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What is gRPC?

Learn the main advantages of gRPC and protobuf.

What is gRPC?

gRPC is a remote procedure call (RPC) framework developed by Google. A client calls a function on the server as if it were local. It uses HTTP/2 for transport and Protocol Buffers for data, so its messages are smaller and faster than JSON-based REST.

// on the client side
resp, err := client.Selam(ctx, &pb.SelamIstek{Ad: "Ada"})

Four call types

gRPC offers four communication styles: unary (one request, one response), server streaming (one request, many responses), client streaming (many requests, one response) and bidirectional streaming. It is common for internal communication between microservices; using it directly from a browser needs an extra layer such as gRPC-Web.

Practice Simulating RPC

Imitate the essence of a gRPC call: type SelamServer struct{} with a method func (SelamServer) Selam(ad string) string returning "Merhaba " + ad. In main, print SelamServer{}.Selam("Ada").

Starter code

main.go
package main

import "fmt"

func main() {
    // buraya yaz
}

Sample solution

main.go
package main

import "fmt"

type SelamServer struct{}

func (SelamServer) Selam(ad string) string { return "Merhaba " + ad }

func main() {
    fmt.Println(SelamServer{}.Selam("Ada"))
}

Expected output

Merhaba Ada

Questions and answers

Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.

1 Which transport protocol does gRPC use?

  • FTP
  • SMTP
  • HTTP/2 Correct answer
  • HTTP/1.0

Explanation: HTTP/2 provides multiple streams and bidirectional streaming over one connection; gRPC is built on it.

2 Data format

Question 
// selam.proto
syntax = "____";
Answer 
// selam.proto
syntax = "proto3";

Explanation: Protocol Buffers is a binary, typed format; smaller and faster than JSON.

3 Call types

Term Meaning
Unary 1 request, 1 response
Server streaming 1 request, many responses
Client streaming Many requests, 1 response
Bidirectional Two-way stream

All lessons in Advanced

1 Reflection

  1. The reflect package
  2. reflect.Type
  3. reflect.Value
  4. Reflecting struct fields
  5. Dynamic call
  6. Summary - Reflection

2 unsafe

  1. The unsafe package
  2. unsafe.Pointer
  3. Sizeof and Alignof
  4. Offsetof
  5. unsafe and slice
  6. Summary - unsafe

3 cgo

  1. What is cgo?
  2. Calling C code
  3. C data types
  4. Go-C conversion
  5. cgo and memory
  6. Summary - cgo

4 plugin

  1. The plugin package
  2. Building a plugin
  3. Loading a plugin
  4. Plugin symbol
  5. Plugin and error
  6. Summary - plugin

5 database/sql

  1. The database/sql package
  2. sql.Open
  3. Query and Exec
  4. Prepared statement
  5. Transaction
  6. Summary - database/sql

6 Middleware

  1. The middleware concept
  2. HTTP middleware
  3. Middleware chain
  4. Logging middleware
  5. Auth middleware
  6. Summary - Middleware

7 gRPC

  1. What is gRPC?
  2. Protobuf definition
  3. Compiling with protoc
  4. gRPC server
  5. gRPC client
  6. Summary - gRPC

8 Project: Microservice

  1. Service skeleton
  2. Database layer
  3. HTTP API
  4. Docker and deployment

9 Docker

  1. Dockerfile
  2. Multi-stage build
  3. scratch image
  4. docker-compose
  5. Build args and labels
  6. Summary - Docker

10 pprof

  1. What is pprof?
  2. CPU profiling
  3. Memory profiling
  4. go test -cpuprofile
  5. The trace tool
  6. Summary - pprof

11 Observability

  1. log/slog
  2. Metrics
  3. Tracing
  4. OpenTelemetry
  5. Health check
  6. Summary - Observability

12 Advanced final

  1. Challenge 1 - Reflection
  2. Challenge 2 - Microservice
  3. Challenge 3 - Performance
  4. Challenge 4 - Database