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Block Canary——Android Performance Monitor

A transparent ui-block detection library for Android, app only needs one-line-code to setup.

Chinese README

Android Performance Monitor Maven Central

A transparent ui-block detection library for Android, app only needs one-line-code to setup.

The naming is to pay respect to the great library LeakCanary, ui-related codes are modified from leakcanary’s ui part.

Getting started

You may choose how to assemble them as you like.

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dependencies {
// most often used way, enable notification to notify block event
compile 'com.github.markzhai:blockcanary-android:1.5.0'

// this way you only enable BlockCanary in debug package
// debugCompile 'com.github.markzhai:blockcanary-android:1.5.0'
// releaseCompile 'com.github.markzhai:blockcanary-no-op:1.5.0'
}

As this library uses getMainLooper().setMessageLogging(), please check if you set it in your app (related issue https://github.com/moduth/blockcanary/issues/27)

Usage

Maximum log count is set to 500, you can rewrite it in your app int.xml.

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<integer name="block_canary_max_stored_count">1000</integer>

Monitor app’s label and icon can be configured by placing a block_canary_icon drawable in your xhdpi drawable directory and in strings.xml:

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<string name="block_canary_display_activity_label">Blocks</string>

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public class DemoApplication extends Application {
@Override
public void onCreate() {
// ...
// Do it on main process
BlockCanary.install(this, new AppBlockCanaryContext()).start();
}
}

Implement your application BlockCanaryContext context (strongly recommend you to check all these configs):

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public class AppBlockCanaryContext extends BlockCanaryContext {

/**
* Implement in your project.
*
* @return Qualifier which can specify this installation, like version + flavor.
*/
public String provideQualifier() {
return "unknown";
}

/**
* Implement in your project.
*
* @return user id
*/
public String provideUid() {
return "uid";
}

/**
* Network type
*
* @return {@link String} like 2G, 3G, 4G, wifi, etc.
*/
public String provideNetworkType() {
return "unknown";
}

/**
* Config monitor duration, after this time BlockCanary will stop, use
* with {@code BlockCanary}'s isMonitorDurationEnd
*
* @return monitor last duration (in hour)
*/
public int provideMonitorDuration() {
return -1;
}

/**
* Config block threshold (in millis), dispatch over this duration is regarded as a BLOCK. You may set it
* from performance of device.
*
* @return threshold in mills
*/
public int provideBlockThreshold() {
return 1000;
}

/**
* Thread stack dump interval, use when block happens, BlockCanary will dump on main thread
* stack according to current sample cycle.
* <p>
* Because the implementation mechanism of Looper, real dump interval would be longer than
* the period specified here (especially when cpu is busier).
* </p>
*
* @return dump interval (in millis)
*/
public int provideDumpInterval() {
return provideBlockThreshold();
}

/**
* Path to save log, like "/blockcanary/", will save to sdcard if can.
*
* @return path of log files
*/
public String providePath() {
return "/blockcanary/";
}

/**
* If need notification to notice block.
*
* @return true if need, else if not need.
*/
public boolean displayNotification() {
return true;
}

/**
* Implement in your project, bundle files into a zip file.
*
* @param src files before compress
* @param dest files compressed
* @return true if compression is successful
*/
public boolean zip(File[] src, File dest) {
return false;
}

/**
* Implement in your project, bundled log files.
*
* @param zippedFile zipped file
*/
public void upload(File zippedFile) {
throw new UnsupportedOperationException();
}


/**
* Packages that developer concern, by default it uses process name,
* put high priority one in pre-order.
*
* @return null if simply concern only package with process name.
*/
public List<String> concernPackages() {
return null;
}

/**
* Filter stack without any in concern package, used with @{code concernPackages}.
*
* @return true if filter, false it not.
*/
public boolean filterNonConcernStack() {
return false;
}

/**
* Provide white list, entry in white list will not be shown in ui list.
*
* @return return null if you don't need white-list filter.
*/
public List<String> provideWhiteList() {
LinkedList<String> whiteList = new LinkedList<>();
whiteList.add("org.chromium");
return whiteList;
}

/**
* Whether to delete files whose stack is in white list, used with white-list.
*
* @return true if delete, false it not.
*/
public boolean deleteFilesInWhiteList() {
return true;
}

/**
* Block interceptor, developer may provide their own actions.
*/
public void onBlock(Context context, BlockInfo blockInfo) {

}
}

How does it work?

Blog in Chinese: BlockCanary.

Principle flow picture:

flow

Screenshot


Contributors

This library is initially created by markzhai, and maintained under the organization moduth with nimengbo and zzz40500.

Special thanks to android-cjj, Mr.Bao, chiahaolu to contribute.

原理

熟悉Message/Looper/Handler系列的同学们一定知道Looper.java中这么一段:

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private static Looper sMainLooper;  // guarded by Looper.class

...

/**
* Initialize the current thread as a looper, marking it as an
* application's main looper. The main looper for your application
* is created by the Android environment, so you should never need
* to call this function yourself. See also: {@link #prepare()}
*/
public static void prepareMainLooper() {
prepare(false);
synchronized (Looper.class) {
if (sMainLooper != null) {
throw new IllegalStateException("The main Looper has already been prepared.");
}
sMainLooper = myLooper();
}
}

/** Returns the application's main looper, which lives in the main thread of the application.
*/
public static Looper getMainLooper() {
synchronized (Looper.class) {
return sMainLooper;
}
}

是的,就是这个Printer - mLogging,它在每个message处理的前后被调用,而如果主线程卡住了,不就是在dispatchMessage里卡住了吗?

核心流程图:

该组件利用了主线程的消息队列处理机制,通过

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Looper.getMainLooper().setMessageLogging(mainLooperPrinter);

并在mainLooperPrinter中判断start和end,来获取主线程dispatch该message的开始和结束时间,并判定该时间超过阈值(如2000毫秒)为主线程卡慢发生,并dump出各种信息,提供开发者分析性能瓶颈。

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@Override
public void println(String x) {
if (!mStartedPrinting) {
mStartTimeMillis = System.currentTimeMillis();
mStartThreadTimeMillis = SystemClock.currentThreadTimeMillis();
mStartedPrinting = true;
} else {
final long endTime = System.currentTimeMillis();
mStartedPrinting = false;
if (isBlock(endTime)) {
notifyBlockEvent(endTime);
}
}
}

private boolean isBlock(long endTime) {
return endTime - mStartTimeMillis > mBlockThresholdMillis;
}

说到此处,想到是不是可以用mainLooperPrinter来做更多事情呢?既然主线程都在这里,那只要parse出app包名的第一行,每次打印出来,是不是就不需要打点也能记录出用户操作路径? 再者,比如想做onClick到页面创建后的耗时统计,是不是也能用这个原理呢? 之后可以试试看这个思路(目前存在问题是获取线程堆栈是定时3秒取一次的,很可能一些比较快的方法操作一下子完成了没法在stacktrace里面反映出来)。

总结

BlockCanary作为一个Android组件,目前还有局限性,因为其在一个完整的监控系统中只是一个生产者,还需要对应的消费者去分析日志,比如归类排序,以便看出哪些卡慢更有修复价值,需要优先处理;又比如需要过滤机型,有些奇葩机型的问题造成的卡慢,到底要不要去修复是要斟酌的。扯远一点的话,像是埋点除了统计外,完全还能用来做链路监控,比如一个完整的流程是A -> B -> D -> E, 但是某个时间节点突然A -> B -> D后没有到达E,这时候监控平台就可以发出预警,让开发人员及时定位。很多监控方案都需要C/S两端的配合。

Reference

[1]AndroidPerformanceMonitor
[2]BlockCanary — 轻松找出Android App界面卡顿元凶

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