Micro, Simple Rpc

From this tutorials we started to move to Rpc tutorials in zero system, at first let’s move to the first example.

1. Services

The whole example web request flow should be as following picture described:

Here are three projects in current demo:

Http Port	Ipc Port	Ipc Service Name	Project	Role
6100	–	–	up-athena	Api Gateway
6201	–	–	up-atlas	Common Service
6401	6411	ipc-coeus	up-coeus	Coordinator A

2. Source Code

Although above picture described complex micro environment web request flow, but in zero system, developers do not care about service details such as Discovery, Registry, Communication

2.1. SingleApi ( service: up-atlas )

package up.god.micro.rpc;

import io.vertx.up.annotations.Address;
import io.vertx.up.annotations.EndPoint;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;

@EndPoint
@Path("/api")
public interface SingleApi {

    @Path("rpc/{name}")
    @GET
    @Address("ZERO://RPC/FIRST")
    String sayHello(@PathParam("name") String name);
}

2.2. SingleWorker ( service: up-atlas )

package up.god.micro.rpc;

import io.vertx.core.eventbus.Message;
import io.vertx.core.json.JsonObject;
import io.vertx.up.aiki.Ux;
import io.vertx.up.annotations.Address;
import io.vertx.up.annotations.Queue;
import io.vertx.up.atom.Envelop;
import io.vertx.up.plugin.rpc.RpcClient;

import jakarta.inject.infix.Rpc;

@Queue
public class SingleWorker {

    @Rpc
    private transient RpcClient client;

    @Address("ZERO://RPC/FIRST")
    public void sayHello(final Message<Envelop> message) {
        final String name = Ux.getString(message);
        final JsonObject params = new JsonObject().put("name", name);
        this.client.connect("ipc-coeus", "RPC://SAY/HELLO", params, res -> {
            if (res.succeeded()) {
                message.reply(Envelop.success(res.result()));
            } else {
                res.cause().printStackTrace();
                message.reply(Envelop.failure(res.cause().getMessage()));
            }
        });
    }
}

2.3. HelloInsider ( service: up-coeus )

package up.god.ipc;

import io.vertx.core.json.JsonObject;
import io.vertx.up.annotations.Ipc;
import io.vertx.up.atom.Envelop;

public class HelloInsider {

    @Ipc("RPC://SAY/HELLO")
    public Envelop sayHello(final Envelop envelop) {
        final JsonObject data = envelop.data();
        System.out.println(data);
        return Envelop.success(data);
    }
}

3. Testing

Then start above three services and testing with Postman ( The 6100 is api gateway port )

URL : http://localhost:6100/api/rpc/lang.yu

Method : GET

Response :

{
    "data": {
        "name": "lang.yu"
    }
}

4. Console

When you send the request you should see some message output:

service: up-atlas

[ ZERO ] ( Rpc Client ) Build channel ( host = 10.0.0.7, port = 6411, hashCode = 58401608 )
[ ZERO ] ( Rpc Client ) Final Traffic Data will be IpcData......
[ ZERO ] ( Rpc Client ) Response Json data is {"name":"lang.yu"}

service: up-coeus

[ ZERO ] --> ( Terminator ) found, will provide response. method ......
{"name":"lang.yu"}
[ ZERO ] Current flow is Envelop, return type = class io.vertx.up.atom.Envelop

5. Summary

From this demo, you could see the whole web request workflow has been finished in zero system. Here we used another new annotation jakarta.inject.infix.Rpc, this annotation is defined by zero system. You can inject RpcClient directly here, the reference of RpcClient is the type of io.vertx.up.plugin.rpc.RpcClient.

Another annotation to describe Rpc address is io.vertx.up.annotations.Ipc , this annotation could tell zero system which method will be executed in Rpc Server, in further tutorials we’ll introduce more usage of these annotations here.

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