go-grpc-gateway-server
This repository provides an example for go based microservice. Go micro services developed based on gRPC protobuf's and also uses gRPC gateway as a reverse proxy to support JSON clients/requests.
Dev pre-requisites
-
golang
brew install go Note: Make sure to have go1.17.2 or latest -
Docker
brew install docker -
PgAdmin for Postgres DB, download and this is optional if you prefer cli
-
Update env
vi ~/.zshrc add below entries, save & exit. export GOPATH=$HOME/go export PATH=$PATH:$GOPATH/bin export GONOPROXY="github.com,gopkg.in,go.uber.org"source ~/.zshrc
Install protoc
If you have Homebrew (which you can get from https://brew.sh), just run:
brew install protobuf
If you see any error messages, run brew doctor, follow any recommended fixes, and try again. If it still fails, try instead:
brew upgrade protobuf
Alternately, run the following commands:
PROTOC_ZIP=protoc-3.14.0-osx-x86_64.zip
curl -OL https://github.com/protocolbuffers/protobuf/releases/download/v3.14.0/$PROTOC_ZIP
sudo unzip -o $PROTOC_ZIP -d /usr/local bin/protoc
sudo unzip -o $PROTOC_ZIP -d /usr/local 'include/*'
rm -f $PROTOC_ZIP```
go install \
github.com/grpc-ecosystem/grpc-gateway/v2/protoc-gen-grpc-gateway@latest \
github.com/grpc-ecosystem/grpc-gateway/v2/protoc-gen-openapiv2@latest \
google.golang.org/protobuf/cmd/protoc-gen-go@latest \
google.golang.org/grpc/cmd/protoc-gen-go-grpc@latest
Note: Make sure protobuf's installed correctly by running protoc --version
Generate protobuf's
Note: Required this step only when you make changes to .proto file or introduce a new one
cd pkg/api
go generate ./...
(or) alternative try below in case you did not set GOPATH
env PATH="$HOME/go/bin:$PATH" go generate ./...
Following 3 files are auto generated ones with above command
api/test_api.pb.go
api/test_api.pb.gw.go
api/test_api_grpc.pb.go
Build and Run Docker
docker compose build
docker compose up
Instructions for Developers
How to add a new service & test?
This section demonstrates, how to add a new grpc gateway service, implement and test it in local.
Note: Follow naming standards from here: https://cloud.google.com/apis/design/naming_convention#method_names
####1. Add new proto changes Lets add a test api called SayHello to pkg/api/test_api.proto
// SayHello service generates a greeting message
rpc SayHello(SayHelloRequest) returns (SayHelloResponse) {
option (google.api.http) = {
post: "/v1/greet"
body: "*"
};
}
Add request SayHelloRequest & response SayHelloResponse objects declared above
// Request Message for greeting service
message SayHelloRequest {
string name = 1;
}
// Response Message for greeting service
message SayHelloResponse {
string msg = 1;
}
####2. generate protobufs
cd pkg/api
go generate ./...
(or) alternative try below in case you did not set GOPATH
env PATH="$HOME/go/bin:$PATH"
####3. Implement service handler
func (s *Server) SayHello(ctx context.Context, request *api.SayHelloRequest) (*api.SayHelloResponse, error) {
s.Log.Info("Hit to SayHello service and Request=%s", request.Name)
response := &api.SayHelloResponse{Msg: "Hello " + request.Name + "!!"}
return response, nil
}
####4. Build, Deploy and Test
docker compose build
docker compose up
curl -X POST -d '{"name": "John Doe" }' -H 'Content-Type: application/json'
http://localhost:9091/v1/greet
Response:
{"msg": "Hello John Doe!!"}
