tusd: Azure storage does not support concatenation

Technical Knowledge of User I’m new to using tusd and the tus-js-client, so I’ll be happy if anybody can point out any problems in my setup for testing.

Describe the bug While running tusd with an Azure Storage backend, I found that the transfer would always fail on the last HTTP POST with a missing or invalid Upload-Length header. This only occurs when parallel upload (connections) are set to at least 2.

• Tested with the demo client included in tus-js-client and a nodejs client using tus-js-client.

Snippet of tusd logs during the end of a transfer:

[tusd] 2022/10/31 04:54:05.053405 event="ResponseOutgoing" status="201" method="POST" path="" requestId="" body="" 
[tusd] 2022/10/31 04:54:05.063695 event="RequestIncoming" method="PATCH" path="14ef5595737703227cbbe4c006cc7920" requestId="" 
[tusd] 2022/10/31 04:54:05.064181 event="RequestIncoming" method="PATCH" path="9d5eb446624ade5a25d719f07865fdd8" requestId="" 
[tusd] 2022/10/31 04:54:05.105852 event="ChunkWriteStart" id="9d5eb446624ade5a25d719f07865fdd8" maxSize="57738292" offset="0" 
[tusd] 2022/10/31 04:54:05.107953 event="ChunkWriteStart" id="14ef5595737703227cbbe4c006cc7920" maxSize="57738292" offset="0" 
[tusd] 2022/10/31 04:54:13.957541 event="ChunkWriteComplete" id="14ef5595737703227cbbe4c006cc7920" bytesWritten="57738292" 
[tusd] 2022/10/31 04:54:13.976012 event="ResponseOutgoing" status="204" method="PATCH" path="14ef5595737703227cbbe4c006cc7920" requestId="" body="" 
[tusd] 2022/10/31 04:54:13.976043 event="UploadFinished" id="14ef5595737703227cbbe4c006cc7920" size="57738292" 
[tusd] 2022/10/31 04:54:17.708767 event="ChunkWriteComplete" id="9d5eb446624ade5a25d719f07865fdd8" bytesWritten="57738292" 
[tusd] 2022/10/31 04:54:17.740995 event="ResponseOutgoing" status="204" method="PATCH" path="9d5eb446624ade5a25d719f07865fdd8" requestId="" body="" 
[tusd] 2022/10/31 04:54:17.741020 event="UploadFinished" id="9d5eb446624ade5a25d719f07865fdd8" size="57738292" 
[tusd] 2022/10/31 04:54:17.742362 event="RequestIncoming" method="POST" path="" requestId="" 
[tusd] 2022/10/31 04:54:17.742385 event="ResponseOutgoing" status="400" method="POST" path="" requestId="" body="ERR_INVALID_UPLOAD_LENGTH: missing or invalid Upload-Length header

Client side NodeJS using tus-js-client

0 115476584 0.00%
0 115476584 0.00%
65536 115476584 0.06%
131072 115476584 0.11%
31260672 115476584 27.07%
63569920 115476584 55.05%
90113076 115476584 78.04%
115476584 115476584 100.00%
Failed because: Error: tus: unexpected response while creating upload, originated from request (method: POST, url: http://127.0.0.1:47280/files/, response code: 400, response text: ERR_INVALID_UPLOAD_LENGTH: missing or invalid Upload-Length header
, request id: n/a)

To Reproduce Steps to reproduce the behavior:

1. Start up tusd server with Azure backend storage.
   podman run -p 47280:47280 -v /tmp/host/tus:/srv/ --env AZURE_STORAGE_ACCOUNT=<storage account name> --env AZURE_STORAGE_KEY=<azure storage key> docker.io/tusproject/tusd:v1.10.0 -port=47280 -azure-blob-access-tier=hot -azure-object-prefix=tus-prefix -azure-storage=tus-file-container -azure-endpoint=https://<storage account name>.blob.core.windows.net
2. Run the client demo or a nodejs client, set the parallel upload to 2.
3. Upload a file.
4. Watch the last POST message fail, and the file fail to combine - even though all the parts has been successfully sent.

Expected behavior I expect parallel uploads to work.

Setup details Please provide following details, if applicable to your situation:

• Operating System: Linux (Ubuntu 22.04 LTS) and the docker image OS is running for tus
• Used tusd version: Tried both tusd:v1.10.0 and tusd:2.0.0rc17
• Used tusd data storage: Azure Storage
• Used tusd configuration: -port=47280 -azure-blob-access-tier=hot -azure-object-prefix=tus-prefix -azure-storage=tus-file-container -azure-endpoint=https://<storage account name>.blob.core.windows.net
• Used tus client library: tus-js-client using nodejs and the tus-js-client demo

NodeJS client code

const fs = require('fs');
const tus = require("tus-js-client");

const path = "file.txt"
const file = fs.createReadStream(path)

const upload = new tus.Upload(file, {
  endpoint: 'http://127.0.0.1:47280/files/',
  parallelUploads: 2,

  // Callback for errors which cannot be fixed using retries
  onError: function(error) {
    console.log("Failed because: " + error)
  },
  
  // Callback for reporting upload progress
  onProgress: function(bytesUploaded, bytesTotal) {
    const percentage = (bytesUploaded / bytesTotal * 100).toFixed(2)
    console.log(bytesUploaded, bytesTotal, percentage + "%")
  },
  
  // Callback for once the upload is completed
  onSuccess: function() {
    console.log("Download %s from %s", upload.file.name, upload.url)
  }
});

// Check if there are any previous uploads to continue.
upload.findPreviousUploads()
  .then((previousUploads) => {

    // Found previous uploads so we select the first one. 
    if (previousUploads.length) {
      upload.resumeFromPreviousUpload(previousUploads[0])
    }

    // Start the upload
    upload.start()
})