Update health check to ensure blob containers created at right time

[RussKie]

Resolves #9139
Resolves #9145

I removed ResourceReadyEvent handler, and moved blob container creation logic into the BlobStorage health check. This way, once we connected to the storage emulator and have the service client, we can ensure the requested blob containers are created.

Kudos to @mitchdenny for giving me some ideas.

[davidfowl]

Hmm, we had this debate when @sebastienros did the database creation and I thought we decided to use the ResourceReady event (which runs after health checks).

[eerhardt]

Hmm, we had this debate when @sebastienros did the database creation and I thought we decided to use the ResourceReady event (which runs after health checks).

For databases, do we:

aspire/src/Aspire.Hosting.SqlServer/SqlServerBuilderExtensions.cs

Lines 58 to 77 in 88ff939

	builder.Eventing.Subscribe<ResourceReadyEvent>(sqlServer, async (@event, ct) =>
	{
	if (connectionString is null)
	{
	throw new DistributedApplicationException($"ResourceReadyEvent was published for the '{sqlServer.Name}' resource but the connection string was null.");
	}
	using var sqlConnection = new SqlConnection(connectionString);
	await sqlConnection.OpenAsync(ct).ConfigureAwait(false);
	if (sqlConnection.State != System.Data.ConnectionState.Open)
	{
	throw new InvalidOperationException($"Could not open connection to '{sqlServer.Name}'");
	}
	foreach (var sqlDatabase in sqlServer.DatabaseResources)
	{
	await CreateDatabaseAsync(sqlConnection, sqlDatabase, @event.Services, ct).ConfigureAwait(false);
	}
	});

aspire/src/Aspire.Hosting.PostgreSQL/PostgresBuilderExtensions.cs

Lines 66 to 90 in 88ff939

	builder.Eventing.Subscribe<ResourceReadyEvent>(postgresServer, async (@event, ct) =>
	{
	if (connectionString is null)
	{
	throw new DistributedApplicationException($"ResourceReadyEvent was published for the '{postgresServer.Name}' resource but the connection string was null.");
	}
	// Non-database scoped connection string
	using var npgsqlConnection = new NpgsqlConnection(connectionString + ";Database=postgres;");
	await npgsqlConnection.OpenAsync(ct).ConfigureAwait(false);
	if (npgsqlConnection.State != System.Data.ConnectionState.Open)
	{
	throw new InvalidOperationException($"Could not open connection to '{postgresServer.Name}'");
	}
	foreach (var name in postgresServer.Databases.Keys)
	{
	if (builder.Resources.FirstOrDefault(n => string.Equals(n.Name, name, StringComparisons.ResourceName)) is PostgresDatabaseResource postgreDatabase)
	{
	await CreateDatabaseAsync(npgsqlConnection, postgreDatabase, @event.Services, ct).ConfigureAwait(false);
	}
	}
	});

In general, I dislike using health checks to mutate state. They should just be used to check health, not make something "healthy".

[RussKie]

I am not super fond of this result, but I couldn't find a way to add a healthcheck for individual blob containers.
I originally added blob container creation within ResourceReadyEvent, however, it appears this makes the test flaky - there's a race condition, and the client may attempt to access blob container before those get created.
If I add a check alongside the blob storage, then ResourceReadyEvent never get fired (since no containers yet exist). I couldn't add a healthcheck within the even - the service collection at this point is already locked.

Any suggestions?