Waiting for dependencies

This examples shows how to extend the .NET Aspire application model to enable waiting for dependencies to be available before starting the application. It uses ASP.NET Core's health checks API to determine if specific resources are available after they are considered running.

var builder = DistributedApplication.CreateBuilder(args);

var db = builder.AddSqlServer("sql")
    .WithHealthCheck()
    .AddDatabase("db");

var rabbit = builder.AddRabbitMQ("rabbit")
                    .WithHealthCheck();

var console = builder.AddProject<Projects.ConsoleApp1>("console");

builder.AddProject<Projects.WebApplication1>("api")
    .WithExternalHttpEndpoints()
    .WithReference(db)
    .WithReference(rabbit)
    // Wait for the database and rabbitmq to be healthy before starting the api
    .WaitFor(db)
    .WaitFor(rabbit)
    // Wait for the console application to run to completion
    .WaitForCompletion(console);

builder.Build().Run();

The above example shows the usage. WaitFor is an extension method that stores a reference to the dependency and waits for it to be healthy before starting a specific resource. In the above case, the api project will wait for the db and rabbit dependencies to be healthy before starting.