Makefile that generates version.json from git

Makefile

# get version info from git (look for tag like 'v1.0')
GIT_VERSION = $(shell git describe --match "v[0-9]*")
GIT_BUILD = $(shell git describe --match "v[0-9]*" --long --dirty)
GIT_COMMIT = $(shell git rev-parse --short HEAD)
GIT_COMMIT_LONG = $(shell git rev-parse HEAD)

define VERSION_BODY
# this file generated by build process
{
  "version": "${GIT_VERSION}",
  "build": "${GIT_BUILD}",
  "commit": "${GIT_COMMIT}",
  "commit_long": "${GIT_COMMIT_LONG}"
}
endef
export VERSION_BODY

version.json:
        echo "$$VERSION_BODY" > $@