ]; then
            local sed_script="/--------------- $threadId ---------------/,/^---------------/ {
                /--------------- $threadId ---------------/b # skip first seperator line
                /^---------------/d # delete second seperator line
                p
            }"
        elif [ -n "$force" ]; then
            local sed_script="/^Thread ${threadId}:/,/^$/ {
                /^$/d; p # delete end seperator line
            }"
        else
            local sed_script="/ nid=${threadId0x} /,/^$/ {
                /^$/d; p # delete end seperator line
            }"
        fi
        {
            sed "$sed_script" -n ${jstackFile}
            echo
        } | tee ${append_file:+-a "$append_file"} ${store_dir:+-a "${store_file_prefix}$PROG"}
    done
}

################################################################################
# Main
################################################################################

main() {
    local i
    # if update_count <= 0, infinite loop till user interrupted (eg: CTRL+C)
    for (( i = 0; update_count <= 0 || i < update_count; ++i )); do
        (( i > 0 )) && sleep "$update_delay"

        [ -n "$append_file" -o -n "$store_dir" ] && headInfo | tee ${append_file:+-a "$append_file"} ${store_dir:+-a "${store_file_prefix}$PROG"} > /dev/null
        (( update_count != 1 )) && headInfo

        if $use_ps; then
            findBusyJavaThreadsByPs
			 
        else
            findBusyJavaThreadsByTop
        fi | printStackOfThreads
		if [ -n "${pid}" ]; then
		   redPrint "jstat 列说明"
                   cat <<EOF
                  E（Eden区,新生代）
                  O(老年代)
                  FGC（Full GC）的次数
                  FGCT（Full GC Time）的累计时间                  

EOF
            ##时间间隔2s,查询次数10次
		   jstat -gcutil $pid 2000 10
		   redPrint "classname 类型说明"
		   cat <<EOF
           [C is a char[]
           [S is a short[]
           [I is a int[]
           [B is a byte[]
           [[I is a int[][]
EOF
		   jmap -histo $pid
		   fi
    done
}

main