使用AWS TransferManager上载时找不到堆栈跟踪

Question

I am using the TransferManager to upload some files on my server to S3 asynchronously. The problem is that it is failing for an unknown reason and I am not seeing any exceptions in the logs.

I see a comment in the documentation for seeing the exception when the transfer fails. The problem is that this requires blocking the thread.

// Or you can block the current thread and wait for your transfer to
// to complete. If the transfer fails, this method will throw an
// AmazonClientException or AmazonServiceException detailing the reason.
myUpload.waitForCompletion();

I've tried using the ProgressListener, but that seems to only notify me when the transfer fails. I don't see any exceptions thrown.

Is there a way to view these exceptions without blocking?

Answer 1

Once the ProgressListener notifies you that the upload is complete (or has failed), you can call waitForCompletion to get the result without blocking.

public class FailureListener extends SyncProgressListener {

    public static void bind(Upload upload) {
        upload.addProgressListener(new FailureListener(upload));
    }

    private final Upload upload;

    public FailureListener(Upload upload) {
        this.upload = upload;
    }

    @Override
    public void progressChanged(ProgressEvent progressEvent) {
        if (progressEvent.getEventType() == ProgressEventType.TRANSFER_FAILED_EVENT) {
            AmazonClientException e = getException();
            e.printStackTrace();
        }
    }

    private AmazonClientException getException() {
        try {
            // Won't actually "wait" since the transfer has already failed.
            return upload.waitForException();
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
            throw new Error("WTF?", e);
        }
    }
}