Azure-cli: `az storage blob delete-batch` - `--if-unmodified-since` not working

[ElvenSpellmaker]

...
DATE="$(date -ud "10 years ago" '+%Y-%m-%dT%H:%MZ')"
echo "$DATE"
...
    az storage blob delete-batch \
        --account-name "$NAME" \
        --account-key "$KEY" \
        --source "$CONTAINER" \
        --if-unmodified-since "$DATE" \
        --dryrun
...

I have some blobs modified in 2017, and I've tried 10 years ago (2008-04-13T16:06Z) and 10 years (2028-04-13T16:06Z) and both produce the same output:

delete action: from foo
    pattern None
  container foo
      total 67
 operations
  - FILE1
  - ...
...

No matter the date, I can't seem to get it to change its output 🤔

---

Environment summary

• python2
• pip2 install 'azure-cli==2.0.31' (also affects 2.0.28)

[troydai]

Please try the timestamp in the format of "2018-04-13T16:00:00Z" including the second.

[ElvenSpellmaker]

I had the seconds to start with, but it didn't make any difference, the docs (and other issues here) show without and so I changed it to remove the second.

[troydai]

Ok. @williexu, please take a look.

[troydai]

Ok. I see what's going on. The --dryrun parameter doesn't take the --if-unmodified-since into consideration. It was designed to help ensure the blob query string works.

Sorry for the confusion. This is indeed a bug at least indicate the documentation is misleading. Thanks for reporting this issue.

[williexu]

We have another issue about the same subject:
https://github.com/Azure/azure-cli/issues/5575

[ElvenSpellmaker]

@troydai That isn't a dryrun then? It's effectively just listing the contents of the container which is rather pointless (isn't it?) as you already can do that with something like:

az storage blob list --container $CONTAINER --account-name $NAME --account-key $KEY --query '[].name' -o tsv

I really need to confirm before I delete that I have the correct date range to delete when writing scripts and as it currently stands the delete-batch is far less useful without being able to dryrun.

As shown in #5575, it'd need server-side support, but it seems something that should exist?

[troydai]

You're right, @ElvenSpellmaker. It is not supported by the service, so the client has to try our best. I will bring this to the service team. We don't want to mislead the customer. The last thing we want to happen is the CLI indicate a file will not be deleted while deleted by the service during the real operation. The logic today is conservative enough to avoid this.

The main function of the --dryrun here is to test out your listing pattern in the command. The documentation / help is not sufficient enough to point this out, and we will update that part.