更新：最新版本的Intellij IDEA implements正是我正在寻找的。问题是如何在IDE之外实现这一点（所以我可以将异步堆栈跟踪转储到日志文件中），理想情况下不需要使用仪器代理。
自从我将应用程序从同步模型转换为异步模型后，我遇到调试失败的问题。
当我使用同步API时，我总是在异常堆栈跟踪中找到我的类，所以我知道从哪里开始查找是否出错。使用异步API，我得到的堆栈跟踪不会引用我的类，也不会指示哪个请求触发了失败。
我会给你一个具体的例子，但我对这类问题的一般解决方案感兴趣。
我使用Jersey发出HTTP请求：
new Client().target("http://test.com/").request().rx().get(JsonNode.class);
其中rx()表示请求应异步发生，直接返回CompletionStage<JsonNode>而不是JsonNode。如果此调用失败，我会得到此堆栈跟踪：
javax.ws.rs.ForbiddenException: HTTP 403 Authentication Failed
at org.glassfish.jersey.client.JerseyInvocation.convertToException(JerseyInvocation.java:1083)
at org.glassfish.jersey.client.JerseyInvocation.translate(JerseyInvocation.java:883)
at org.glassfish.jersey.client.JerseyInvocation.lambda$invoke$1(JerseyInvocation.java:767)
at org.glassfish.jersey.internal.Errors.process(Errors.java:316)
at org.glassfish.jersey.internal.Errors.process(Errors.java:298)
at org.glassfish.jersey.internal.Errors.process(Errors.java:229)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:414)
at org.glassfish.jersey.client.JerseyInvocation.invoke(JerseyInvocation.java:765)
at org.glassfish.jersey.client.JerseyInvocation$Builder.method(JerseyInvocation.java:456)
at org.glassfish.jersey.client.JerseyCompletionStageRxInvoker.lambda$method$1(JerseyCompletionStageRxInvoker.java:70)
at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1590)
注意：
因此，我无法将异常追溯到其来源。
如果你深入挖掘，你会发现Jersey is invoking：
CompletableFuture.supplyAsync(() -> getSyncInvoker().method(name, entity, responseType))
用于rx()次调用。因为供应商是由泽西岛建造的，所以没有参考用户代码。
I tried filing a bug report针对Jetty提出了一个无关的异步示例，后来由于安全原因被拒绝了。
相反，我一直在添加上下文信息如下：
makeHttpRequest().exceptionally(e ->
{
throw new RuntimeException(e);
});
意思是，我在代码中的每个HTTP请求之后手动添加exceptionally()。 Jersey抛出的任何异常都包含在引用我的代码的辅助异常中。生成的堆栈跟踪如下所示：
java.lang.RuntimeException: javax.ws.rs.ForbiddenException: HTTP 403 Authentication Failed
at my.user.code.Testcase.lambda$null$1(Testcase.java:25)
at java.util.concurrent.CompletableFuture.uniExceptionally(CompletableFuture.java:870)
... 6 common frames omitted
Caused by: javax.ws.rs.ForbiddenException: HTTP 403 Authentication Failed
at org.glassfish.jersey.client.JerseyInvocation.convertToException(JerseyInvocation.java:1083)
at org.glassfish.jersey.client.JerseyInvocation.translate(JerseyInvocation.java:883)
at org.glassfish.jersey.client.JerseyInvocation.lambda$invoke$1(JerseyInvocation.java:767)
at org.glassfish.jersey.internal.Errors.process(Errors.java:316)
at org.glassfish.jersey.internal.Errors.process(Errors.java:298)
at org.glassfish.jersey.internal.Errors.process(Errors.java:229)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:414)
at org.glassfish.jersey.client.JerseyInvocation.invoke(JerseyInvocation.java:765)
at org.glassfish.jersey.client.JerseyInvocation$Builder.method(JerseyInvocation.java:456)
at org.glassfish.jersey.client.JerseyCompletionStageRxInvoker.lambda$method$1(JerseyCompletionStageRxInvoker.java:70)
at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1590)
... 3 common frames omitted
我不喜欢这种方法，因为它容易出错并降低了代码的可读性。如果我错误地忽略了某些HTTP请求，我最终会得到一个模糊的堆栈跟踪，并花费大量时间跟踪它。
此外，如果我想在实用程序类后面隐藏这个技巧，那么我必须在CompletionStage之外实例化一个异常;否则，实用程序类将显示在堆栈跟踪而不是实际的调用站点中。在CompletionStage之外实例化异常非常昂贵，因为即使异步调用没有抛出任何异常，此代码也会运行。
是否有一种强大的，易于维护的方法来向异步调用添加上下文信息？
或者，是否有一种有效的方法可以在没有此上下文信息的情况下将堆栈跟踪追溯到其源？
答案 0 :(得分：1)
看到这个问题在近一个月内没有得到任何答案，我将发布迄今为止我发现的最佳解决方案：
<强> DebugCompletableFuture.java ：
/**
* A {@link CompletableFuture} that eases debugging.
*
* @param <T> the type of value returned by the future
*/
public final class DebugCompletableFuture<T> extends CompletableFuture<T>
{
private static RunMode RUN_MODE = RunMode.DEBUG;
private static final Set<String> CLASS_PREFIXES_TO_REMOVE = ImmutableSet.of(DebugCompletableFuture.class.getName(),
CompletableFuture.class.getName(), ThreadPoolExecutor.class.getName());
private static final Set<Class<? extends Throwable>> EXCEPTIONS_TO_UNWRAP = ImmutableSet.of(AsynchronousException.class,
CompletionException.class, ExecutionException.class);
private final CompletableFuture<T> delegate;
private final AsynchronousException asyncStacktrace;
/**
* @param delegate the stage to delegate to
* @throws NullPointerException if any of the arguments are null
*/
private DebugCompletableFuture(CompletableFuture<T> delegate)
{
requireThat("delegate", delegate).isNotNull();
this.delegate = delegate;
this.asyncStacktrace = new AsynchronousException();
delegate.whenComplete((value, exception) ->
{
if (exception == null)
{
super.complete(value);
return;
}
exception = Exceptions.unwrap(exception, EXCEPTIONS_TO_UNWRAP);
asyncStacktrace.initCause(exception);
filterStacktrace(asyncStacktrace, element ->
{
String className = element.getClassName();
for (String prefix : CLASS_PREFIXES_TO_REMOVE)
if (className.startsWith(prefix))
return true;
return false;
});
Set<String> newMethods = getMethodsInStacktrace(asyncStacktrace);
if (!newMethods.isEmpty())
{
Set<String> oldMethods = getMethodsInStacktrace(exception);
newMethods.removeAll(oldMethods);
if (!newMethods.isEmpty())
{
// The async stacktrace introduces something new
super.completeExceptionally(asyncStacktrace);
return;
}
}
super.completeExceptionally(exception);
});
}
/**
* @param exception an exception
* @return the methods referenced by the stacktrace
* @throws NullPointerException if {@code exception} is null
*/
private Set<String> getMethodsInStacktrace(Throwable exception)
{
requireThat("exception", exception).isNotNull();
Set<String> result = new HashSet<>();
for (StackTraceElement element : exception.getStackTrace())
result.add(element.getClassName() + "." + element.getMethodName());
for (Throwable suppressed : exception.getSuppressed())
result.addAll(getMethodsInStacktrace(suppressed));
return result;
}
/**
* @param <T2> the type returned by the delegate
* @param delegate the stage to delegate to
* @return if {@code RUN_MODE == DEBUG} returns an instance that wraps {@code delegate}; otherwise, returns {@code delegate}
* unchanged
* @throws NullPointerException if any of the arguments are null
*/
public static <T2> CompletableFuture<T2> wrap(CompletableFuture<T2> delegate)
{
if (RUN_MODE != RunMode.DEBUG)
return delegate;
return new DebugCompletableFuture<>(delegate);
}
/**
* Removes stack trace elements that match a filter. The exception and its descendants are processed recursively.
* <p>
* This method can be used to remove lines that hold little value for the end user (such as the implementation of utility functions).
*
* @param exception the exception to process
* @param elementFilter returns true if the current stack trace element should be removed
*/
private void filterStacktrace(Throwable exception, Predicate<StackTraceElement> elementFilter)
{
Throwable cause = exception.getCause();
if (cause != null)
filterStacktrace(cause, elementFilter);
for (Throwable suppressed : exception.getSuppressed())
filterStacktrace(suppressed, elementFilter);
StackTraceElement[] elements = exception.getStackTrace();
List<StackTraceElement> keep = new ArrayList<>(elements.length);
for (StackTraceElement element : elements)
{
if (!elementFilter.test(element))
keep.add(element);
}
exception.setStackTrace(keep.toArray(new StackTraceElement[0]));
}
@Override
public <U> CompletableFuture<U> thenApply(Function<? super T, ? extends U> fn)
{
return wrap(super.thenApply(fn));
}
@Override
public <U> CompletableFuture<U> thenApplyAsync(Function<? super T, ? extends U> fn)
{
return wrap(super.thenApplyAsync(fn));
}
@Override
public <U> CompletableFuture<U> thenApplyAsync(Function<? super T, ? extends U> fn, Executor executor)
{
return wrap(super.thenApplyAsync(fn, executor));
}
@Override
public CompletableFuture<Void> thenAccept(Consumer<? super T> action)
{
return wrap(super.thenAccept(action));
}
@Override
public CompletableFuture<Void> thenAcceptAsync(Consumer<? super T> action)
{
return wrap(super.thenAcceptAsync(action));
}
@Override
public CompletableFuture<Void> thenAcceptAsync(Consumer<? super T> action, Executor executor)
{
return wrap(super.thenAcceptAsync(action, executor));
}
@Override
public CompletableFuture<Void> thenRun(Runnable action)
{
return wrap(super.thenRun(action));
}
@Override
public CompletableFuture<Void> thenRunAsync(Runnable action)
{
return wrap(super.thenRunAsync(action));
}
@Override
public CompletableFuture<Void> thenRunAsync(Runnable action, Executor executor)
{
return wrap(super.thenRunAsync(action, executor));
}
@Override
public <U, V> CompletableFuture<V> thenCombine(CompletionStage<? extends U> other,
BiFunction<? super T, ? super U, ? extends V> fn)
{
return wrap(super.thenCombine(other, fn));
}
@Override
public <U, V> CompletableFuture<V> thenCombineAsync(CompletionStage<? extends U> other,
BiFunction<? super T, ? super U, ? extends V> fn)
{
return wrap(super.thenCombineAsync(other, fn));
}
@Override
public <U, V> CompletableFuture<V> thenCombineAsync(CompletionStage<? extends U> other,
BiFunction<? super T, ? super U, ? extends V> fn,
Executor executor)
{
return wrap(super.thenCombineAsync(other, fn, executor));
}
@Override
public <U> CompletableFuture<Void> thenAcceptBoth(CompletionStage<? extends U> other,
BiConsumer<? super T, ? super U> action)
{
return wrap(super.thenAcceptBoth(other, action));
}
@Override
public <U> CompletableFuture<Void> thenAcceptBothAsync(CompletionStage<? extends U> other,
BiConsumer<? super T, ? super U> action)
{
return wrap(super.thenAcceptBothAsync(other, action));
}
@Override
public <U> CompletableFuture<Void> thenAcceptBothAsync(CompletionStage<? extends U> other,
BiConsumer<? super T, ? super U> action,
Executor executor)
{
return wrap(super.thenAcceptBothAsync(other, action, executor));
}
@Override
public CompletableFuture<Void> runAfterBoth(CompletionStage<?> other, Runnable action)
{
return wrap(super.runAfterBoth(other, action));
}
@Override
public CompletableFuture<Void> runAfterBothAsync(CompletionStage<?> other, Runnable action)
{
return wrap(super.runAfterBothAsync(other, action));
}
@Override
public CompletableFuture<Void> runAfterBothAsync(CompletionStage<?> other, Runnable action, Executor executor)
{
return wrap(super.runAfterBothAsync(other, action, executor));
}
@Override
public <U> CompletableFuture<U> applyToEither(CompletionStage<? extends T> other, Function<? super T, U> fn)
{
return wrap(super.applyToEither(other, fn));
}
@Override
public <U> CompletableFuture<U> applyToEitherAsync(CompletionStage<? extends T> other, Function<? super T, U> fn)
{
return wrap(super.applyToEitherAsync(other, fn));
}
@Override
public <U> CompletableFuture<U> applyToEitherAsync(CompletionStage<? extends T> other, Function<? super T, U> fn,
Executor executor)
{
return wrap(super.applyToEitherAsync(other, fn, executor));
}
@Override
public CompletableFuture<Void> acceptEither(CompletionStage<? extends T> other, Consumer<? super T> action)
{
return wrap(super.acceptEither(other, action));
}
@Override
public CompletableFuture<Void> acceptEitherAsync(CompletionStage<? extends T> other, Consumer<? super T> action)
{
return wrap(super.acceptEitherAsync(other, action));
}
@Override
public CompletableFuture<Void> acceptEitherAsync(CompletionStage<? extends T> other, Consumer<? super T> action,
Executor executor)
{
return wrap(super.acceptEitherAsync(other, action, executor));
}
@Override
public CompletableFuture<Void> runAfterEither(CompletionStage<?> other, Runnable action)
{
return wrap(super.runAfterEither(other, action));
}
@Override
public CompletableFuture<Void> runAfterEitherAsync(CompletionStage<?> other, Runnable action)
{
return wrap(super.runAfterEitherAsync(other, action));
}
@Override
public CompletableFuture<Void> runAfterEitherAsync(CompletionStage<?> other, Runnable action, Executor executor)
{
return wrap(super.runAfterEitherAsync(other, action, executor));
}
@Override
public <U> CompletableFuture<U> thenCompose(Function<? super T, ? extends CompletionStage<U>> fn)
{
return wrap(super.thenCompose(fn));
}
@Override
public <U> CompletableFuture<U> thenComposeAsync(Function<? super T, ? extends CompletionStage<U>> fn)
{
return wrap(super.thenComposeAsync(fn));
}
@Override
public <U> CompletableFuture<U> thenComposeAsync(Function<? super T, ? extends CompletionStage<U>> fn,
Executor executor)
{
return wrap(super.thenComposeAsync(fn, executor));
}
@Override
public CompletableFuture<T> exceptionally(Function<Throwable, ? extends T> fn)
{
return wrap(super.exceptionally(fn));
}
@Override
public CompletableFuture<T> whenComplete(BiConsumer<? super T, ? super Throwable> action)
{
return wrap(super.whenComplete(action));
}
@Override
public CompletableFuture<T> whenCompleteAsync(BiConsumer<? super T, ? super Throwable> action)
{
return wrap(super.whenCompleteAsync(action));
}
@Override
public CompletableFuture<T> whenCompleteAsync(BiConsumer<? super T, ? super Throwable> action,
Executor executor)
{
return wrap(super.whenCompleteAsync(action, executor));
}
@Override
public <U> CompletableFuture<U> handle(BiFunction<? super T, Throwable, ? extends U> fn)
{
return wrap(super.handle(fn));
}
@Override
public <U> CompletableFuture<U> handleAsync(BiFunction<? super T, Throwable, ? extends U> fn)
{
return wrap(super.handleAsync(fn));
}
@Override
public <U> CompletableFuture<U> handleAsync(BiFunction<? super T, Throwable, ? extends U> fn,
Executor executor)
{
return wrap(super.handleAsync(fn, executor));
}
@Override
public boolean complete(T value)
{
return delegate.complete(value);
}
@Override
public boolean completeExceptionally(Throwable ex)
{
return delegate.completeExceptionally(ex);
}
}
<强> RunMode.java ：
/**
* Operational modes.
*/
public enum RunMode
{
/**
* Optimized for debugging problems (extra runtime checks, logging of the program state).
*/
DEBUG,
/**
* Optimized for maximum performance.
*/
RELEASE
}
<强> AsynchronousException.java
/**
* Thrown when an asynchronous operation fails. The stacktrace indicates who triggered the operation.
*/
public final class AsynchronousException extends RuntimeException
{
private static final long serialVersionUID = 0L;
public AsynchronousException()
{
}
}
用法：
DebugCompletableFuture.wrap(CompletableFuture.supplyAsync(this::expensiveOperation));
上行：您将获得相对干净的异步堆栈跟踪。
下行：每次创建未来时构建一个新的AsynchronousException都非常昂贵。具体来说，如果您生成大量未来，这会在堆上产生大量垃圾，并且GC开销变得明显。
我仍然希望有人会提出一种表现更好的方法。
答案 1 :(得分：0)
这可能是由于JVM update所发现的栈耗尽了发出相同的日志，因此它开始忽略了它。
该解决方案使用-XX:-OmitStackTraceInFastThrow标志来防止JVM优化内置异常堆栈跟踪。