Actor

Dapr Actor example

The Actor example shows how to create a virtual actor (DemoActor) and invoke its methods on the client application.

Prerequisites

• .NET 6+ installed
• Dapr CLI
• Initialized Dapr environment
• Dapr .NET SDK

Projects in sample

• The interface project (\IDemoActor) contains the interface definition for the actor. The interface defines the actor contract that is shared by the actor implementation and the clients calling the actor. Because client projects may depend on it, it typically makes sense to define it in an assembly that is separate from the actor implementation.

• The actor service project (\DemoActor) implements ASP.Net Core web service that is going to host the actor. It contains the implementation of the actor. An actor implementation is a class that derives from the base type Actor and implements the interfaces defined in the corresponding interfaces project. An actor class must also implement a constructor that accepts an ActorService instance and an ActorId and passes them to the base Actor class.

• The actor client project (\ActorClient) contains the implementation of the actor client which calls DemoActor's methods defined in IDemoActor's Interfaces.

Running the example

To run the actor service locally run this command in DemoActor directory:

 dapr run --dapr-http-port 3500 --app-id demo_actor --app-port 5010 dotnet run

The DemoActor service will listen on port 5010 for HTTP.

Make client calls

The ActorClient project shows how to make client calls for actor using Remoting which provides a strongly typed invocation experience. Run the client project from ActorClient directory as:

 dotnet run

Note: If you started the actor service with dapr port other than 3500, then set the environment variable DAPR_HTTP_PORT to the value of --dapr-http-port specified while starting the actor service before running the client in terminal.

On Windows: set DAPR_HTTP_PORT=<port>
On Linux, MacOS: export DAPR_HTTP_PORT=<port>

Invoke Actor method without Remoting over Http

You can invoke Actor methods without remoting (directly over http), if the Actor method accepts at-most one argument. Actor runtime will deserialize the incoming request body from client and use it as method argument to invoke the actor method. When making non-remoting calls Actor method arguments and return types are serialized, deserialized as JSON.

Save Data Following curl call will save data for actor id "abc" (below calls on MacOs, Linux & Windows are exactly the same except for escaping quotes on Windows for curl)

On Linux, MacOS:

curl -X POST http://127.0.0.1:3500/v1.0/actors/DemoActor/abc/method/SaveData -d '{ "PropertyA": "ValueA", "PropertyB": "ValueB" }'

On Windows:

curl -X POST http://127.0.0.1:3500/v1.0/actors/DemoActor/abc/method/SaveData -d "{ \"PropertyA\": \"ValueA\", \"PropertyB\": \"ValueB\" }"

Get Data Following curl call will get data for actor id "abc" (below calls on MacOs, Linux & Windows are exactly the same except for escaping quotes on Windows for curl)

On Linux, MacOS:

curl -X POST http://127.0.0.1:3500/v1.0/actors/DemoActor/abc/method/GetData

On Windows:

curl -X POST http://127.0.0.1:3500/v1.0/actors/DemoActor/abc/method/GetData

Build and push Docker image

You can build the docker image of DemoActor service by running the following commands in the DemoActor project directory:

dotnet publish --os linux --arch x64 /t:PublishContainer -p ContainerImageTags='"latest"' --self-contained

The build produce and image with tag demo-actor:latest and load it in the local registry. Now the image can be pushed to your remote Docker registry by running the following commands:

# Replace <your-docker-registry> with your Docker registry
docker tag demo-actor:latest <your-docker-registry>/demo-actor:latest

# Push the image to your Docker registry
docker push <your-docker-registry>/demo-actor:latest

Deploy the Actor service to Kubernetes

Prerequisites

• A Kubernetes cluster with kubectl configured to access it.
• Dapr v1.14+ installed on the Kubernetes cluster. Follow the instructions here.
• A Docker registry where you pushed the DemoActor image.

Deploy the Actor service

For quick deployment you can install dapr in dev mode using the following command:

dapr init -k --dev

To deploy the DemoActor service to Kubernetes, you can use the provided Kubernetes manifest file demo-actor.yaml in the DemoActor project directory. Before applying the manifest file, replace the image name in the manifest file with the image name you pushed to your Docker registry.

Part to update in demo-actor.yaml:

image: <your-docker-registry>/demoactor:latest

To install the application in default namespace, run the following command:

kubectl apply -f demo-actor.yaml

This will deploy the DemoActor service to Kubernetes. You can check the status of the deployment by running:

kubectl get pods -n default --watch

The manifest create 2 services:

• demoactor service: The service that hosts the DemoActor actor.
• demoactor-dapr service: The service that hosts the Dapr sidecar for the DemoActor actor.

Make client calls to the deployed Actor service

To make client calls to the deployed DemoActor service, you can use the ActorClient project. Before running the client, update the DAPR_HTTP_PORT environment variable in the ActorClient project directory to the port on which Dapr is running in the Kubernetes cluster.

On Linux, MacOS:

export DAPR_HTTP_PORT=3500

Than port-forward the DemoActor service to your local machine:

kubectl port-forward svc/demoactor 3500:3500

Now you can run the client project from the ActorClient directory:

dotnet run