Unable to pause/resume file upload.

[puneesh]

I am following samples mentioned here to pause and resume file upload to S3 bucket.

Issue I am facing is that the moment upload.pause() is called java.util.concurrent.CancellationException: null is thrown and Transfer failed. is printed in log.

So, if I catch exception - I am able to persist upload information using resumableFileUpload.serializeToFile(path) but resume is not happening when this line executes FileUpload resumedUpload = transferManager.resumeUploadFile(persistedResumableFileUpload). What am I missing here? please advise.

I am using 2.20.0 version of s3-transfer-manager, aws-crt, aws-crt-client under software.amazon.awssdk

[debora-ito]

When resume is called, is there any error in the logs?
Can you provide a self-contained code sample I can use to reproduce?

[robertbio]

I have a similar use case where CancellationException: null is thrown in the transfer listener when I try to pause after a network interruption during an upload/download. The uploaded file has to be big enough; once it starts uploading, just remove the internet connection and wait for the code get to fileUpload.pause(). To that matter, changing from wifi to cable or stopping a VPN connections also freezes the progress. One issue is the exception on pause; another is the resilience to switching connections. This is a desktop client app.

	void uploadExample(S3TransferManager transferManager, String bucket, String key, Path bigLocalFilePath) throws InterruptedException, ExecutionException {
		// Upload a file to S3 usint the TransferManager.
		FileUpload fileUpload = transferManager.uploadFile(u -> u.source(bigLocalFilePath)
				.putObjectRequest(p -> p.bucket(bucket)
						.key(key))
				.addTransferListener(CustomLoggingTransferListener.create(10)));

		long lastCheckTransferedBytes = 0L;
		while (true) {
			try {
				// I had some problems where fileUpload.completionFuture().join() would get stuck if there was a connection switch,
				// so now I check progress every 5 minutes or pause and resume (and additional logic can go here).
				fileUpload.completionFuture()
						.get(5, TimeUnit.SECONDS); // .get(5, TimeUnit.MINUTES); // set seconds to fail faster.
				return; // done downloading.
			} catch (TimeoutException e) {
				long newMeasurement = fileUpload.progress().snapshot().transferredBytes();
				log.debug("Timeout: New measurement: {} - Old: {}", newMeasurement, lastCheckTransferedBytes);
				if (newMeasurement <= lastCheckTransferedBytes) {
					// no progress
					ResumableFileUpload pause = fileUpload.pause();
					// resilience logic... pause and set continue.
				}
				lastCheckTransferedBytes = newMeasurement;
			}
		}
	}

Edit: I corrected the code. I only see the cancellation exception in the CustomLoggingTransferListener that get the method transferFailed triggered and prints the context.exception(), but the pause content is ok and can be used for resuming the upload.

[debora-ito]

@puneesh Thank you for the code sample, I'll try to reproduce.
Can you share the full stacktrace with the error you are seeing?

[puneesh]

@debora-ito please see if attached screenshot is helpful.

[puneesh]

@debora-ito please advise.

[puneesh]

@debora-ito please advise, if you were able to replicate this issue.