How to access Flink statefun function

Question

flink playground gives a demo as below:

public final class GreeterAppServer {

  public static void main(String[] args) {
    final StatefulFunctions functions = new StatefulFunctions();
    functions.withStatefulFunction(UserFn.SPEC);
    functions.withStatefulFunction(GreetingsFn.SPEC);

    final RequestReplyHandler requestReplyHandler = functions.requestReplyHandler();
    final Undertow httpServer =
        Undertow.builder()
            .addHttpListener(1108, "0.0.0.0")
            .setHandler(new UndertowHttpHandler(requestReplyHandler))
            .build();
    httpServer.start();
  }

how to access the function by a http request? post?get?

You can find the complete documentation at statefun.io, and in the playground try `docker-compose up` — Igal, Jan 13 '22 at 16:44
statefun master will access the http server's endpoint specified in `urlPathTemplate` of `io.statefun.endpoints.v2/http` spec in `module.yaml`. it's going to be a POST request because master needs to use request body to send byte array — mangusta, Sep 30 '22 at 07:51

score 1 · Answer 1 · answered Mar 11 '22 at 11:17

When you set your stateful function like this

functions.withStatefulFunction(UserFn.SPEC);

you actually register your function as a handler to http server.

Next thing you have to do is to define which endpoint your function will be using.

  static final TypeName TYPENAME = TypeName.typeNameOf("greeter.fns", "user");
  static final StatefulFunctionSpec SPEC =
      StatefulFunctionSpec.builder(TYPENAME)
          .withValueSpecs(SEEN_COUNT, SEEN_TIMESTAMP_MS)
          .withSupplier(UserFn::new)
          .build();

In the example above, stateful function is registered to the endpoint greeter.fns/user. Ref: https://github.com/apache/flink-statefun-playground/blob/main/java/greeter/src/main/java/org/apache/flink/statefun/playground/java/greeter/UserFn.java

This should also be defined in your module.yaml file as below. Ref: https://github.com/apache/flink-statefun-playground/blob/main/java/greeter/module.yaml

functions: greeter.fns/*

Finally, you configure your module.yaml as an environment in your docker-compose.yml. Ref: https://github.com/apache/flink-statefun-playground/blob/main/java/greeter/docker-compose.yml

volumes:
  - ./module.yaml:/module.yaml

this doesn't answer the question – mangusta Sep 30 '22 at 07:53 — mangusta, Sep 30 '22 at 07:53

How to access Flink statefun function

1 Answers1