What is the @DefaultExecutor annotation referred to in the Async Data Fetching section of the docs?

[arichardson175]

Specifically here: https://netflix.github.io/dgs/data-loaders/#using-spring-features-such-as-securitycontextholder-inside-a-completablefuture

For context, I've run into the mentioned issue where I'm trying to access some thread local data (specifically the RequestAttributes bound to the thread processing the request) inside of an async data fetcher. I found this section in the docs, but can't find any other references to @DefaultExecutor anywhere. Is this something custom?

[berngp]

@arichardson175 , you are right. The @DefaultExecutor annotation is an internal construct and we should remove it from the docs. You will have to build an executor that is able to set, and re-set, the RequestAttributes available in the context of each thread. This is not a unique problem of the RequestAttributes but any context dependent construct, such as the SecurityContext as well.

Spring Security

In Spring Security you will have to leverage the DelegatingSecurityContextAsyncTaskExecutor.

@Bean 
public DelegatingSecurityContextAsyncTaskExecutor taskExecutor(ThreadPoolTaskExecutor delegate) { 
    return new DelegatingSecurityContextAsyncTaskExecutor(delegate); 
}

Spring Web MVC

class RequestAttributesAsyncTaskExecutor implements AsyncTaskExecutor {
	private final AsyncTaskExecutor asyncTaskExecutor;
	public RequestAttributesAsyncTaskExecutor(AsyncTaskExecutor asyncTaskExecutor) {
		this.asyncTaskExecutor = asyncTaskExecutor;
	}

	@Override
	public void execute(Runnable task, long startTimeout) {
		asyncTaskExecutor.execute(wrap(task), startTimeout);
	}

	@Override
	@NonNull
	public Future<?> submit(@NonNull Runnable task) {
		return asyncTaskExecutor.submit(wrap(task));
	}
	
        @Override
	public <T> Future<T> submit(Callable<T> task) {
		return asyncTaskExecutor.submit(wrap(task));
	}

	@Override
	public void execute(Runnable task) {
		asyncTaskExecutor.execute(wrap(task));
	}

	private Runnable wrap(Runnable delegate) {
		Optional<RequestAttributes> optRequestAttributes = getRequestAttributes();
		return () -> {
			setRequestAttributes(optRequestAttributes);
			try {
				delegate.run();
			}
			finally {
				resetRequestAttributes(optRequestAttributes);
			}
		};
	}

	private <T> Callable<T> wrap(Callable<T> delegate) {
		Optional<RequestAttributes> optRequestAttributes = getRequestAttributes();
		return () -> {
			setRequestAttributes(optRequestAttributes);
			try {
				return delegate.call();
			}
			finally {
				resetRequestAttributes(optRequestAttributes);
			}
		};
	}

	private Optional<RequestAttributes> getRequestAttributes() {
		try {
			return Optional.ofNullable(RequestContextHolder.getRequestAttributes());
		}
		catch (Exception e) {
			logger.warn(
					"Unable to fetch the RequestAttributes based on the RequestContextHolder.getRequestAttributes method.",
					e);
			return Optional.empty();
		}
	}

	private void setRequestAttributes(final Optional<RequestAttributes> optionalRequestAttributes) {
		try {
			optionalRequestAttributes.ifPresent(RequestContextHolder::setRequestAttributes);
		}
		catch (Exception e) {
			logger.warn("Unable to set the RequestAttributes.", e);
		}
	}

	private void resetRequestAttributes(final Optional<RequestAttributes> optionalRequestAttributes) {
		try {
			optionalRequestAttributes.ifPresent(requestAttributes -> RequestContextHolder.resetRequestAttributes());
		}
		catch (Exception e) {
			logger.warn("Unable to reset the RequestAttributes.", e);
		}
	}
}

[arichardson175]

Thanks for clarifying @berngp. I spent some more time working with this and ended up implementing a solution with DgsCustomContextBuilderWithRequest, which appears to work nicely.

Do you know if there's any reason to be wary of retrieving request information that way?

[berngp]

Not at all, that would be the preferred way.

[arichardson175]

Great. Thank you very much for your help @berngp!