How to pass Connection String to another container via Environment Variable?

[grish-st]

Hey guys. I have resources with connection strings (MSSQL, Redis, Kafka, etc.), and a dependency application that I run via Docker. I need to pass these connection strings to this application. But the problem is that the connection strings use "localhost" as the host, which doesn't work in other containers. So how can I get the "internal connection string" let's say? Thanks.

var redis = builder.AddRedis("redis");

var app = builder.AddContainer("app", "app-image", "latest")
    .WithEnvironment("Redis_ConnectionString", redis.Resource.ConnectionStringExpression); // localhost:6379 !!!

[davidfowl]

What version of aspire are you using? This was fixed in 9.5, it'll prefer the container name for container to container references https://learn.microsoft.com/en-us/dotnet/aspire/whats-new/dotnet-aspire-9.5#context-based-endpoint-resolution

[grish-st]

I fixed this, thank you.
Also I have a one more question. I need to pass connection string of resource A to resource B, and the connection string of resource B to resource A. I couldn't find a solution to this problem, so I wrote this hack:

var resourceABuilder = builder.AddResourceA();
var resourceBBuilder = builder.AddResourceB(); 

builder.Eventing.Subscribe<BeforeResourceStartedEvent>(
    resourceABuilder.Resource,
    async (_, ct) =>
    {
        var connectionString = await resourceB.ConnectionStringExpression.GetValueAsync(ct);
        resourceABuilder.WithEnvironment("ResourceB__ConnectionString", connectionString);
    }
);

builder.Eventing.Subscribe<BeforeResourceStartedEvent>(
    resourceBBuilder.Resource,
    async (_, ct) =>
    {
        var connectionString = await resourceA.ConnectionStringExpression.GetValueAsync(ct);
        resourceBBuilder.WithEnvironment("ResourceA__ConnectionString", connectionString);
    }
);

It's working, but I think it's not a good solution. Do you know any other ways to achieve this? Thank you.

[davidfowl]

I fixed this, thank you.

Fixed it how?

[grish-st]

I saw localhosts in the debugger, the correct hosts were passed to the containers. It's a bit confusing, but it's probably not a problem. And also I changed IPV4Host to Host in some places.

P.S. What about my next question? Do you have any idea?

[davidfowl]

var resourceABuilder = builder.AddResourceA();
var resourceBBuilder = builder.AddResourceB(); 

resourceBBuilder.WithEnvironment("ResourceA__ConnectionString",resourceABuilder); 
resourceABuilder.WithEnvironment("ResourceB__ConnectionString", resourceBBuilder);

[grish-st]

Thank you)