demo_actor

Example - Dapr virtual actors

This document describes how to create an Actor(DemoActor) and invoke its methods on the client application.

• The actor interface(demo_actor_interface.py). This contains the interface definition for the actor. Actor interfaces can be defined with any name. The interface defines the actor contract that is shared by the actor implementation and the clients calling the actor. Because client may depend on it, it typically makes sense to define it in an assembly that is separate from the actor implementation.
• The actor service(demo_actor_service.py). This implements FastAPI service that is going to host the actor. It contains the implementation of the actor, demo_actor.py. An actor implementation is a class that derives from the base type Actor and implements the interfaces defined in demo_actor_interface.py.
• The actor service for flask(demo_actor_flask.py). This implements Flask web service that is going to host the actor.
• The actor client(demo_actor_client.py) This contains the implementation of the actor client which calls DemoActor's method defined in Actor Interfaces.

Pre-requisites

• Dapr CLI and initialized environment
• Install Python 3.8+

Install requirements

You can install dapr SDK package using pip command:

pip3 install -r demo_actor/requirements.txt

Run in self-hosted mode

1. Run Demo Actor service in new terminal window

   cd demo_actor
   dapr run --app-id demo-actor --app-port 3000 -- uvicorn --port 3000 demo_actor_service:app

   Expected output:

   ...
   == APP == Activate DemoActor actor!
   == APP == has_value: False
   == APP == INFO:     127.0.0.1:50739 - "PUT /actors/DemoActor/1/method/GetMyData HTTP/1.1" 200 OK
   == APP == has_value: False
   == APP == INFO:     127.0.0.1:50739 - "PUT /actors/DemoActor/1/method/GetMyData HTTP/1.1" 200 OK
   == APP == set_my_data: {'data': 'new_data'}
   == APP == INFO:     127.0.0.1:50739 - "PUT /actors/DemoActor/1/method/SetMyData HTTP/1.1" 200 OK
   == APP == has_value: True
   == APP == INFO:     127.0.0.1:50739 - "PUT /actors/DemoActor/1/method/GetMyData HTTP/1.1" 200 OK
   == APP == set reminder to True
   == APP == set reminder is done
   == APP == INFO:     127.0.0.1:50739 - "PUT /actors/DemoActor/1/method/SetReminder HTTP/1.1" 200 OK
   == APP == set_timer to True
   == APP == set_timer is done
   == APP == INFO:     127.0.0.1:50739 - "PUT /actors/DemoActor/1/method/SetTimer HTTP/1.1" 200 OK
   == APP == receive_reminder is called - demo_reminder reminder - b'reminder_state'
   == APP == clear_my_data
   ...
   

2. Run Demo client in new terminal window

   # Run actor client
   cd demo_actor
   dapr run --app-id demo-client python3 demo_actor_client.py

   Expected output:

   ...
   == APP == call actor method via proxy.invoke_method()
   == APP == b'null'
   == APP == call actor method using rpc style
   == APP == None
   == APP == Actor reentrancy enabled: True
   == APP == call SetMyData actor method to save the state
   == APP == call GetMyData actor method to get the state
   == APP == {'data': 'new_data', 'ts': datetime.datetime(2020, 11, 13, 0, 38, 36, 163000, tzinfo=tzutc())}
   == APP == Register reminder
   == APP == Register timer
   == APP == waiting for 30 seconds
   == APP == stop reminder
   == APP == stop timer
   == APP == clear actor state
   

Run DemoActor on Kubernetes

1. Build and push docker image

   $ cd examples/demo_actor/demo_actor
   $ docker build -t [docker registry]/demo_actor:latest .
   $ docker push [docker registry]/demo_actor:latest
   $ cd ..
   

For example, [docker registry] is docker hub account.

2. Follow these steps to create a Redis store.

3. Once your store is created, confirm validate redis.yml file in the deploy directory.

   Note: the redis.yml uses the secret created by bitmany/redis Helm chat to securely inject the password.

4. Apply the redis.yml file: kubectl apply -f ./deploy/redis.yml and observe that your state store was successfully configured!

   component.dapr.io/statestore configured

5. Update docker image location in ./deploy/demo_actor_client.yml and ./deploy/demo_actor_service.yml

6. Deploy actor service and clients

   kubectl apply -f ./deploy/demo_actor_service.yml
   kubectl apply -f ./deploy/demo_actor_client.yml
   

7. See logs for actor service and client

   Logs for actor service sidecar:

   dapr  logs -a demoactor -k
   

   Logs for actor service app:

   kubectl logs -l app="demoactor" -c demoactor
   

   Logs for actor client sidecar:

   dapr  logs -a demoactor-client -k
   

   Logs for actor service app:

   kubectl logs -l app="demoactor-client" -c demoactor-client