Reason for failure in MultipartObjectAssembler OCI object storage - oracle-cloud-infrastructure

Question

I'm using MultipartObjectAssembler to upload data from a Database to OCI object storage.
Is there a way to know the reason for failure when using multipart upload?
When I try to commit assembler I'm getting IllegalStateException with the message "One or more parts were have not completed upload successfully".
I would like to know why any part got failed? I couldn't find a way to get this information from SDK.
try {
assembler.addPart(new ByteArrayInputStream(part, 0, length),
length,
null);
assembler.commit();
} catch (Exception e) {
assembler.abort();
throw new RuntimeException(e.getMessage());
}
Edit: I need to get an Exception thrown by a failed part and propagate the error message.

Answer 1

Is there a reason you are not using the UploadManager? It should do everything for you, including adding parts and committing. Here's an end-to-end example: https://github.com/oracle/oci-java-sdk/blob/master/bmc-examples/src/main/java/UploadObjectExample.java
If, for some reason, you cannot use UploadManager, please take a look at its source code nonetheless, since it demonstrates the intended usage of MultipartObjectAssembler: https://github.com/oracle/oci-java-sdk/blob/master/bmc-objectstorage/bmc-objectstorage-extensions/src/main/java/com/oracle/bmc/objectstorage/transfer/UploadManager.java#L175-L249
You create the MultipartObjectAssembler:
MultipartObjectAssembler assembler =
createAssembler(request, uploadRequest, executorServiceToUse);
You create a new request. This gives you back a MultipartManifest, which will later let you check if parts failed.
manifest =
assembler.newRequest(
request.getContentType(),
request.getContentLanguage(),
request.getContentEncoding(),
request.getOpcMeta());
Then you add all the parts:
assembler.addPart(
ProgressTrackingInputStreamFactory.create(
chunk, progressTrackerFactory.getProgressTracker()),
chunk.length(),
null);
Then you commit. This is where your code currently throws. I suspect not all parts have been added.
CommitMultipartUploadResponse response = assembler.commit();
If something goes wrong, check MultipartManifest.listCompletedParts(), MultipartManifest.listFailedParts(), and MultipartManifest.listInProgressParts(). The manifest should tell you what parts failed. Unfortunately not why; for that, you can enable ERROR level logging for com.oracle.bmc.objectstorage.transfer (for the class com.oracle.bmc.objectstorage.transfer.internal.MultipartTransferManager in particular).
If I have misunderstood something, please let me know. In that case, a larger, more complete code snippet would help me debug. Thanks!