Beginnings of Go web server with mongoDb

I am just learning how to use go and I'm a bit confused on how my code is supposed to be organised package wise.

Am I right to have the user package? I'm planning to redirect my /user/ routes to a handler in this package but I'm unsure if this is the go way to do things

My directory structure is

/go_rest_api
  /user
    -user.go
    -user_provider.go
  -app.go
  -main.go

main.go

package main

func main() {
  a := App{}
  a.Initialize()
  a.Run()
}

app.go

package main

import (
  "fmt"
  "log"
  "github.com/gorilla/mux"
  "gopkg.in/mgo.v2"
  "go_rest_api/user"
)

type App struct {
  Router *mux.Router
  Mongo *MongoConnection
}

type MongoConnection struct {
  Session *mgo.Session
}

func(a* App) GetMongoSession() *mgo.Session {
  return a.Mongo.Session.Copy()
}

func(a *App) Initialize() {
  session, err := mgo.Dial("127.0.0.1:27017")
  if err != nil {
    panic(err)
  }

  session.SetMode(mgo.Monotonic, true)

  a.Mongo = &MongoConnection{session}
  a.Router = mux.NewRouter()
}

func(a *App) Run() {
  defer a.Mongo.Session.Close()
  testMongo(a.GetMongoSession())
}

func testMongo(session *mgo.Session) {
  userProvider := user.Provider(session)
  err := userProvider.InsertUser(user.User{"test"})
  if err != nil {
    log.Fatal(err)
  }

  user := user.User{}
  err, user = userProvider.GetUser("test")
  if err != nil {
    log.Fatal(err)
  }

  fmt.Println("username:", user.Username)
}

user/user.go

package user

type User struct {
  Username string
}

user/user_provider.go

```
package user

import (
"gopkg.in/mgo.v2/bson"
"gopkg.in/mgo.v2"
)

type provider struct {
Collection *mgo.Collection
}

func Provider(mongoSession *mgo.Session) provider {
p := provider{}
p.Collection = mongoSession.DB("test").C("user")
return p
}

func(p *provider) InsertUser(user User) error {
return p.Collection.Insert(&user)
}

func (p *provider) GetUser(username string) (error, User) {
result := User{}
err := p.Collection.

You might wanted to start writing some comments on your code.

For example I've read all your code but there are some method that I don't understand like :

func(a* App) GetMongoSession() *mgo.Session {
  return a.Mongo.Session.Copy()
}

Okay we know It is getting the mongo session. but for what purpose?

// We get the mongo session for .... you can start explain why
func(a* App) GetMongoSession() *mgo.Session {
  return a.Mongo.Session.Copy()
}

I think it is a good think to keep comment the code, so others can understand it quickly. especially when someone who new to mongoDB. :D

StackExchange Code Review Q#155587, answer score: 2