1. Install the gopkg.in/mgo.v2, gopkg.in/mgo.v2/bson, and github.com/gorilla/mux packages, using the go get command, as follows:

$ go get gopkg.in/mgo.v2
$ go get gopkg.in/mgo.v2/bson
$ go get github.com/gorilla/mux

2. Create read-record-mongodb.go. Then we connect to the MongoDB database, read all the documents from an employee collection, marshal the list to JSON, and write it to an HTTP response stream, as follows:

package main
import 
(
  "encoding/json"
  "log"
  "net/http"
  "github.com/gorilla/mux"
  mgo "gopkg.in/mgo.v2"
  "gopkg.in/mgo.v2/bson"
)
const 
(
  CONN_HOST = "localhost"
  CONN_PORT = "8080"
  MONGO_DB_URL = "127.0.0.1"
)
var session *mgo.Session
var connectionError error
func init() 
{
  session, connectionError = mgo.Dial(MONGO_DB_URL)
  if connectionError != nil 
  {
    log.Fatal("error connecting to database :: ", connectionError)
  }
  session.SetMode(mgo.Monotonic, true)
}
type Employee struct 
{
  Id int `json:"uid"`
  Name string `json:"name"`
}
func readDocuments(w http.ResponseWriter, r *http.Request) 
{
  log.Print("reading documents from database")
  var employees []Employee
  collection := session.DB("mydb").C("employee")
  err := collection.Find(bson.M{}).All(&employees)
  if err != nil 
  {
    log.Print("error occurred while reading documents from 
    database :: ", err)
    return
  }
  json.NewEncoder(w).Encode(employees)
}
func main() 
{
  router := mux.NewRouter()
  router.HandleFunc("/employees", readDocuments).Methods("GET")
  defer session.Close()
  err := http.ListenAndServe(CONN_HOST+":"+CONN_PORT, router)
  if err != nil 
  {
    log.Fatal("error starting http server :: ", err)
    return
  }
}

3. Run the program with the following command: 

$ go run read-record-mongodb.go