grpc-playground

grpc-playground is a small gRPC + Protobuf learning project. It is organized as a set of lesson-style demos that show how to build and use protobuf messages, gRPC services, interceptors, deadlines, streaming calls, validation, and TLS.

What is in here

• src/main/proto — protobuf definitions for each lesson section
• src/main/java — demo services, clients, repositories, interceptors, and shared helpers
• src/test/java — JUnit tests that exercise each lesson like runnable examples
• src/test/resources — TLS certificates and docker-compose assets used by the demos/tests

Main package layout

The Java packages are grouped by section:

• com.conellimo.common — shared server bootstrap and demo entrypoints
• com.conellimo.sec01 to com.conellimo.sec05 — protobuf basics and schema evolution
• com.conellimo.sec06 to com.conellimo.sec08 — unary, streaming, flow control, and game-style RPCs
• com.conellimo.sec09 to com.conellimo.sec10 — request validation examples
• com.conellimo.sec11 to com.conellimo.sec13 — deadlines, channel behavior, interceptors, security, and TLS

Prerequisites

• Java 21
• Maven 3.9+

Build

mvn -DskipTests package

Test

mvn test

Run a demo server

There is no Maven run plugin configured here, so the simplest way to launch a demo is from your IDE. The shared demo entrypoint is:

• com.conellimo.common.Demo

You can also run any section-specific main class directly from the IDE.

Notes

• This is a playground project, not a production application.
• Many services intentionally use hardcoded data, fixed ports, and sleeps to make gRPC behavior easy to observe.
• Some classes are demo-only helpers used to keep the lessons simple.