英文:
Golang Build Constraints Random
问题
我有两个带有不同构建约束的go文件。
constants_production.go:
// +build production,!staging
package main
const (
URL = "production"
)
constants_staging.go:
// +build staging,!production
package main
const (
URL = "staging"
)
main.go:
package main
func main() {
fmt.Println(URL)
}
当我执行go install -tags "staging"时，有时会打印production，有时会打印staging。同样，当我执行go install -tags "production"时，...
如何在每次构建时获得一致的输出？当我指定staging作为构建标志时，如何使其打印staging？当我指定production作为构建标志时，如何使其打印production？我在这里做错了什么吗？
英文:
I have two go files with different build constraints in the header.
constants_production.go:
// +build production,!staging
package main
const (
URL = "production"
)
constants_staging.go:
// +build staging,!production
package main
const (
URL = "staging"
)
main.go:
package main
func main() {
fmt.Println(URL)
}
When I do a go install -tags "staging", sometimes, it prints production; Sometimes, it prints staging. Similarly, when I do go install -tags "production",...
How do I get a consistent output on every build? How do I make it print staging when I specify staging as a build flag? How do I make it print production when I specify production as a build flag? Am I doing something wrong here?
答案1
得分: 7
go build和go install在看起来没有任何更改的情况下不会重新构建包（二进制文件），并且不会对命令行构建标签的更改敏感。
一种查看此情况的方法是添加-v以打印构建的包：
$ go install -v -tags "staging"
my/server
$ go install -v -tags "production"
（没有输出）
您可以通过添加-a标志来强制重新构建，但这可能有点过度：
$ go install -a -v -tags "production"
my/server
...或者在构建之前触摸服务器源文件：
$ touch main.go
$ go install -a -tags "staging"
...或者在构建之前手动删除二进制文件：
$ rm .../bin/server
$ go install -a -tags "production"
英文:
go build and go install will not rebuild the package (binary) if it looks like nothing has changed -- and it's not sensitive to changes in command-line build tags.
One way to see this is to add -v to print the packages as they are built:
$ go install -v -tags "staging"
my/server
$ go install -v -tags "production"
(no output)
You can force a rebuild by adding the -a flag, which tends to be overkill:
$ go install -a -v -tags "production"
my/server
...or by touching a server source file before the build:
$ touch main.go
$ go install -a -tags "staging"
...or manually remove the binary before the build:
$ rm .../bin/server
$ go install -a -tags "production"
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