Goa Demo Service

HTTP service created with the Goa v3 framework. It can be used as an example and a starting point for writing microservices with Goa.

main.go

The example provides a stripped down main.go file for wiring up the Goa components with the service implementation.

It also shows how to use multiple services in the Goa DSL to provide separate logical implementations of components inside the micro-service. For example, liveness and readiness endpoints are implemented in a separate component and are not mixed with the weather service business logic. The Swagger documentation is also exposed as a separate service.

Example:

var _ = Service("weather", func() {
	Description("The weather service returns information for a given location.")
	Method("WeatherQuery", func() {
		HTTP(func() {
			POST("/v1/weather")
			...
		})
	})
})

var _ = Service("healthcheck", func() {
	Description("The healthcheck service is used report on the liveness and readiness status of the weather service.")

	Method("liveness", func() {
		HTTP(func() {
			GET("/liveness")
			...
		})
	})

	Method("readiness", func() {
		HTTP(func() {
			GET("/readiness")
			...
		})
	})
})

goagen.sh

Goa code generation doesn't work when you use a vendor directory. This means that if you explicitly build your project with vendor support enabled, goa gen will fail.

The goagen.sh script is a work-around that limitation. It alters GOFLAGS so that the goa code generation doesn't look for dependencies in the vendor directory.

If you don't use the vendor mode, then you may not need to use this script.

Docker environment

You can start the service with docker-compose for easier local development. The dockerized environment uses a Go watcher which automatically rebuilds the project after some .go files are changed, which may be handy.

To start the service and see the logs of the container, just type:

docker-compose up -d
docker-compose logs -f

IMPORTANT: If you want the service to run correctly, you should provide an API key for https://openweathermap.org/api. The sample one deadbeef placed inside the docker-composes.yml won't work, as it is not a real API key provisioned by the openweather service.

Test the service

After the service is up and running, say for example at port 8080, you can hit it with curl:

curl -vvv localhost:8080/v1/liveness