Sending file to blob only works when function is called in while loop

Question

I have the Azure blob sample code which I'm trying to modify. However, the uploadFile function only works when it is in the while loop in a switch case. If I take it out of the loop, it creates the container but fails to upload the file.

I've tried taking it out and calling the function from different places in the code, but none of them work.

uploadFile function:

 static void uploadFile(BlockBlobURL blob, File sourceFile) throws IOException {

        AsynchronousFileChannel fileChannel = AsynchronousFileChannel.open(sourceFile.toPath());

        // Uploading a file to the blobURL using the high-level methods available in TransferManager class
        // Alternatively call the PutBlob/PutBlock low-level methods from BlockBlobURL type
        TransferManager.uploadFileToBlockBlob(fileChannel, blob, 8*1024*1024, null, null)
                .subscribe(response-> {
                    System.out.println("Completed upload request.");
                    TimeUnit.SECONDS.sleep(5);
                    System.out.println(response.response().statusCode());
                });


    }

Relevant part of main

            // Listening for commands from the console
            //THIS IS THE PART THAT ONLY MAKES THE CONTAINER
            /*
            System.out.println("Uploading the sample file into the container: " + containerURL );
            uploadFile(blobURL, sampleFile);
            System.out.println("File Uploaded");
            */
            //TRYING TO CALL FUNCTION FROM OUTSIDE WHILE, BUT IT ONLY WORKS HERE
            System.out.println("Enter a command");
            System.out.println("(P)utBlob | (L)istBlobs | (G)etBlob");
            BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
            while (true) {
                System.out.println("# Enter a command : ");
                String input = reader.readLine();
                switch(input){
                    case "P":
                        System.out.println("Uploading the sample file into the container: " + containerURL );
                        uploadFile(blobURL, sampleFile);
                        break;

The uploadFile called outside of the while loop creates the container but doesn't actually upload a file to the blob, while uploadFile from in the while loop and switch case does

Answer 1

This won't upload the blob because the upload process has not finished and the main process has finished. So I just add a Thread.sleep() to the main process. And reminder don't set the value too short or it still fails. In my test I set it to 2000 millisecond.

public static void main(String[] args) throws java.lang.Exception{


        ContainerURL containerURL;

        // Creating a sample file to use in the sample
        File sampleFile = null;

        try {
            sampleFile = File.createTempFile("downloadedFile", ".txt");

            // Retrieve the credentials and initialize SharedKeyCredentials
            String accountName = "xxxxxx";
            String accountKey = "xxxxxxx";

            // Create a ServiceURL to call the Blob service. We will also use this to construct the ContainerURL
            SharedKeyCredentials creds = new SharedKeyCredentials(accountName, accountKey);
            // We are using a default pipeline here, you can learn more about it at https://github.com/Azure/azure-storage-java/wiki/Azure-Storage-Java-V10-Overview
            final ServiceURL serviceURL = new ServiceURL(new URL("https://" + accountName + ".blob.core.windows.net"), StorageURL.createPipeline(creds, new PipelineOptions()));

            // Let's create a container using a blocking call to Azure Storage
            // If container exists, we'll catch and continue
            containerURL = serviceURL.createContainerURL("quickstart");

            try {
                ContainerCreateResponse response = containerURL.create(null, null, null).blockingGet();
                System.out.println("Container Create Response was " + response.statusCode());
            } catch (RestException e){
                if (e instanceof RestException && ((RestException)e).response().statusCode() != 409) {
                    throw e;
                } else {
                    System.out.println("quickstart container already exists, resuming...");
                }
            }

            // Create a BlockBlobURL to run operations on Blobs
            final BlockBlobURL blobURL = containerURL.createBlockBlobURL("SampleBlob.txt");

            System.out.println("Uploading the sample file into the container: " + containerURL );
            AsynchronousFileChannel fileChannel = AsynchronousFileChannel.open(sampleFile.toPath());


            // Uploading a file to the blobURL using the high-level methods available in TransferManager class
            // Alternatively call the PutBlob/PutBlock low-level methods from BlockBlobURL type
            TransferManager.uploadFileToBlockBlob(fileChannel, blobURL, 8*1024*1024, null, null)
                    .subscribe(response-> {
                        System.out.println("Completed upload request.");
                        System.out.println(response.response().statusCode());
                    });

            Thread.sleep(2000);

        } catch (InvalidKeyException e) {
            System.out.println("Invalid Storage account name/key provided");
        } catch (MalformedURLException e) {
            System.out.println("Invalid URI provided");
        } catch (RestException e){
            System.out.println("Service error returned: " + e.response().statusCode() );
        } catch (IOException e) {
            e.printStackTrace();
            System.exit(-1);
        }
    }