英文:
Settings global conditional variables in Go
问题
我想在Go的全局包级别上根据环境变量的值来解析和设置一个变量，这样我就不必每次在实用函数中检查它（因为变量只需在运行时声明一次）。例如，我想要实现的是（Go伪代码）：
import (
"fmt"
"os"
"strconv"
)
// 这段代码可以读取MYVAR的值（true/false）
var myvar string = os.Getenv("MYVAR")
// 显然这对于Go来说太多了
var myvarbool, _ = strconv.ParseBool(myvar)
// 检查值的实用函数
func mycheck() {
if myvarbool {
fmt.Print("MYVAR is true")
}
}
这是一个库包，所以没有main()函数来进行此类设置，但我希望能够在库中的其他函数中使用mycheck()，而不必每次调用mycheck()时都读取和解析MYVAR。
英文:
I want to parse and set a variable conditionally in Go at the global package level based on the value of of an ENV var, so that I don't have to check for it every time in a utility function (as the variable would be declared once at run time). For example, what I want to accomplish is (Go pseudo-code):
import (
"fmt"
"os"
"strconv"
)
// This works to read the value of MYVAR (=true/false)
var myvar string = os.Getenv("MYVAR")
// Apparently this is too much for Go
var myvarbool, _ = strconv.ParseBool(myvar)
// Utility function to check for value
func mycheck() {
if myvarbool {
fmt.Print("MYVAR is true")
}
}
This is a library package, so doesn't have a main() function to do this kind of setup, but I want to be able to use mycheck() in other functions in the library, and don't want to have to read and parse MYVAR every time mycheck() is called.
答案1
得分: 6
你要翻译的内容如下：
要实现你想要做的事情，一种方法是在init()函数中处理环境变量，所以以下代码可以实现：
package main
import (
"fmt"
"os"
"strconv"
)
var (
myvar string = os.Getenv("MYVAR")
myvarbool bool
)
func init() {
myvarbool, _ = strconv.ParseBool(myvar)
}
// 检查值的实用函数
func mycheck() {
if myvarbool {
fmt.Print("MYVAR is true")
}
}
英文:
One way to accomplish what you're looking to do would be to process the environment variable in an init() function, so something like the following would work:
package main
import (
"fmt"
"os"
"strconv"
)
var (
myvar string = os.Getenv("MYVAR")
myvarbool bool
)
func init() {
myvarbool, _ = strconv.ParseBool(myvar)
}
// Utility function to check for value
func mycheck() {
if myvarbool {
fmt.Print("MYVAR is true")
}
}
答案2
得分: 4
我不确定你遇到了什么问题，你在原始帖子中的代码是有效的，你也可以将其写成一行，像这样：
var myvarbool, _ = strconv.ParseBool(os.Getenv("MYVAR"))
英文:
I'm not sure what problem you had, your code from the OP is valid, also you can have it in one line like:
var myvarbool, _ = strconv.ParseBool(os.Getenv("MYVAR"))
<kbd>playground</kbd>
答案3
得分: 0
在经过几分钟的思考后，我意识到我可以创建一个包装函数来完成这个工作，并调用该函数（再次强调，以下是伪代码，没有额外的检查）：
var myenvbool bool = myenv("MYVAR")
func myenv(envvar string) bool {
myenvvalue := os.Getenv(envvar)
myenvbool, _ := strconv.ParseBool(myenvvalue)
return myenvbool
}
func checkenv() {
if myenvbool {
fmt.Print("myenvbool is true")
}
}
英文:
After actually thinking about this for a couple of minutes, I've realised I can just create a wrapper function to do the work, and call that instead (again, largely pseudo-code without extra checks):
var myenvbool bool = myenv("MYVAR")
func myenv(envvar string) bool {
myenvvalue := os.Getenv(envvar)
myenvbool, _ := strconv.ParseBool(myenvvalue)
return myenvbool
}
func checkenv() {
if myenvbool {
fmt.Print("myenvbool is true")
}
}
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