d10085-micro-simple-rpc.md

# 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 \( service: up-atlas \) ```java 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 \( service: up-atlas \) ```java 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 io.zerows.annotations.infix.Rpc; @Queue public class SingleWorker { @Rpc private transient RpcClient client; @Address("ZERO://RPC/FIRST") public void sayHello(final Message 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 \( service: up-coeus \) ```java 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](http://localhost:6100/api/rpc/lang.yu) **Method** : GET **Response** : ```json { "data": { "name": "lang.yu" } } ``` ## 4. Console When you send the request you should see some message output: **service: up-atlas** ```shell [ 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** ```shell [ ZERO ] --> ( Terminator ) found, will provide response. method ...... {"name":"lang.yu"} [ ZERO ] Current flow is Envelop, return type = class io.vertx.up.argument.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 `io.zerows.annotations.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. \`