DaprActor

Machine Twin implementation with dapr Actor Model

Run the service, which hostst the MachineActor

$ dapr run --app-id machineactor --app-port 3000 --dapr-http-port 3500 dotnet run

Run client as dapr application

$ dapr run --app-id actorclient --app-port 3000 --dapr-http-port 3500 dotnet run

Run client as console application

The client can be run as console application too.

If you look for a tutorial, please read this: https://github.com/dapr/dotnet-sdk/blob/master/docs/get-started-dapr-actor.md

How does it work?

When one application is started inside of the dapr runtime, the service (deamon) daprd.exe (on Windows) is started. This service establishes the connecttion between your application and all other service placed inside of the dapr runtime. The service daprd acts as a proxy (by outgoing calls) and reverse proxy (by incomming calls) in the SideCar architecture. Every service provides one HTTP and one gRPC endpoint. Applications, running also outside of the runtime, can use these endpoints to communicate with application inside of the dapr environment. Following picture shows the example described in this post.

Talking to actor

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/MachineActor/abc/method/SetDataAsync -d '{ "Temperature": 100, "Speed": 200 }'

On Windows in command prompt:

curl -X POST http://127.0.0.1:3500/v1.0/actors/MachineActor/abc/method/SetDataAsync -d "{ \"Temperature\": 28, \"Speed\": 200 }"

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/MachineActor/abc/method/GetDataAsync

On Windows:

curl -X POST http://127.0.0.1:3500/v1.0/actors/MachineActor/abc/method/GetDataAsync

NOTE

If you get following exception:

Invoke-WebRequest : A parameter cannot be found that matches parameter name 'X'.
At line:1 char:6
+ curl -X POST http://127.0.0.1:3500/v1.0/actors/MachineActor/abc/metho ...
+      ~~
+ CategoryInfo          : InvalidArgument: (:) [Invoke-WebRequest], ParameterBindingException
+ FullyQualifiedErrorId : NamedParameterNotFound,Microsoft.PowerShell.Commands.InvokeWebRequestCommand

Then execute

remove-item alias:\curl