Weather Config REST API - Go REST API

Sample REST Go api to get locations and regions to be used by Ruby on Rails weather website.

Goals of this service

Create sample CRUD REST api in Go which has :

• Go REST api and its dependencies like mongodb, run locally via docker-compose
• Integ testing via newman and docker-compose up postman_checks
• Follow REST naming conventions
• Use swagger for documentation
• Well defined interfaces for model, domain, controller
• All commands can be run via Makefile targets
• Deploy service and swagger docs via docker
• Code coverage, unit and integration tests

Design Patterns / Best practices

Use docker-compose to build and run go service, mongodb, swagger and newman

• https://github.com/gadzooks/weather-go-api/blob/master/docker-compose.yml
• https://github.com/gadzooks/weather-go-api/blob/master/Dockerfile

# start REST api and its dependency mongodb
docker-compose up app

# run integ tests via newman
docker-compose up postman_check

Use middleware to handle tasks like CORS, logging request performance etc

//ServeHTTP handles the request by passing it to the real
//handler and logging the request details
func (l *Logger) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	start := time.Now()
	l.handler.ServeHTTP(w, r)
	log.Info().Msgf("%s %s %v", r.Method, r.URL.Path, time.Since(start))
}

Use middleware to add unique reqId per request to context

6:07AM INF service/v2/place_service.go:41 > insert location : {ObjectID("000000000000000000000000") north bend snowqualmie_region North Bend 47.497428 -121.786648 db086e5e85941a02ae188f726f7e9e2c}
 reqId=74590ef0-2c7b-4e62-bfef-03ae13fa85a3
6:07AM INF service/v2/place_service.go:47 > inserted location with id : 5f30e4046c7600d75072329d reqId=74590ef0-2c7b-4e62-bfef-03ae13fa85a3
6:07AM INF middleware/request_logger.go:19 > POST /v2/locations 3.15215768s reqId=74590ef0-2c7b-4e62-bfef-03ae13fa85a3

Follow REST naming convention and swagger documentation style

	// FindLocations swagger:route GET /locations locations findLocations
	//
	// Finds a location set
	//
	// Consumes:
	// - application/json
	//
	// Produces:
	// - application/json
	//
	// Responses:
	// 200: []location
	api.HandleFunc("/locations", placesCtrl.FindLocations).Methods("GET")

	api.HandleFunc("/regions", placesCtrl.CreateRegion).Methods(http.MethodPost)
	api.HandleFunc("/region/{id:[0-9a-zA-Z]+}", placesCtrl.GetRegion).Methods(http.MethodGet)
	api.HandleFunc("/region/{id:[0-9a-zA-Z]+}", placesCtrl.UpdateRegion).Methods(http.MethodPut)
	api.HandleFunc("/region/{id:[0-9a-zA-Z]+}", placesCtrl.DeleteRegion).Methods(http.MethodDelete)

Rest controller(s) expose endpoints via PlaceController interface

type PlaceController interface {
	FindLocations(w http.ResponseWriter, r *http.Request)
	FindRegions(w http.ResponseWriter, r *http.Request)
}

Handle errors and return the correct http response codes

if errors.Is(err, v2.InvalidInputError) {
    log.Info().Msg(err.Error())
	w.WriteHeader(http.StatusBadRequest)
}

Service package handles business logic via PlaceService interface

// PlaceService is responsible for querying locations and regions
type PlaceService interface {
	GetLocations() ([]model.Location, error)
	GetRegions() ([]model.Region, error)
}

// NewPlaceServiceImpl implements NewPlaceService
type NewPlaceServiceImpl struct {
	client client.StorageClient
}

Client package handles external clients

// StorageClient queries location db
type StorageClient interface {
	QueryLocations(dataDir string) (map[string]model.Location, error)
	QueryRegions(dataDir string) (map[string]model.Region, error)
}

Model pacakge contains Data Transfer Objects (DTOs)

/*
snowqualmie_region:
  search_key: '04d37e830680c65b61df474e7e655d64'
  description: 'Snowqualmie Region'
*/
type Region struct {
	Name        string `json:"name"`
	SearchKey   string `json:"searchKey"`
	Description string `json:"description"`
}

Testing

• integ testing using local mongo, postman and newman

docker-compose -f docker-compose.yml -f docker-compose.test.yml up postman_checks

• we use gomock and mocken

# to install
go get github.com/golang/mock/gomock
go get github.com/golang/mock/mockgen
mockgen -source=controller/place_controller.go -destination=controller/place_controller_mock.go -package=controller

• example integration test :

func TestGetLocations(t *testing.T) {
	req, err := http.NewRequest("GET", "/locations", nil)
	if err != nil {
		t.Fatal(err)
	}
	rr := httptest.NewRecorder()
	storageClient := client.NewStorageClient("../data")
	svc := service.NewPlaceService(storageClient)
	placesCtrl := controller.NewPlaceController(svc)

	handler := http.HandlerFunc(placesCtrl.FindLocations)
	handler.ServeHTTP(rr, req)
	if status := rr.Code; status != http.StatusOK {
		t.Fatalf("handler returned wrong status code: got %v want %v",
			status, http.StatusOK)
	}

	// Check the response body is what we expect.
	expected := 26
	var result *[]model.Location
	err = json.Unmarshal(rr.Body.Bytes(), &result)
	if err != nil {
		t.Fatalf("error unmarshaling results : %v", err)
	}
	if len(*result) != expected {
		t.Fatalf("got %v want %v",
			len(*result), expected)
	}
}

we use swagger to generate living documentation

https://goswagger.io/

build / generate mocks / run tests is via Makefile targets

https://github.com/gadzooks/weather-go-api/blob/master/Makefile

dependencies

we use dep to mange dependencies

code coverage via go test

https://github.com/gadzooks/weather-go-api/blob/master/coverage.out

Todo

• postman and newman tests
• deploy with kubernetes, alongside other apps
• use different envs : dev, staging, prod
• JWT auth ? for service to service authentication
• connecting to mongodb to get props