Delete obsolete files on deploy

[zbynek]

https://blobxfer.readthedocs.io/en/1.0.0/10-cli-usage/ says --delete is what's needed to get rid of obsolete files. I don't have any way to test this.

[hervelemeur]

Closes jenkins-infra/helpdesk#3360

[lemeurherve]

We might want to be sure of our backups before merging this in case something goes wrong.

[dduportal]

Thinking about it: if we want to rollback a deletion what would be the options ?

• backups as @hervelemeur mentioned
• the azure bucket history (if we can have such feature)
• Build reproduction (we checkout an old commit an rebuild it to get the files)

[zbynek]

We could also list all files that are in the storage right now (someone with access to Azure would have to help there), compare it with a list of files that are generated by a clean build of this repo and see if anything important would be deleted.

[lemeurherve]

Preparing a backup of the storage account and a list of its files.

[lemeurherve]

We could also list all files that are in the storage right now (someone with access to Azure would have to help there), compare it with a list of files that are generated by a clean build of this repo and see if anything important would be deleted.

@zbynek I've posted the corresponding list here, could you take a look at it please?
jenkins-infra/helpdesk#3360 (comment)

[zbynek]

@lemeurherve afaik the conclusion of the helpdesk ticket is that nothing important will disappear. Can we proceed with this?

[lemeurherve]

@zbynek sorry I wanted to do that this week but been busy on other tasks, I should have posted an update.

I'd like to be sure the backup restore works well before merging this PR, I'll keep you updated.

[lemeurherve]

@zbynek FYI: jenkins-infra/helpdesk#3360 (comment)