How to access the value of a parameter

[vandenbergjp]

After upgrading to 9.4 I get a bunch of the following warnings:

Warning CS0618 : 'ParameterResource.Value' is obsolete: 'Use GetValueAsync for async access or pass the ParameterResource directly to methods that accept it (e.g., environment variables).'

What is the recommended way to work with this in the following examples:

var mydb =
    mySqlServer
       .AddDatabase("mydb")
       .WithCreationScript(script.Replace("<MigratorPasswordPlaceHolder>", migratorPasswordParameter.Resource.Value));
	   
var migrator =
    builder
       .AddProject<Migrator>("Migrator")
       .WithEnvironment(context =>
        {
            context.EnvironmentVariables.Add("ConnectionStrings__Migrator", $"Data Source=127.0.0.1,{mySqlServer.Resource.PrimaryEndpoint.Port};Initial Catalog={mydb.Resource.DatabaseName};User ID=migrator_user;Password={migratorPasswordParameter.Resource.Value};TrustServerCertificate=true");
        });

In the example code I get the warning everywhere i try to use migratorPasswordParameter.Resource.Value.

In this use-case i have a creation script that creates multiple logins with different permissions on the database. And later on, I try to setup a connection string that uses one of those logins.

[davidfowl]

Required reading https://github.com/dotnet/aspire/blob/main/docs/specs/appmodel.md#values-and-references

For this one, there's no great alternative other than reading the configuration value directly. Though I'm surprised you need the password in the SQL script (why do you need that?).

cc @sebastienros (we need a callback version of WithCreationScript);

var mydb =
    mySqlServer
       .AddDatabase("mydb")
       .WithCreationScript(script.Replace("<MigratorPasswordPlaceHolder>", migratorPasswordParameter.Resource.Value));

For this one, you can use a reference expression to build up the connection string:

var expr = ReferenceExpression.Create($"Data Source=127.0.0.1,{mySqlServer.Resource.PrimaryEndpoint.Property(EndpointProperty.Port)};Initial Catalog={mydb.Resource.DatabaseName};User ID=migrator_user;Password={migratorPasswordParameter};TrustServerCertificate=true");

var migrator =
    builder
       .AddProject<Migrator>("Migrator")
       .WithEnvironment(context =>
        {
            context.EnvironmentVariables.Add("ConnectionStrings__Migrator", expr);
        });

The reason .Value is deprecated is because the value might not be set and can be set at runtime using the new parameter value dialog https://learn.microsoft.com/en-us/dotnet/aspire/whats-new/dotnet-aspire-9.4#-interactive-parameter-prompting-during-run-mode

[vandenbergjp]

Thanks for the quick response. I updated the question with the use-case. I have a creation script that (among other things) creates different logins with different database permissions. I don't want to put the password directly in the creation script. So, I have a creation script where I replace some placeholders with the actual passwords.

[davidfowl]

Filed #10876.

[vandenbergjp]

I tried the solution with the ReferenceExpression and it seems to works. Thanks!

It would be great if the issue with the CreationScript can be solved. Thanks for creating issue #10876.

And i didn't know about the existence of https://github.com/dotnet/aspire/blob/main/docs/specs/appmodel.md#values-and-references. I will definitely give it a read.