Update Azure Postgres code

[eerhardt]

The EntityFramwork code to talk to Azure Postgres is incorrect. It needs to be different depending on the version of EF being used.

Fix #2769

[roji]

Looks great, thanks.

Just to make sure - the switch from UsePeriodicPasswordProvider to UsePasswordProvider is in principle good, but can you confirm whether credentials.GetTokenAsync() internally caches the token? If not, that's a new token for each physical connection, which might be a bit much. The lambdas passed to UsePasswordProvider could implement caching to mitigate that if we think that's important.

[eerhardt]

but can you confirm whether credentials.GetTokenAsync() internally caches the token?

I don't believe it caches itself. At least I haven't seen any code that does this.

The lambdas passed to UsePasswordProvider could implement caching to mitigate that if we think that's important.

This would be too much code / implementation for sample/doc code. Instead it would be a great thing for a specific package to deal with Entra ID + Npgsql.

[roji]

This would be too much code / implementation for sample/doc code. Instead it would be a great thing for a npgsql/npgsql#5992.

I guess I agree... It's unfortunate for our basic sample to show something inefficient, but hopefully we'll have a package soon. FWIW the performance of opening a new physical connection (as opposed to getting a pooled one) isn't that critical.

[davidfowl]

@roji are you working on a package that can switch between normal Postgres and azure? That’s what we need to do to take away all of the pain here and what aspire intends to do if there’s no other alternative

[roji]

@davidfowl I agree - this is something that I raised internally with the Azure folk themselves; I believe there should be an Azure.Npgsql package, and that they should ideally own it. I'll forward you the email thread in case you're interested etc.

[roji]

(oh I see you already got looped in)