How It Works

Mage scans the current directory for go files with the mage build tag (i.e. //go:build mage), using the normal go build rules for following build constraints (aside from requiring the mage tag). It then parses those files to find the build targets, generates a main file for the command, and compiles a binary from those files. The magefiles are hashed so that if they remain unchanged, the same compiled binary will be reused next time, to avoid the generation overhead. As of Mage 1.3.0, the version of Go used to compile the binary is also used in the hash.

Binary Cache

Compiled magefile binaries are stored in $HOME/.magefile. This location can be customized by setting the MAGEFILE_CACHE environment variable.

Go Environment

Mage itself requires no dependencies to run. However, because it is compiling go code, you must have a valid go environment set up on your machine. Mage is compatible with any go 1.7+ environment (earlier versions may work but are not tested).