S3 upload throws Concurrent read operations are not allowed! when uploading 32mb file

[tmageebtr]

Description

Using code similar to the S3 upload example, chunked_stream_reader.dart throws 'Concurrent read operations are not allowed!'

This is caused by 2 processes trying to read from the file stream at the same time.

Potential issue identified tracing through s3_upload_task.dart:

_startNextUploadPartsBatch starts up to 4 chunk readers sequentially. Each of these starts a synchronous process to send the chunk to S3. As the uploads finish they trigger another call to _startNextUploadPartsBatch which waits for the first batch to finish. If more than 1 upload process finishes before the first batch finishes we can end up with 2 new _startNextUploadPartsBatch both waiting for the first batch to finish. When that first batch does finish, the 2 new _startNextUploadPartsBatch both start trying to read the file stream resulting in concurrent read attempts.

Categories

• Analytics
• API (REST)
• API (GraphQL)
• Auth
• Authenticator
• DataStore
• Notifications (Push)
• Storage

Steps to Reproduce

Using example S3 upload code, upload file greater than 20Mb (4 chunks * 5Mb max chunk)

Screenshots

No response

Platforms

• iOS
• Android
• Web
• macOS
• Windows
• Linux

Flutter Version

3.24.4

Amplify Flutter Version

2.5.0

Deployment Method

Amplify Gen 2

Schema

No response

[Equartey]

Hi @tmageebtr, thanks for taking the time to open this issue. We will investigate this issue and provide an update when we can.

[ekjotmultani]

Hi @tmageebtr, a fix for this has been released in Storage 2.5.1! Thanks again for reporting this issue. Let us know if you have any more questions.

[github-actions]

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