Generating Skeleton with API

First we need to add service to workspace:

$ mify add service counting-backend

For this tutorial we're using Go service template which tries to follow this layout (https://github.com/golang-standards/project-layout). This is not an official standard project layout, because Go doesn't have one, but it's pretty common.

Now we need to define the API for this service. Open OpenAPI schema file, which is located at schemas/counting-backend/api/api.yaml and you will see this schema:

openapi: "3.0.0"
info:
  version: 1.0.0
  title: counting-backend
  description: Service description
  contact:
    name: Maintainer name
    email: Maintainer email
servers:
  - url: counting-backend.example.com
paths: {}
# Example of a handler, uncomment and remove the above 'paths: {}' line.
# Check Petstore OpenAPI example for more possible options:
# https://github.com/OAI/OpenAPI-Specification/blob/main/examples/v3.0/petstore-expanded.yaml
#
# paths:
#   /path/to/api:
#     get:
#       summary: sample handler
#       responses:
#         '200':
#           description: OK
#           content:
#             application/json:
#               schema:
#                 $ref: '#/components/schemas/PathToApiResponse'
# components:
#   schemas:
#     PathToApiResponse:
#       type: object
#       properties:
#         value:
#           type: string
#       required:
#         - value

Let's add our handler definition to it:

openapi: "3.0.0"
info:
  version: 1.0.0
  title: counting-backend
  description: Service description
  contact:
    name: Maintainer name
    email: Maintainer email
servers:
  - url: counting-backend.example.com
paths:
  /counter/next:
    get:
      summary: get next number
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/CounterNextResponse'

components:
  schemas:
    CounterNextResponse:
      type: object
      properties:
        number:
          type: integer
      required:
        - number

Now run command to apply changed schema:

mify generate counting-backend

caution

If you remove or change the name of the handler after you ran mify generate you need to delete directory with generated files and then re-run mify generate command.

Directory with generated files is located in go-services/internal/counting-backend/generated.

Now we have our handler and we are ready to implement the logic.