英文:
How to create global variables once when app is launched in Go?
问题
大家好！
我有一个需要密钥进行解密的API服务。每次我发出请求时，密钥都会重新计算。从架构的角度来看，这是错误的。
使用环境变量（.env、viper等）的选项不适用，因为将来我想将这个模块拆分为一个独立的库。
请给我一些建议，如何在启动应用程序时计算密钥，并在停止应用程序之前一直使用它，而不使用环境变量？
英文:
Good day for all readers!
I have api service which needs key for some decrypt issues. Key calculates all time when I make request. That is wrong from an architectural point of view.
The option with environments (.env, viper...) drops because, in the future, I want to bring out this module to a separate library.
Hint me, how it is possible without using environments to calculate the key when starting the application and use it until stopping the application?
答案1
得分: 1
全局变量以大写字母开头，因此可以从其他包中访问。
但是...这实际上是不好的行为，因为其他包可以更改它。
如果使用非大写字母开头的变量，仍然意味着同一包中的函数可以更改它。
也许你可以使用常量？
或者创建一个单例变量，参见：
https://goplay.tools/snippet/9k7FLYbbvoo
英文:
A global var starts with a capital, so it is reachable from within other packages.
But... it's actually bad behaviour, because those other packages can change it.
Having a non capital one, still means that functions in the same package can change it.
Perhaps you can use a constant?
or make a singleton variable, see :
答案2
得分: 0
如果你确定需要一个全局变量，你可以这样做：
package main
var globalVar string = "My string"
func init(){
globalVar = "The new value of the variable"
}
func main(){
println(globalVar)
}
英文:
If you are sure you need a global variable, you can do this:
package main
var globalVar string = "My string"
func init(){
globalVar = "The new value of the variable"
}
func main(){
println(globalVar)
}
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