dpyoh6553 2018-01-01 10:32
浏览 69
已采纳

如何在Golang Google数据存储包中正确使用上下文?

I've started using Google Cloud Datastore in one of the project in the company I currently work in.

https://godoc.org/cloud.google.com/go/datastore

In the provided example, they use a context and pass it to the connection instance

ctx := context.Background()
dsClient, err := datastore.NewClient(ctx, "my-project")

Through the documentation you will see that they pass a context to all the functions that makes operations on the database, I am not sure if they are passing the same pointer or create a new pointer for each operation.

The current setup that I have is a global variable for the context in a package called "store" which I keep all the structs functions that communicate with the db, and I use that global variable each time. I don't know what is the effect of that, I am not sure why the context is used, Should I get reference of context.Background() each time I make operations on the database ?

  • 写回答

1条回答 默认 最新

  • doucan957495 2018-01-02 06:53
    关注

    context.Background is the global context--so no need for you global variable. Most of the time you'll want to use a child of that context, with a cancel or a timeout.

    ctx, cancel := context.WithCancel(context.Background)
    //or
    ctx, cancel := context.WithTimeout(context.Background, time.Second * 30) 
    

    Then you can use the cancel function to close down your application nicely, or cancel and retry if a request is hanging. If you never plan on canceling or timing out operations, then using context.Background is fine.

    Also context.Context is an interface so it's always passed by reference, so all uses of a certain instance point to the same context.

    本回答被题主选为最佳回答 , 对您是否有帮助呢?
    评论

报告相同问题?

悬赏问题

  • ¥15 宇视监控服务器无法登录
  • ¥15 PADS Logic 原理图
  • ¥15 PADS Logic 图标
  • ¥15 电脑和power bi环境都是英文如何将日期层次结构转换成英文
  • ¥15 DruidDataSource一直closing
  • ¥20 气象站点数据求取中~
  • ¥15 如何获取APP内弹出的网址链接
  • ¥15 wifi 图标不见了 不知道怎么办 上不了网 变成小地球了
  • ¥50 STM32单片机传感器读取错误
  • ¥50 power BI 从Mysql服务器导入数据,但连接进去后显示表无数据