Updating a blob validating assessments for students with disabilities
This was really the crux of the question, but the gentlemen asking the question had thrown the additional aspect of the CDN into the mix.The CDN is a way to geo-distribute your files across the globe .
To avoid this issue make sure to use the ETag values in the response to make sure it hasn’t changed since you started to get the file.
Meaning, the file isn’t updated until the update is fully complete and the BLOB Storage will continue to serve the previous version until the new version is committed.
We should never see any sort of corruption due to a file update being in progress.
At an Azure Boot Camp this last week I was asked how the Azure CDN (Content Delivery Network) handled file updates if a file was being updated at the same time one of the CDN nodes requests the file.
I wasn’t sure how the system would react, so I sent off an email to the get the answer. If you are familiar with BLOB storage and the CDN just skip to the fourth paragraph.
Search for updating a blob:
You can read more about ETags in http on wiki-pedia.