[Makefile with Build-In-Help]help and also git tag, git commit hash, and build time injection into binary #make

makefile-with-build-in-help.mk

# Makefile to build ...
#
# for help run: make help
# nicer output with: make help | bat -l mk
#
# an alternative for build-in help w/ color coding and w/o .PHONY:
# https://github.com/Byron/dua-cli/blob/d0e85fec1586a8937928472e361837ef21e40b14/Makefile
#
BINARY=$(shell basename $(shell pwd))
VERSION=$(shell git describe --tags --dirty)

# Get name of Makefile so the grep picks the right one
name1 := $(lastword $(MAKEFILE_LIST))

# Set help as the default goal
.DEFAULT_GOAL := help

help:
	@echo "$(BINARY) $(VERSION) $(shell git rev-parse HEAD)"
	@echo
	@grep '^.PHONY: .* #' "$(name1)" | sed 's/\.PHONY: \(.*\) # \(.*\)/\1: \2/' | expand -t20
	@echo

.PHONY: build # build binary on current platform
build:
	go build -o $(BINARY) -ldflags '-extldflags "-static"' -ldflags "-X main.Buildstamp=`date -u '+%Y-%m-%d_%I:%M:%S%p'` -X main.Githash=`git rev-parse HEAD` -X main.Version=$(VERSION)" .

.PHONY: buildLinux # build binary for Linux and enforce rebuild of packages that are already up-to-date (-a); takes longer
buildLinux:
	env CGO_ENABLED=0 GOOS=linux GOARCH=amd64 GOGC=off go build -o $(BINARY) -a -ldflags '-extldflags "-static"' -ldflags "-X main.Buildstamp=`date -u '+%Y-%m-%d_%I:%M:%S%p'` -X main.Githash=`git rev-parse HEAD` -X main.Version=`$(VERSION)`" .

.PHONY: lint # lint the code
lint:
	golangci-lint run --sort-results

.PHONY: tidy # tidy up the GO build environment
tidy:
	go mod tidy -compat=1.20

.PHONY: update # update the GO dependencies
update:
	go get -u all

.PHONY: currentTag # get the tag that will be used for current binary
currentTag:
	@echo "$(VERSION)"