Dapr Actor Demos

EvilCorp Actor Demo

A fictional company called EvilCorp 😈 wants their employees to be more productive and have decided to implement a system with smart alarm clocks that will wake up their employees at 7am. If the employees have not acknowledged the alarm within 3 snoozes, the alarm will send a message to the headquarters to lay off the employee 😱.

The front-end of the demo is a basic HTML page that uses p5js to draw the information on the page. The back-end is a Dapr application written in ASP.NET that uses actors for the headquarters, the regional office, the employees, and the alarm clocks. Communication between the back-end and the front-end is realized with Ably.

When the demo is run you'll see a realtime display of the alarm clocks in the EvilCorp Dashboard. Alarm clocks are represented by a square. The color of the square indicates the state of the alarm clock:

Green: Alarm has been acknowledged on time.
Blue: Alarm has been snoozed.
Red: Alarm has been snoozed for too long, employee will be laid off.

InitActors sequence diagram

sequenceDiagram
    participant A as API
    participant S as Simulation
    participant HQ as Headquarters
    participant RO as RegionalOffice
    participant AC as AlarmClock
    participant E as Employee

A->>S: CreateActorProxy
A->>S: InitActorsAsync
S->>HQ: CreateActorProxy
S->>HQ: SetRegionalOfficeIdsAsync
S->>HQ: SetEmployeeIdsAsync
S->>RO: CreateActorProxy
S->>RO: SetRegionalOfficeDataAsync
loop for 1 to employeeCount
    S->>AC: CreateActorProxy
    S->>AC: SetAlarmClockDataAsync
    S->>E: CreateActorProxy
    S->>E: SetEmployeeDataAsync
end
S->>RO: SetAlarmClockEmployeeMappingAsync

StartTime sequence diagram

sequenceDiagram
    participant A as API
    participant S as Simulation
    participant HQ as Headquarters
    participant RO as RegionalOffice
    participant AC as AlarmClock
    participant E as Employee

A->>S: StartTimeAsync
S->>HQ: CreateActorProxy
S->>HQ: GetRegionalOfficeIdsAsync
loop for each regional office
    S->>RO: CreateActorProxy
    S->>RO: GetRegionalOfficeDataAsync
    S->>RO: SetAlarmClockTimeAsync
    loop for each alarm clock
        RO->>AC: CreateActorProxy
        RO->>AC: SetSyncTimeAsync
        AC->>AC: RegisterTimerAsync
    end
end

loop every second
    AC->>AC: IncrementTimeHandler
    alt time => alarm time
        AC->>AC: AlarmHandler
        AC->>RO: CreateActorProxy
        AC->>RO: GetEmployeeIdAsync
        AC->>E: CreateActorProxy
        AC->>E: GetAlarmResponse
        alt employee acknowledged
            AC->>AC: StopTimerAsync
        else employee snoozed
            AC->>AC: SnoozeAlarmAsync
        end
        AC->>AC: GetSnoozeCountAsync
        alt snooze count > 3
            AC->>RO: CreateActorProxy
            AC->>RO: FireEmployeeAsync
            RO->>E: CreateActorProxy
            RO->>E: SetIsFiredAsync
            RO->>HQ: CreateActorProxy
            RO->>HQ: FireEmployeeAsync
        end
    end
end

Prerequisites for running the demo locally

Docker Desktop
Dapr CLI
Ably account (free tier is sufficient)

Configuring the demo

Back-end

Copy the Ably API Root key from the Ably portal.
Rename the EvilCorpDemo/EvilCorp.Api/secrets.json.example file to EvilCorpDemo/EvilCorp.Api/secrets.json and paste Ably API key in the AblyApiKey field:
```
{
    "AblyApiKey": "YOUR_ABLY_API_KEY_HERE"
}
```
The secrets.json file is excluded from source control by the .gitignore file, so you don't have to worry the API key will be exposed to the public.
Use the terminal to navigate to the EvilCorpDemo folder and build the solution:
```
dotnet build
```

Front-end

Rename the EvilCorpDemo/EvilCorp.FrontEnd/secrets.json.example file to EvilCorpDemo/EvilCorp.FrontEnd/secrets.json and paste Ably API key in the AblyApiKey field:
```
{
    "AblyApiKey": "YOUR_ABLY_API_KEY_HERE"
}
```
Use the terminal to navigate to the EvilCorpDemo/EvilCorp.FrontEnd folder and install the dependencies for the front-end:
```
npm install
```

Running the demo

Use the terminal to navigate to the EvilCorpDemo folder.
Use Dapr multi-app run to start both the back-end and front-end with a single command:
```
dapr run -f .
```
The EvilCorpDemo/dapr.yaml file contains the configuration of the apps that will be started.
Open the front-end in a browser and click the Connect button. This establishes a connection with Ably Realtime.
Enter the number of employees you want to simulate and click the Create actors button. This will create actors for the EvilCorp head quarters, the regional office, the employees and the alarm clocks.

Be careful not to create too many employees. The free tier of Ably is rate-limited to handle 70 messages per second. More info in the Ably limits docs.
Click the Start time button to start the simulation. This will set the time of all the alarm clocks and after each two seconds 10 minutes will pass in the simulation. Once the alarm clocks reach 7:00, the employee actors will randomly acknowledge or snooze the alarm.

Basic Actor Samples

The BasicActorSamples folder in this repo contains a number of samples that demonstrate the basic functionality of Dapr Actors. The samples are written in C# and use the Dapr Actors .NET SDK.

The Actor interactions are performed via the Dapr HTTP API and are listed in the basic-actor-samples.http file.

HelloWorldActor

The HelloWorldActor is a stateless actor and contains two methods that can be invoked.

The SayHelloWorld method without parameters:

GET {{ daprHttp }}/v1.0/actors/HelloWorldActor/user1/method/SayHelloWorld
dapr-app-id: basic-actor-demos

The SayHello method with a parameter:

POST {{ daprHttp }}/v1.0/actors/HelloWorldActor/user2/method/SayHello
dapr-app-id: basic-actor-demos
Content-Type: application/json

"Rene"

StatefulActor

The StatefulActor is a stateful actor and contains two methods, one to set the state and one to get the state.

POST {{ daprHttp }}/v1.0/actors/StatefulActor/user2/method/SetGreeting
dapr-app-id: basic-actor-demos
Content-Type: application/json

"Hello from StatefulActor!"

GET {{ daprHttp }}/v1.0/actors/StatefulActor/user2/method/GetGreeting
dapr-app-id: basic-actor-demos

The state can also be set via the Dapr Actor state endpoint:

POST {{ daprHttp }}/v1.0/actors/StatefulActor/user2/state
dapr-app-id: basic-actor-demos
Content-Type: application/json

[
    {
        "operation": "upsert",
        "request": {
            "key": "greeting",
            "value": "Hello from StatefulActor (state endpoint)!"
        }
    }
]

And retrieved via the Dapr Actor state endpoint:

GET {{ daprHttp }}/v1.0/actors/StatefulActor/user2/state/greeting
dapr-app-id: basic-actor-demos

TimerActor

The TimerActor is an actor that contains a timer. The timer is started when the CreateTimer method is called and will trigger the execution of the SnoozeHandler method every 5 seconds.

POST {{ daprHttp }}/v1.0/actors/TimerActor/alarmclock1/method/CreateTimer
dapr-app-id: basic-actor-demos

The timer can be deleted via the Dapr Actor timers endpoint:

DELETE {{ daprHttp }}/v1.0/actors/TimerActor/alarmclock1/timers/snooze
dapr-app-id: basic-actor-demos

ReminderActor

The ReminderActor is an actor that contains a reminder, a stateful version of a timer.

POST {{ daprHttp }}/v1.0/actors/ReminderActor/alarmclock2/reminders/snooze
dapr-app-id: basic-actor-demos
Content-Type: application/json

{
    "dueTime" : "0h0m3s0ms",
    "period" : "R3/P0Y0M0W0DT0H0M10S"
}

The reminder can be deleted via the Dapr Actor reminders endpoint:

DELETE {{ daprHttp }}/v1.0/actors/ReminderActor/alarmclock2/reminders/snooze
dapr-app-id: basic-actor-demos

ActorToActor

The ActorToActor sample demonstrates how to call an actor from another actor. The CallHelloWorld method creates a proxy of the HelloWorldActor and invokes the SayHelloWorld method on it. This requires the Actor ID of the HelloWorldActor to be passed as a parameter.

POST {{ daprHttp }}/v1.0/actors/ActorToActor/id1/method/CallHelloWorld
dapr-app-id: basic-actor-demos
Content-Type: application/json

"helloWorldId1"

Resources

More information

Any questions or comments about this sample? Join the Dapr discord and post a message the APIS > #actors channel. Have you made something with Dapr? Post a message in the #show-and-tell channel, we love to see your creations!

diagrid-labs/dapr-actor-demos