grpc-gateway-example

gRPC Gateway Example

This repo contains an example usage of grpc gateway (https://github.com/grpc-ecosystem/grpc-gateway).

Developing

Install protoc (https://github.com/protocolbuffers/protobuf)

brew install protobuf

Run

go mod tidy

go install \
    github.com/grpc-ecosystem/grpc-gateway/protoc-gen-grpc-gateway \
    github.com/grpc-ecosystem/grpc-gateway/protoc-gen-swagger \
    github.com/golang/protobuf/protoc-gen-go \
    golang.org/x/tools/cmd/stringer \
    github.com/vektra/mockery/cmd/mockery \
    github.com/golangci/golangci-lint/cmd/golangci-lint

Add $GOBIN to path

export PATH=$PATH:~/go/bin

Code generation

From root of repo run:

go generate ./...

This will re-generate required code. Go generate will generate grpc server/client stubs, the grpc gateway reverse proxy and open api definition for the protobuf definition. These commands can be run independently by running the following commands.

Generate gRPC server/client stub

protoc -I. --go_out=plugins=grpc,paths=source_relative:./ api.proto

Generate reverse-proxy using protoc-gen-grpc-gateway

protoc -I. --grpc-gateway_out=logtostderr=true,paths=source_relative:./ api.proto 

Generate swagger definitions using protoc-gen-swagger

protoc -I. --swagger_out=disable_default_errors=true,logtostderr=true:../api/openapi-spec api.proto

Run PostgreSQL database

To install PostgreSQL (https://www.postgresql.org/) run:

brew install postgresql

Run the docker image postgres (https://hub.docker.com/_/postgres):

docker run --rm --name beers -e POSTGRES_PASSWORD=ilovebeer -p 5432:5432 -v $HOME/Git/github.com/bvwells/grpc-gateway-example/pkg/infrastructure/postgres:/var/lib/postgresql/data postgres

NOTE: The environment variable POSTGRES_PASSWORD should be set to a secret when running in a real environment.

Connect to running instance:

psql -h localhost -U postgres -d postgres

To create the beers database run:

CREATE DATABASE BEERS;

Connect to the database:

\c beers

To create the beers table run:

CREATE TABLE BEERS (
  id VARCHAR(36) PRIMARY KEY,
  name TEXT,
  type INT,
  brewer TEXT,
  country TEXT
);

Some useful psql commands:

List databases:

\l 

Connect to a database:

\c table_name username

List tables:

\dt 

Describe a table:

\d table_name

Help:

\? table_name

TODOs

• What to do with request headers?