Microservice Routing

Dependencies

Before you can configure Beamable Standalone Microservices, you need to complete the Getting-Started Guide. That means having Dotnet 8 installed, and getting the Beam CLI.

You can confirm you have everything installed checking the versions of the tools.

dotnet --version
beam version # beam --version also works.

In order to configure a Microservice, you also need to have a local .beamable workspace with a Beamable Standalone Microservice. As a reminder, you can create one quickly using the commands below.

beam init MyProject
cd MyProject
dotnet beam project new service HelloWorld

Microservice Routing

Beamable Microservices use a privileged web socket to communicate with Beamable's existing APIs and services. There is a custom Beamable application level protocol, Thorium, that allows a Microservice to receive HTTPS traffic sent to https://api.beamable.com. However, for the Microservice to receive the traffic, the HTTP request needs to meet the following requirements,

1. The uri of the HTTP request must have a path that maps to the desired Microservice.
2. The HTTP request must have an X-DE-SCOPE header, and
3. Optionally, the HTTP request should have a X-BEAM-SERVICE-ROUTING-KEY header that carries a map of service routing keys, and
4. Optionally, the HTTP request should have an Authorization header that carries a Bearer Token.

Path Routing

The uri of the HTTP request destined for a Microservice must follow a strict format. The format is given by the code snippet below.

var uri = 'https://' + host + '/basic/' + cid + '.' + pid + '.' + localPrefix + 'micro_' + serviceName + '/' + method;

The variables are described in the following table.

When the host (api.beamable.com) receives an HTTP request with the following uri format, the request will be deconstructed into the variable components, and the contents of the HTTP request will be forwarded to your Microservice via the Thorium web socket protocol. The Microservice receives the request, and uses the method component of the original request to invoke the right [Callable] method.

X-BEAM-SERVICE-ROUTING-KEY

When a Microservice is started locally, it may share the same name with a Microservice running in the Beamable cloud. When this happens, and your local development machine is generating traffic for the named service, the routing key defines which Microservice instance (the local or remote) receives the traffic.

A Microservice instance may optionally register a routing key, and if they do, then they will only receive traffic that includes the routing key in a custom X-BEAM-SERVICE-ROUTING-KEY header.

All microservice instances running on the Beamable cloud do not register any routing keys, so they receive traffic that does not include any X-BEAM-SERVICE-ROUTING-KEY value.

The format of the X-BEAM-SERVICE-ROUTING-KEY value should be a series of <service>:<routingKey> pairs, separated by commas. Here is an example of a routing key header value that routes two services,

serviceA:routingKeyA,serviceB:routingKeyB

X-DE-SCOPE Header

In addition to specifying the cid and pid in the uri of the HTTP request, those values must also be sent in a special HTTP header, X-DE-SCOPE. The value for this header should take the format,

var scope = cid + '.' + pid;

Authorization

Finally, while not required, it is important to send an HTTP authorization header in the form of a Bearer token. The bearer token should be a valid access token for a Beamable Player. These tokens can be fetched from the Portal, or you can use the following command to view the token information from a local beamable CLI project.

cat .beamable/temp/connection-auth.json

Beamable does not require that any access token be provided via an authorization header. However, if an authorization header is provided, then Beamable will decorate the request with account information before the request is forwarded to the Microservice. The Microservice itself may enforce the account details to have minimal access permissions. These constraints vary based on the type of [Callable] attribute you use.

The account information is accessible via the Context.UserId property when executing the [Callable] method.

Calling Microservice Code From Unity

📘

Use the Unity SDK

You should be using the Beamable SDK in your Unity projects that use Standalone Microservices. Otherwise, there will be many compile errors as the Beamable SDK is not available.

Microservices can automatically generate client code for the Unity game engine. First, a Unity project needs to be linked to the .beamable workspace. To do this, use the project add-unity-project command.

dotnet beam project add-unity-project <relative-path-to-unity-project>

The given path should be the relative path to the Unity project. If it isn't right, the CLI will offer an explorative search flow to identify a valid Unity project.

After the command has run, there will be a .beamable/linked-projects.json file. You can review it to double check your project has been added correctly.

MyProject % cat .beamable/linked-projects.json 
{
  "unityProjectsPaths": [
    "../UnityProject"
  ],
  "unrealProjectsPaths": []
}%  

When there is a linked project, anytime a Microservice builds, it will automatically generate client code for the Unity project to use. This can be accessed via the BeamContext.

public async Promise TalkToMicroservice(){
	var ctx = await BeamContext.Default.Instance;  
	var client = ctx.Microservices().HelloWorld();  
	var sum = await client.Add(1, 2);
}

The automatic client code generation can be disabled when a project builds by modifying the <GenerateClientCode> option. Learn more in the configuration guide.

Custom Clients

It is possible to use the project oapi command to generate an Open API document and then use open source tools to transpile the document into a client in some other programming language.

The following command will output the Open API document for the service into a file called doc.json.

beam project oapi --ids HelloWorld | jq '.data.openApi | fromjson' > doc.json

In fact, that command can baked into the Microservice's .csproj file with a custom build target. This requires that the <SolutionDir> property is set, which only happens when you run the project from the IDE. See the generate-props command to extend the <SolutionDir> property outside of IDE use cases.

<Target Name="Build Local OpenAPI File" AfterTargets="Build">  
    <Exec Command="$(BeamableTool) project oapi --ids HelloWorld | jq '.data.openApi | fromjson' > $(SolutionDir)local/doc.json"/>  
</Target>

Then, you can use the open source Open API Generator to build a local javascript client. This snippet uses docker to interact with the generator tool, but you can also use npm.

docker run --rm -v "${PWD}:/local" openapitools/openapi-generator-cli generate \
	-i /local/doc.json \
	-g javascript \
	--additional-properties=usePromises=true \
	-o /local/out/js

In this example, we need to use browserify to convert the generated client code into a valid browser script.

npm install -g browserify
browserify ./dist/index.js --standalone helloWorld > ../../app/bundle.js 

Then, a sample web page might use a similar script to interact with the Microservice.

<html>
    <body>
        <script src="bundle.js"></script>

        <script>
            var cid = 'cid';
            var pid = 'pid';
            var refreshToken = 'redacted';
            var serviceName = 'HelloWorld';

            var host = 'https://api.beamable.com/basic/' + cid + '.' + pid + '.' + 'micro_' + serviceName;
            var client = new helloWorld.ApiClient(host);
            client.authentications['scope'].apiKey = cid + '.' + pid;
            client.authentications['user'].accessToken = refreshToken
            
            var api = new helloWorld.UncategorizedApi(client);
            var args = new helloWorld.AddRequestArgs();
            args.a = 2;
            args.b = 3;

            var opts = {
                'addRequestArgs': args
            };
            api.addPost(opts).then(function(result) {
                console.log('got result', result)
            });

        </script>
    </body>
</html>```