Setting up go-swagger in an existing project to generate API docs

[sakshak (Sakib)]

I have an existing project that needs a UI for the API. I want to use go swagger but I am completely confused https://github.com/go-swagger/go-swagger/tree/master/examples/todo-list
I want to set it up so I add annotations in the code and then run the command swagger generate spec and it would generate the spec
However whenever I run it, it prints {"swagger":"2.0","paths":{},"definitions":{}}
My project structure is as follows

project/ 
  main.go
  api/
    router.go

In main.go I have this annotation

//go:generate swagger generate spec
package main

In router above one of my handlers I have this annotation

// swagger:route GET /profile
//
// Gets profile of user
//
//     Produces:
//     - application/json
//     - application/x-protobuf
//
//     Schemes: http, https, ws, wss
//
//     Security:
//       api_key:
//       oauth: read, write
//
//     Responses:
//       default: genericError
//       200: someResponse
//       422: validationError
r.GET("/profile", profileHandler

I’ve been stuck trying to set up an api generator for a while. Any help is much appreciated. If you have experience setting it up, please let me know how you did it