consuming the streaming service

kelvinrfr · Aug 3, 2020 · cf7b1cd · cf7b1cd
1 parent f82ecbf
commit cf7b1cd
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Showing 6 changed files with 55 additions and 7 deletions.
diff --git a/README.md b/README.md
@@ -3,6 +3,8 @@
 In this project I'm doing some tests with this technology.
 
 ## Notes
+- the way to return an "array of results" is through streaming, e.g. `rpc GetDataAsync(GetDataRequest) returns (stream GetDataReply);`
+- the other way is to return an array inside a messege envelop, but this is not too performatic
 - `proto files` = kind of interfaces to define the message format.
 - `rpc SayHello (HelloRequest) returns (HelloReply);` = service definition
 - each message should have a `order identifier`, e.g.:
@@ -11,6 +13,7 @@ In this project I'm doing some tests with this technology.
         string message = 1;
     }
     ```
+- to create new services we should register them individually on Startup `endpoints.MapGrpcService<v1.StreamerService>();`
 - [disabling TLS and making gRPC server run over http (insercure) due to OS compatibility (macOS)](https://docs.microsoft.com/pt-br/aspnet/core/grpc/troubleshoot?view=aspnetcore-3.1&source=docs#unable-to-start-aspnet-core-grpc-app-on-macos)
 - [call insecure (http) gRPC services](https://docs.microsoft.com/pt-br/aspnet/core/grpc/troubleshoot?view=aspnetcore-3.1&source=docs#call-insecure-grpc-services-with-net-core-client)
 

diff --git a/grpc-client-console/Program.cs b/grpc-client-console/Program.cs
@@ -1,29 +1,53 @@
 using System;
 using System.Threading.Tasks;
+using Grpc.Core;
 using Grpc.Net.Client;
-using grpc_server; 
+using grpc_server;
+using grpc_server.v1;
 
 namespace grpc_client_console
 {
     class Program
     {
         const string address = "http://localhost:5000";
+        static readonly GrpcChannel channel = GrpcChannel.ForAddress(address);
 
         static async Task Main(string[] args)
         {
             Console.WriteLine("Waiting server warm up...");
             await Task.Delay(TimeSpan.FromSeconds(5));
 
-            // This switch must be set before creating the GrpcChannel/HttpClient.
+            // Allowing gRPC run over insecure channels
             AppContext.SetSwitch("System.Net.Http.SocketsHttpHandler.Http2UnencryptedSupport", true);
 
-            await GreeterService();
+            Console.WriteLine($"Creating gRPC clients over channel '{address}'...");
+            await CallGreeterService();
+
+            await CallStreamerService();
         }
 
-        private static async Task GreeterService()
+        private static async Task CallStreamerService()
         {
-            Console.WriteLine($"Creating gRPC client over channel '{address}'...");
-            var channel = GrpcChannel.ForAddress(address);
+            Console.WriteLine("Creating streamer client..");
+            var streamerClient = new Streamer.StreamerClient(channel);
+
+            Console.WriteLine("Calling service...");
+            using var streamingReply = streamerClient.GetDataAsync(new GetDataRequest
+            {
+                Seed = 21
+            });
+
+            while (await streamingReply.ResponseStream.MoveNext())
+            {
+                var reply = streamingReply.ResponseStream.Current;
+                Console.WriteLine($"Message received {reply.Datetime} = {reply.Number}");
+            }
+            Console.WriteLine("All messages received");
+        }
+
+        private static async Task CallGreeterService()
+        {
+            Console.WriteLine("Creating greeter client..");
             var greaterClient = new Greeter.GreeterClient(channel);
 
             Console.WriteLine("Calling client...");

diff --git a/grpc-client-console/Protos/v1/streamer.proto b/grpc-client-console/Protos/v1/streamer.proto
@@ -0,0 +1,17 @@
+syntax = "proto3";
+
+option csharp_namespace = "grpc_server.v1";
+
+service Streamer {
+    rpc GetDataAsync(GetDataRequest) returns (stream GetDataReply);
+}
+
+message GetDataRequest
+{
+    int32 seed = 1;
+}
+
+message GetDataReply {
+    int32 number = 1;
+    string datetime = 2;
+}
diff --git a/grpc-client-console/grpc-client-console.csproj b/grpc-client-console/grpc-client-console.csproj
@@ -17,11 +17,14 @@
   </ItemGroup>
   <ItemGroup>
     <Folder Include="Protos\" />
+    <Folder Include="Protos\v1\" />
   </ItemGroup>
   <ItemGroup>
     <None Remove="Protos\greet.proto" />
+    <None Remove="Protos\v1\streamer.proto" />
   </ItemGroup>
   <ItemGroup>
     <Protobuf Include="Protos\greet.proto" GrpcServices="Client" />
+    <Protobuf Include="Protos\v1\streamer.proto" GrpcServices="Client" />
   </ItemGroup>
 </Project>
diff --git a/grpc-server/Services/v1/StreamerService.cs b/grpc-server/Services/v1/StreamerService.cs
@@ -25,7 +25,7 @@ public async override Task GetDataAsync(
             {
                 await responseStream.WriteAsync(new GetDataReply
                 {
-                    Number = random.Next(),
+                    Number = random.Next(maxValue: 100),
                     Datetime = DateTime.UtcNow.ToString()
                 });
                 await Task.Delay(TimeSpan.FromSeconds(1));

diff --git a/grpc-server/Startup.cs b/grpc-server/Startup.cs
@@ -32,6 +32,7 @@ public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
             app.UseEndpoints(endpoints =>
             {
                 endpoints.MapGrpcService<GreeterService>();
+                endpoints.MapGrpcService<v1.StreamerService>();
 
                 endpoints.MapGet("/", async context =>
                 {