chris001177

package main

import (
	"net/http"
	"time"
)

// As noted above, since we plan to only have one instance
// for those 3 services, we'll declare a singleton instance,
// and make sure we only use them to access those services.

chris001177

package main

// We use interfaces as the types of our database instances
// to make it possible to write tests and use mock implementations.
type userDB interface {
    userRoleByID(id string) string
}

// Note the naming `someConfigDB`. In actual cases we use
// some DB implementation and name our structs accordingly.

chris001177

package main

import (
	"fmt"
	"net/http"
	"strings"
)

func UserPermissionsByID(w http.ResponseWriter, r *http.Request) {
	id := r.URL.Query()["id"][0]

chris001177

package main

// Note how the main package is the only one importing
// packages other than the definition package.
import (
    "github.com/myproject/config"
    "github.com/myproject/database"
    "github.com/myproject/definition"
    "github.com/myproject/handler"
    "net/http"

chris001177

package definition

// Note that in this approach both the singleton instance
// and its interface type are declared in the definition
// package. Make sure this package does not contain any
// logic, otherwise it might need to import other packages
// and its neutral nature is compromised.
var (
    UserDBInstance   UserDB
    ConfigDBInstance ConfigDB

chris001177

package definition

var RolePermissions map[string][]string

chris001177

package database

type SomeUserDB struct{}

func (db *SomeUserDB) UserRoleByID(id string) string {
    // implementation
}

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package database

type SomeConfigDB struct{}

func (db *SomeConfigDB) AllPermissions() map[string][]string {
    // implementation
}

chris001177

package config

import (
    "github.com/myproject/definition"
    "time"
)

// Since the definition package must not contain any logic,
// managing configuration is implemented in a config package.
func InitPermissions() {

chris001177

package handler

import (
    "fmt"
    "github.com/myproject/definition"
    "net/http"
    "strings"
)

func UserPermissionsByID(w http.ResponseWriter, r *http.Request) {