Java Code Examples for org.apache.commons.lang3.exception.ExceptionUtils#getStackFrames()

private static MultiStatus createMultiStatus(Throwable t) {
	final List<Status> childStatuses = new ArrayList<>();
	final String[] stacks = ExceptionUtils.getStackFrames(t);
	for (int i = 0; i < stacks.length; i++) {
		// Filter the first stack, otherwise the Exception is listed twice in the UI.
		if (i > 0) {
			childStatuses.add(new Status(IStatus.ERROR, Activator.PLUGIN_ID, stacks[i].replace("\t", "   ")));
		}
	}
	final MultiStatus ms = new MultiStatus(Activator.PLUGIN_ID, IStatus.ERROR,
			childStatuses.toArray(new Status[] {}), t.toString(), t);
	return ms;
}
 

/**
 * Converts an internal exception thrown by Conductor into an StatusException
 * that uses modern "Status" metadata for GRPC.
 *
 * Note that this is trickier than it ought to be because the GRPC APIs have
 * not been upgraded yet. Here's a quick breakdown of how this works in practice:
 *
 * Reporting a "status" result back to a client with GRPC is pretty straightforward.
 * GRPC implementations simply serialize the status into several HTTP/2 trailer headers that
 * are sent back to the client before shutting down the HTTP/2 stream.
 *
 * - 'grpc-status', which is a string representation of a {@link com.google.rpc.Code}
 * - 'grpc-message', which is the description of the returned status
 * - 'grpc-status-details-bin' (optional), which is an arbitrary payload with a serialized
 *  ProtoBuf object, containing an accurate description of the error in case the status is not
 *  successful.
 *
 *  By convention, Google provides a default set of ProtoBuf messages for the most common
 *  error cases. Here, we'll be using {@link DebugInfo}, as we're reporting an internal
 *  Java exception which we couldn't properly handle.
 *
 *  Now, how do we go about sending all those headers _and_ the {@link DebugInfo} payload
 *  using the Java GRPC API?
 *
 *  The only way we can return an error with the Java API is by passing an instance of
 *  {@link io.grpc.StatusException} or {@link io.grpc.StatusRuntimeException} to
 *  {@link StreamObserver#onError(Throwable)}. The easiest way to create either of these
 *  exceptions is by using the {@link Status} class and one of its predefined code
 *  identifiers (in this case, {@link Status#INTERNAL} because we're reporting an internal
 *  exception). The {@link Status} class has setters to set its most relevant attributes,
 *  namely those that will be automatically serialized into the 'grpc-status' and 'grpc-message'
 *  trailers in the response. There is, however, no setter to pass an arbitrary ProtoBuf message
 *  to be serialized into a `grpc-status-details-bin` trailer. This feature exists in the other
 *  language implementations but it hasn't been brought to Java yet.
 *
 *  Fortunately, {@link Status#asException(Metadata)} exists, allowing us to pass any amount
 *  of arbitrary trailers before we close the response. So we're using this API to manually
 *  craft the 'grpc-status-detail-bin' trailer, in the same way that the GRPC server implementations
 *  for Go and C++ craft and serialize the header. This will allow us to access the metadata
 *  cleanly from Go and C++ clients by using the 'details' method which _has_ been implemented
 *  in those two clients.
 *
 * @param t The exception to convert
 * @return an instance of {@link StatusException} which will properly serialize all its
 * headers into the response.
 */
private StatusException throwableToStatusException(Throwable t) {
    String[] frames = ExceptionUtils.getStackFrames(t);
    Metadata metadata = new Metadata();
    metadata.put(STATUS_DETAILS_KEY,
            DebugInfo.newBuilder()
                    .addAllStackEntries(Arrays.asList(frames))
                    .setDetail(ExceptionUtils.getMessage(t))
                    .build()
    );

    return Status.INTERNAL
            .withDescription(t.getMessage())
            .withCause(t)
            .asException(metadata);
}