So, there’s a bootstrap problem with Mage. What if you want to use Mage for
your build, but you need to get it during your CI build? Mage is best built…
with Mage. The problem is that if you don’t use the custom mage install then
Mage isn’t compiled with ldflags that set all the usseful info in mage -version. So what do you do?
Luckily, Mage has a zero install option. You don’t need Mage to
build Mage, there’s a bootstrap file that will let you use go run to install
Mage with all the great version info. The bootstrap.go file in the root of the
repo hooks into mage’s libraries and acts like Mage itself, so you can pass it
mage targets in the current directory.
This will download the mage source and install it (if you’re using a gopath):
go get -d github.com/magefile/mage
go run $GOPATH/src/github.com/magefile/mage/bootstrap.go install
If you’re using go modules, you can do it with good old git clone:
git clone git@github.com:magefile/mage
cd mage
go run bootstrap.go install
Note that in the second case, the binary will be copied to where go env GOPATH points (for now, PRs welcome).