gRPC-example

A personal project for learning and practicing the gRPC framework

What's been done

1. Learnt how to use gRPC and Protobuf

   • how to define new Protobuf messages with numerous fields of various types,
   • how to define new Protobuf RPC services with message arguments and results,
   • how to automatically generate gRPC service code for Golang applications,
   • how to run a server with a gRPC service and how to call it via a client,
   • how to send messages via streams in client-side, server-side, and bidirectional streaming.

2. Written an example gRPC service application:

   • added .protobuf files for a message and a service that uses this message,
   • automatically generated source code for a gRPC service in Golang,
   • created own implementation for the non-implemented generated service,
   • created examples of calling service using simple messages and every type of streaming.

About examples

What do they show

Every example show one of client-server interaction type: a simple message exchange or message streaming.

Examples demonstrate how and when the client and the server receive and process messages. All the interactions can be observed since the client and the server write logs to the standard output.

For example, logs of the example3:

2026/05/12 10:43:49 Starting gRPC server
2026/05/12 10:43:49 Server listening at: :49000
2026/05/12 10:43:50 Setting up gRPC client
2026/05/12 10:43:50 /////////////////////////////////////////////////////////////////////
2026/05/12 10:43:50 Example 3: Sending list of requests and returning responses in stream
2026/05/12 10:43:50 /////////////////////////////////////////////////////////////////////
2026/05/12 10:43:50 [CLIENT] Sending list of messages
2026/05/12 10:43:50 [SERVER] Processing messages to stream
2026/05/12 10:43:50 [SERVER] Processing message
2026/05/12 10:43:50 [SERVER] Message 1 of type MESSAGE_TYPE_REQUEST (sent at 2026-05-12 07:43:50.248803307 +0000 UTC)
2026/05/12 10:43:50 [SERVER] Message title: Request message 1
2026/05/12 10:43:50 [SERVER] Message tags: [gRPC message request]
2026/05/12 10:43:50 [SERVER] Message data: Request data
2026/05/12 10:43:50 [SERVER] Message is not last, expecting 4 more messages
2026/05/12 10:43:50 [SERVER] Processing message for 1 seconds
2026/05/12 10:43:51 [SERVER] Sending message to stream
2026/05/12 10:43:51 [SERVER] Processing message
2026/05/12 10:43:51 [SERVER] Message 2 of type MESSAGE_TYPE_REQUEST (sent at 2026-05-12 07:43:50.248803946 +0000 UTC)
2026/05/12 10:43:51 [SERVER] Message title: Request message 2
2026/05/12 10:43:51 [SERVER] Message tags: [gRPC message request]
2026/05/12 10:43:51 [SERVER] Message data: Request data
2026/05/12 10:43:51 [SERVER] Message is not last, expecting 3 more messages
2026/05/12 10:43:51 [SERVER] Processing message for 2 seconds
2026/05/12 10:43:51 [CLIENT] Received response message
2026/05/12 10:43:51 [CLIENT] Message 1 of type MESSAGE_TYPE_RESPONSE (sent at 2026-05-12 07:43:51.275823206 +0000 UTC)
2026/05/12 10:43:51 [CLIENT] Message title: Response to message 1
2026/05/12 10:43:51 [CLIENT] Message tags: [gRPC message response]
2026/05/12 10:43:51 [CLIENT] Message data: Response data
2026/05/12 10:43:51 [CLIENT] Message is not last, expecting 4 more messages
2026/05/12 10:43:53 [SERVER] Sending message to stream
2026/05/12 10:43:53 [SERVER] Processing message
2026/05/12 10:43:53 [SERVER] Message 3 of type MESSAGE_TYPE_REQUEST (sent at 2026-05-12 07:43:50.248804093 +0000 UTC)
2026/05/12 10:43:53 [SERVER] Message title: Request message 3
2026/05/12 10:43:53 [SERVER] Message tags: [gRPC message request]
2026/05/12 10:43:53 [SERVER] Message data: Request data
2026/05/12 10:43:53 [SERVER] Message is not last, expecting 2 more messages
2026/05/12 10:43:53 [SERVER] Processing message for 3 seconds
2026/05/12 10:43:53 [CLIENT] Received response message
2026/05/12 10:43:53 [CLIENT] Message 2 of type MESSAGE_TYPE_RESPONSE (sent at 2026-05-12 07:43:53.277063254 +0000 UTC)
2026/05/12 10:43:53 [CLIENT] Message title: Response to message 2
2026/05/12 10:43:53 [CLIENT] Message tags: [gRPC message response]
2026/05/12 10:43:53 [CLIENT] Message data: Response data
2026/05/12 10:43:53 [CLIENT] Message is not last, expecting 3 more messages
2026/05/12 10:43:56 [SERVER] Sending message to stream
2026/05/12 10:43:56 [SERVER] Processing message
2026/05/12 10:43:56 [SERVER] Message 4 of type MESSAGE_TYPE_REQUEST (sent at 2026-05-12 07:43:50.248804234 +0000 UTC)
2026/05/12 10:43:56 [SERVER] Message title: Request message 4
2026/05/12 10:43:56 [SERVER] Message tags: [gRPC message request]
2026/05/12 10:43:56 [SERVER] Message data: Request data
2026/05/12 10:43:56 [SERVER] Message is not last, expecting 1 more messages
2026/05/12 10:43:56 [SERVER] Processing message for 4 seconds
2026/05/12 10:43:56 [CLIENT] Received response message
2026/05/12 10:43:56 [CLIENT] Message 3 of type MESSAGE_TYPE_RESPONSE (sent at 2026-05-12 07:43:56.2793014 +0000 UTC)
2026/05/12 10:43:56 [CLIENT] Message title: Response to message 3
2026/05/12 10:43:56 [CLIENT] Message tags: [gRPC message response]
2026/05/12 10:43:56 [CLIENT] Message data: Response data
2026/05/12 10:43:56 [CLIENT] Message is not last, expecting 2 more messages
2026/05/12 10:44:00 [SERVER] Sending message to stream
2026/05/12 10:44:00 [SERVER] Processing message
2026/05/12 10:44:00 [SERVER] Message 5 of type MESSAGE_TYPE_REQUEST (sent at 2026-05-12 07:43:50.248804436 +0000 UTC)
2026/05/12 10:44:00 [SERVER] Message title: Request message 5
2026/05/12 10:44:00 [SERVER] Message tags: [gRPC message request]
2026/05/12 10:44:00 [SERVER] Message data: Request data
2026/05/12 10:44:00 [SERVER] Message is last, no more messages expected
2026/05/12 10:44:00 [SERVER] Processing message for 5 seconds
2026/05/12 10:44:00 [CLIENT] Received response message
2026/05/12 10:44:00 [CLIENT] Message 4 of type MESSAGE_TYPE_RESPONSE (sent at 2026-05-12 07:44:00.282500532 +0000 UTC)
2026/05/12 10:44:00 [CLIENT] Message title: Response to message 4
2026/05/12 10:44:00 [CLIENT] Message tags: [gRPC message response]
2026/05/12 10:44:00 [CLIENT] Message data: Response data
2026/05/12 10:44:00 [CLIENT] Message is not last, expecting 1 more messages
2026/05/12 10:44:05 [SERVER] Sending message to stream
2026/05/12 10:44:05 [CLIENT] Received response message
2026/05/12 10:44:05 [CLIENT] Message 5 of type MESSAGE_TYPE_RESPONSE (sent at 2026-05-12 07:44:05.286692301 +0000 UTC)
2026/05/12 10:44:05 [CLIENT] Message title: Response to message 5
2026/05/12 10:44:05 [CLIENT] Message tags: [gRPC message response]
2026/05/12 10:44:05 [CLIENT] Message data: Response data
2026/05/12 10:44:05 [CLIENT] Message is last, no more messages expected

How to run examples

You can run all the examples by running the application:

go run ./cmd/examples/...

To choose a certain example you can pass a -example flag. For example,

go run ./cmd/examples/... -example=example3

if -example=all or the flag is omitted then all the examples will be run.