Microservices

Dependency Injection in a Microservice

The Beamable Unity SDK uses IDependencyBuilder and IDependencyProvider to manage dependencies. Beamable Microservices use the same structures to manage their dependencies as well. The same concepts from the SDK apply in the Microservices, but some minor details change.

Life Cycle

When a Microservice starts, there is one main IDependencyBuilder . In order to initialize and connect to Beamable, the IDependencyBuilder creates a main IDependencyProvider. However, every request sent to a Microservice will get a unique IDependencyProvider. The main scope is forked and modified with the RequestContext information for the request. When the request terminates, the child scope is disposed.

Scoped vs Singleton

In a Microservice, a service registered as a singleton will be the only instance of that service between all requests. It can be used to store a limited amount of state between service requests.

🚧

Do not store critical state in memory

Remember that a Microservice may be running multiple instances when deployed. This means that you should not assume that a singleton's class variables are stable across all requests. They are only stable for requests sent to the given instance of the Microservice.

A scoped service will be re-instantiated for each request.

Service Registration

In order to add or modify service registrations, the Microservice class must have a static method that is tagged with the ConfigureServices attribute, and accepts an IServiceBuilder instance. The IServiceBuilder has a .Builder accessor that exposes a IDependencyBuilder.

C#

[ConfigureServices]
public static void Configure(IServiceBuilder builder)
{
  builder.Builder.AddScoped<ExampleService>();
}

Service Resolution

In a Microservice, you can access the request's IDependencyProvider through the internal class members of the Microservice class.

C#

[ClientCallable]
public void Test()
{
    var service = Provider.GetService<ExampleService>();
}