英文:
Best Practise opening DB
问题
注意：我不确定这是否是这篇文章的最准确的标题，如果不是，请提供一个更好的标题。
目前，我正在创建一个服务器，其中包含几个处理程序（使用goji）。在接收到请求后，我想要与我拥有的MongoDB数据库进行交互（使用mgo）。我的问题是：
我假设每次处理请求时执行这种操作是昂贵的：
uri := os.Getenv("MONGOHQ_URL")if uri == "" {panic("no DB connection string provided")}session, err := mgo.Dial(uri)
那么，对我来说，是否更好的做法是拥有一个可以从处理程序内部访问的全局变量呢？ 所以我会这样做：
var session *mgo.Sessionfunc main() {session = setupDB()defer session.Close()goji.Get("/user", getUser)goji.Serve()}func getUser(c web.C, w http.ResponseWriter, r *http.Request) {// 在这里使用 session 变量}
我的问题与在这里应该采用什么最佳实践有关？是每次请求到来时打开数据库，还是在整个应用程序的生命周期内保持数据库连接打开？
英文:
Note: I am not sure if this is the most accurate title for this post, if not, please advise on a better one.
Currently I am creating a server where I have a couple of handlers (using goji). After receiving a request, I want to interact with a MongoDB database I have (using mgo). My question is:
I am assuming doing this kind of stuff every time I am handling a request is expensive:
uri := os.Getenv("MONGOHQ_URL")if uri == "" {panic("no DB connection string provided")}session, err := mgo.Dial(uri)
So, would it be better for me to have a global var that I can access from inside the handlers? So I would go with something like this:
var session *mgo.Sessionfunc main() {session = setupDB()defer session.Close()goji.Get("/user", getUser)goji.Serve()}func getUser(c web.C, w http.ResponseWriter, r *http.Request) {// Use the session var here}
My question is related to what would be the best practise here? Opening the DB every time a request comes in, or keep it open for the entire duration of the application.
答案1
得分: 1
你可以像这样将你的处理程序包装在一个Controller结构体中：（http://play.golang.org/p/NK6GO_lqgk）
package mainimport ("fmt""log""net/http""os""github.com/zenazn/goji""github.com/zenazn/goji/web")type Controller struct {session *Session}func NewController() (*Controller, error) {if uri := os.Getenv("MONGOHQ_URL"); uri == "" {return nil, fmt.Errorf("no DB connection string provided")}session, err := mgo.Dial(uri)if err != nil {return nil, err}return &Controller{session: session,}, nil}func (c *Controller) getUser(c web.C, w http.ResponseWriter, r *http.Request) {// 在这里使用session变量}func main() {ctl, err := NewController()if err != nil {log.Fatal(err)}defer ctl.session.Close()goji.Get("/user", ctl.getUser)goji.Serve()}这样，你可以将session嵌入到处理程序中，并添加任何其他你可能需要的数据。<details><summary>英文:</summary>What about wraping your handler in a Controller struct like this: (http://play.golang.org/p/NK6GO_lqgk)package mainimport ("fmt""log""net/http""os""github.com/zenazn/goji""github.com/zenazn/goji/web")type Controller struct {session *Session}func NewController() (*Controller, error) {if uri := os.Getenv("MONGOHQ_URL"); uri == "" {return nil, fmt.Errorf("no DB connection string provided")}session, err := mgo.Dial(uri)if err != nil {return nil, err}return &Controller{session: session,}, nil}func (c *Controller) getUser(c web.C, w http.ResponseWriter, r *http.Request) {// Use the session var here}func main() {ctl, err := NewController()if err != nil {log.Fatal(err)}defer ctl.session.Close()goji.Get("/user", ctl.getUser)goji.Serve()}This way, you can embed your session in your handler and add any other data that you might need.</details>
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