Can i have custom build flags like os/arch comment directives

Question

In golang I am able to set compiler directives in the first line comment of a file to determine whether the code on that file is included in the build based on OS or arch, e.g

to target windows:

// +build windows

or non-windows:

// +build !windows

Is there any way to pass in my own boolean variable at build time to operate in the same way?

The background is that I would like a boolean debug flag which I can pass in to do a debug build, I don't want my debug code included in the normal build.

I currently do something like this:

go build -ldflags "-X main.Debug=true"

but I would prefer to use 1st line comment method particularly as this approach doesn't omit debug code from the build (I presume).

Ideally I want:

debug-on.go

// +build debug

package debug

func Debug() bool {
    return true
}

and debug-off.go

// +build !debug

package debug

func Debug() bool {
    return false
}

Update RE duplicate I accept the related question has the same subject matter but it's really not a duplicate question, that is a question from somebody who already knew about this feature but is struggling with implementation.

My 2 cents is that it seems the equivalent of "What language to people speak in France?" vs "How do you say 'This is not a duplicate' in French?"

Possible duplicate of [Golang conditional compilation](https://stackoverflow.com/questions/10646531/golang-conditional-compilation) — Adrian, Nov 13 '17 at 14:54
@Adrian: Different question, different answer. The answer to the [Golang conditional compilation](https://stackoverflow.com/questions/10646531) question was to add a blank line following build contraints. That's not an answer to this question. — peterSO, Nov 14 '17 at 00:23
@Adrian: The official words: "That's because the proof is in the answers. If the question looks the same, but the answers aren't solving the asker's problem, that is not a dupe – that is a legitimate new question." — peterSO, Nov 14 '17 at 00:50
@peterso It demonstrates how to use build tags, which is the answer to this question. You're welcome to find a more appropriate duplicate. — Adrian, Nov 14 '17 at 03:42

peterSO · Accepted Answer · 2017-11-13T00:25:53.807

Command go

Go is a tool for managing Go source code.

Usage:
go command [arguments]
Compile packages and dependencies

Usage:
go build [-o output] [-i] [build flags] [packages]
Build compiles the packages named by the import paths, along with their dependencies, but it does not install the results.

The build flags are shared by the build, clean, get, install, list, run, and test commands:
-tags 'tag list'
  a space-separated list of build tags to consider satisfied during the
  build. For more information about build tags, see the description of
  build constraints in the documentation for the `go/build` package.

go/build package: Build Constraints

For example, in source,

// +build debug

At runtime, for build, clean, get, install, list, run, and test go commands,

$ go install -tags='debug'

Can i have custom build flags like os/arch comment directives

1 Answers1