Inject XCADDY_GO_BUILD_FLAGS through go operations (#102)

[aabelix]

Commit 47f9ded is not sufficient alone to
ensure that all go modules are installed with write bit set because 'go mod'
or 'go get' might install submodules of other modules as read-only.

If set, the environment variable appends '-modcacherw' to go mod and go get
to ensure that submodules of other modules have write access.

[aabelix]

Relates to #102 which was not fully resolved, yet.

[mohammed90]

It's best if we don't make super specific flags for the various possible options. According to the go command docs -- emphasis mine:

The build flags are shared by the build, clean, get, install, list, run, and test commands:

The env var introduced earlier is concerned with build flags. What do you think of injecting the provided XCADDY_GO_BUILD_FLAGS across the various commands instead of injecting the -modcacherw as a separate flag? Does this resolve your issue?

[aabelix]

Yes, that will also work. I will amend the change.

[aabelix]

@mohammed90, I think this patch version is better but it does not support build flags to all those commands that you suggested so I think I can improve this a bit. The only common interface that I could find was this

environment.go:

func (env environment) newCommand(command string, args ...string) *exec.Cmd {
	cmd := exec.Command(command, args...)
	cmd.Dir = env.tempFolder
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	return cmd
}

so I could change this interface to append the build flags but I was not sure if you would be OK with it. The name of that method is very generic and it could be potentially used for running other than build-related commands. What do you think?

[aabelix]

I guess this commit would be sufficient as a final solution?

[mohammed90]

@mohammed90, I think this patch version is better but it does not support build flags to all those commands that you suggested so I think I can improve this a bit. The only common interface that I could find was this

environment.go:

func (env environment) newCommand(command string, args ...string) *exec.Cmd {
	cmd := exec.Command(command, args...)
	cmd.Dir = env.tempFolder
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	return cmd
}

so I could change this interface to append the build flags but I was not sure if you would be OK with it. The name of that method is very generic and it could be potentially used for running other than build-related commands. What do you think?

A method like this can guarantee it's only using go command.

func (env environment) newGoCommand(args ...string) *exec.Cmd {
	return env.newCommand(utils.GetGo(), args...)
}

[mohammed90]

Looks good! I'll merge this as-is now, but I'll follow it up with another commit. mod supports modcacherw, modfile, and overlay of the build flags, BUT not the rest. The next commit will add XCADDY_GO_MOD_FLAGS which will only apply to go mod. In your case, you will need to add -modcacherw to both env vars.

Thanks for the work on the PR!

[aabelix]

Sounds good to me. Thank you for your help, Mohammed!