gRPC (Google Remote Procedure Call)

• open-source
• language-agnostic
• highly efficient for microservices comm.
• binary serialized Protobuf payloads (Harder to debug)

gRPC over HTTP/2 (default)

• gRPC with HTTP/1.1 (Less Common but Possible)
• reduced latency
• bi-directional streaming - Server streaming, client streaming, and bi-directional streaming.
• multiplexing - multiple calls on a single connection
• load balancing
• built in - Authentication, compression, SSL, and retries

gRPC-Web((For Browser Clients)

• ng/react uses
• gRPC-Web, which uses HTTP/1.1 or HTTP/2 in the browser to communicate with the backend gRPC services

Steps

• proto file : user.proto.bkp
• pom.xml
• mvn compile.
• check target folder for stub.

  <plugin>
                  <groupId>org.xolstice.maven.plugins</groupId>
                  <artifactId>protobuf-maven-plugin</artifactId>
                  <version>0.6.1</version>
                  <executions>
                      <execution>
                          <goals>
                              <goal>compile</goal>
                              <goal>compile-custom</goal>
                          </goals>
                      </execution>
                  </executions>
                  <configuration>
                      <protoSourceRoot>src/main/proto</protoSourceRoot>
                      <pluginId>grpc-java</pluginId>
                  </configuration>
  </plugin>
  

          <!--g-rpc-->
          <dependency>
              <groupId>io.grpc</groupId>
              <artifactId>grpc-netty</artifactId>
              <version>1.57.0</version>
          </dependency>
          <dependency>
              <groupId>io.grpc</groupId>
              <artifactId>grpc-protobuf</artifactId>
              <version>1.57.0</version>
          </dependency>
          <dependency>
              <groupId>io.grpc</groupId>
              <artifactId>grpc-stub</artifactId>
              <version>1.57.0</version>
          </dependency>
  

• client code:

  import io.grpc.ManagedChannel;
  import io.grpc.ManagedChannelBuilder;
  import com.example.grpc.UserProto;
  import com.example.grpc.UserServiceGrpc;
  
  public class UserGrpcClient {
      public static void main(String[] args) {
          ManagedChannel channel = ManagedChannelBuilder.forAddress("localhost", 9090)
              .usePlaintext()
              .build();
  
          UserServiceGrpc.UserServiceBlockingStub blockingStub = UserServiceGrpc.newBlockingStub(channel);
  
          // Create a request
          UserProto.UserRequest request = UserProto.UserRequest.newBuilder()
              .setUserId("123")
              .build();
  
          // Make a gRPC call
          UserProto.UserResponse response = blockingStub.getUser(request);
          System.out.println("User Details: " + response.getName() + ", " + response.getEmail());
  
          channel.shutdown();
      }
  }