github地址:

Arthas

English version goes here.

Arthas 是Alibaba開源的Java診斷工具，深受開發者喜愛。

當你遇到以下類似問題而束手無策時，Arthas可以幫助你解決：

1. 這個類從哪個 jar 包載入的？為什麼會報各種類相關的 Exception？
2. 我改的程式碼為什麼沒有執行到？難道是我沒 commit？分支搞錯了？
3. 遇到問題無法在線上 debug，難道只能通過加日誌再重新發布嗎？
4. 線上遇到某個使用者的資料處理有問題，但線上同樣無法 debug，線下無法重現！
5. 是否有一個全域性視角來檢視系統的執行狀況？
6. 有什麼辦法可以監控到JVM的實時執行狀態？

Arthas採用命令列互動模式，同時提供豐富的 Tab 自動補全功能，進一步方便進行問題的定位和診斷。

快速開始

Linux/Unix/Mac

安裝Arthas:

curl -L https://alibaba.github.io/arthas/install.sh | sh

啟動Arthas:

./as.sh

Windows

1. 點選 這裡 下載最新的Arthas zip包
2. 解壓縮zip包.
3. 進入bin目錄
4. 執行以下命令 as.bat $PID

文件

社群正在進行英文版本的翻譯工作，如果您有興趣請在 這裡留言。

案例展示

Dashboard

Thread

一目瞭然的瞭解系統的狀態，哪些執行緒比較佔cpu？他們到底在做什麼？

$ thread -n 3
"as-command-execute-daemon" Id=29 cpuUsage=75% RUNNABLE
    at sun.management.ThreadImpl.dumpThreads0(Native Method)
    at sun.management.ThreadImpl.getThreadInfo(ThreadImpl.java:440)
    at com.taobao.arthas.core.command.monitor200.ThreadCommand$1.action(ThreadCommand.java:58)
    at com.taobao.arthas.core.command.handler.AbstractCommandHandler.execute(AbstractCommandHandler.java:238)
    at com.taobao.arthas.core.command.handler.DefaultCommandHandler.handleCommand(DefaultCommandHandler.java:67)
    at com.taobao.arthas.core.server.ArthasServer$4.run(ArthasServer.java:276)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:745)

    Number of locked synchronizers = 1
    - 
 
[email protected]

"as-session-expire-daemon" Id=25 cpuUsage=24% TIMED_WAITING
    at java.lang.Thread.sleep(Native Method)
    at com.taobao.arthas.core.server.DefaultSessionManager$2.run(DefaultSessionManager.java:85)

"Reference Handler" Id=2 cpuUsage=0% WAITING on [email protected]
    at java.lang.Object.wait(Native Method)
    -  waiting on [email protected]
    at java.lang.Object.wait(Object.java:503)
    at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:133)

jad

對類進行反編譯:

$ jad javax.servlet.Servlet

ClassLoader:
[email protected]
  [email protected]
    [email protected]

Location:
/Users/xxx/work/test/lib/servlet-api.jar

/*
 * Decompiled with CFR 0_122.
 */
package javax.servlet;

import java.io.IOException;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

public interface Servlet {
    public void init(ServletConfig var1) throws ServletException;

    public ServletConfig getServletConfig();

    public void service(ServletRequest var1, ServletResponse var2) throws ServletException, IOException;

    public String getServletInfo();

    public void destroy();
}

sc

查詢JVM中已經載入的類

$ sc -d org.springframework.web.context.support.XmlWebApplicationContext
 class-info        org.springframework.web.context.support.XmlWebApplicationContext
 code-source       /Users/xxx/work/test/WEB-INF/lib/spring-web-3.2.11.RELEASE.jar
 name              org.springframework.web.context.support.XmlWebApplicationContext
 isInterface       false
 isAnnotation      false
 isEnum            false
 isAnonymousClass  false
 isArray           false
 isLocalClass      false
 isMemberClass     false
 isPrimitive       false
 isSynthetic       false
 simple-name       XmlWebApplicationContext
 modifier          public
 annotation
 interfaces
 super-class       +-org.springframework.web.context.support.AbstractRefreshableWebApplicationContext
                     +-org.springframework.context.support.AbstractRefreshableConfigApplicationContext
                       +-org.springframework.context.support.AbstractRefreshableApplicationContext
                         +-org.springframework.context.support.AbstractApplicationContext
                           +-org.springframework.core.io.DefaultResourceLoader
                             +-java.lang.Object
 class-loader      +-org.apache.catalina.loader.ParallelWebappClassLoader
                     [email protected]
                       [email protected]
                         [email protected]
 classLoaderHash   25131501

stack

檢視方法 test.arthas.TestStack#doGet 的呼叫堆疊：

$ stack test.arthas.TestStack doGet
Press Ctrl+C to abort.
Affect(class-cnt:1 , method-cnt:1) cost in 286 ms.
ts=2018-09-18 10:11:45;thread_name=http-bio-8080-exec-10;id=d9;is_daemon=true;priority=5;[email protected]01
    @test.arthas.TestStack.doGet()
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:624)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
        at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:110)
        ...
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:451)
        at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1121)
        at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)
        at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.lang.Thread.run(Thread.java:745)

Trace

觀察方法執行的時候那個子呼叫比較慢:

Watch

觀察方法 test.arthas.TestWatch#doGet 執行的入參，僅當方法丟擲異常時才輸出。

$ watch test.arthas.TestWatch doGet {params[0], throwExp} -e
Press Ctrl+C to abort.
Affect(class-cnt:1 , method-cnt:1) cost in 65 ms.
ts=2018-09-18 10:26:28;[email protected][
    @RequestFacade[[email protected]],
    @NullPointerException[java.lang.NullPointerException],
]

Classloader

瞭解當前系統中有多少類載入器，以及每個載入器載入的類數量，幫助您判斷是否有類載入器洩露。

$ classloader
 name                                                  numberOfInstances  loadedCountTotal
 BootstrapClassLoader                                  1                  3346
 com.taobao.arthas.agent.ArthasClassloader             1                  1262
 java.net.URLClassLoader                               2                  1033
 org.apache.catalina.loader.ParallelWebappClassLoader  1                  628
 sun.reflect.DelegatingClassLoader                     166                166
 sun.misc.Launcher$AppClassLoader                      1                  31
 com.alibaba.fastjson.util.ASMClassLoader              6                  15
 sun.misc.Launcher$ExtClassLoader                      1                  7
 org.jvnet.hk2.internal.DelegatingClassLoader          2                  2
 sun.reflect.misc.MethodUtil                           1                  1

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