to compile the API, use the following commands:

$ cd <project-dir>
$ go mod download
$ go build -o gem cmd/gem/main.go

note: this application has been written with go 1.17

to run the application (from the directory where the application has been built):

$ ./gem
# to specify a specific listenning port, use:
$ ./gem -a ip:port

the binary accepts also a [-a] option to specify the address where the embedded HTTP server will listen for incoming requests. The default is to listen on all interface on port 8888

the API, as requested, expose a /productionplan endpoint.

to subscribe to the websocket socket service, you can submit a request to the /ws endpoint.

to execute the test, you can execute in the project directory:

$ go test -v