Makefile

GO_SRC = $(wildcard *.go) $(wildcard **/*.go)

define gen-badge
	curl \
		--data-urlencode "label=$(1)" \
		--data-urlencode "message=$(2)" \
		--data-urlencode "color=$(3)" \
		--output "$(4)" \
		https://img.shields.io/static/v1 
endef

define get-color
	if (( `echo "$(1) <= 50" | bc -l` )) ; then \
		echo red ; \
	elif (( $$(echo "$(1) > 80" | bc -l) )) ; then \
		echo green ; \
	else \
		echo orange ; \
	fi
endef

.PHONY: badges test

badges: badges/coverage.svg badges/go-report-card.svg

test:
	$(eval label = Coverage)
	$(eval message = B (16.0%))
	$(eval color = $(shell $(call get-color,20)))
	$(call gen-badge,$(label),$(message),$(color),test.svg)

coverage.out: ${GO_SRC}
	@go test -coverprofile=coverage.out -covermode=count  ./... ;

badges/coverage.svg: coverage.out
	@$(eval coverage = $(shell go tool cover -func=coverage.out \
				| grep total \
				| grep -o '[0-9]\+\.[0-9]\+'))
	@echo coverage: $(coverage)
	$(eval label = Coverage)
	$(eval message = $(coverage)%)
	$(eval color = $(shell $(call get-color,$(coverage))))
	$(call gen-badge,$(label),$(message),$(color),$@)

badges/go-report-card.svg: ${GO_SRC}
	$(eval grade = $(shell grade=$$(goreportcard-cli | head -1); echo $${grade:7}))
	$(eval grade_percent = $(shell echo '$(grade)' | grep -o "[0-9.]\+"))
	@echo 'go report card rating: $(grade)'
	$(eval label = Go Report)
	$(eval message = $(grade))
	$(eval color = $(shell $(call get-color,$(grade_percent))))
	$(call gen-badge,$(label),$(message),$(color),$@)