[QUERY]What happens when continuation tokens become invalid?

[JohanKlijn]

Library name and version

Azure.Storage.Blobs 12.19.1

Query/Question

There was a question "Do continuation tokens expire?" The answer was: "continuation tokens do not expire at a specific time, but may become invalid over time as blobs are added or removed from the container in question."

Question is, what means invalid? For example what happens when blobs are added/removed?

• Will it throw an exception?
• Will it ignore blobs which are added?
• Blobs are ordered lexicographically by name when calling GetBlobsAsync. So let's say I have the blobs A B C E F G (so no D yet) and in the last call to GetBlobsAsync I retrieved E. What will happen when a blob D is added? Will I just get F with the next call to GetBlobsAsync or ....?

Environment

No response

[github-actions]

Thanks for the feedback! We are routing this to the appropriate team for follow-up. cc @xgithubtriage.

[amnguye]

Will it throw an exception?

If you hand an invalid / expired continuation token, the service will send back an error, and the SDK will throw a RequestFailedException

Will it ignore blobs which are added?

It is not guaranteed that blobs added to the container, will be listed

Blobs are ordered lexicographically by name when calling GetBlobsAsync. So let's say I have the blobs A B C E F G (so no D yet) and in the last call to GetBlobsAsync I retrieved E. What will happen when a blob D is added? Will I just get F with the next call to GetBlobsAsync or ....?

It is not guaranteed that the blob D will be listed in the next GetBlobsAsync call.

To guarantee valid listing behavior, start from the beginning of the GetBlobsAsync call.

[JohanKlijn]

Hi @amnguye,  

Can you be more specific on how this is working? In what kind of scenario's will the continuation token invalid/expired? In our case we need to process millions of blobs, and we need to make sure all the blobs are processed. As you can imagine when building an enterprise application we need to know what the behavior is of the continuation token? It should be documented somewhere because any application using this continuation token needs to be able to handle the situation when the token becomes invalid. The application can't just start from the beginning again, because probably the token becomes invalid again, right?

Regards,
Johan