GNU Make¶

Resources¶

Colored Help¶

Sample Makefile

See origin My Ultimate Makefile for Golang Projects

GREEN  := $(shell tput -Txterm setaf 2)
YELLOW := $(shell tput -Txterm setaf 3)
WHITE  := $(shell tput -Txterm setaf 7)
CYAN   := $(shell tput -Txterm setaf 6)
RESET  := $(shell tput -Txterm sgr0)

all: help

## Build:
build: ## Build your project and put the output binary in out/bin/
    @echo "build target"

clean: ## Remove build related file
    @echo clean target

vendor: ## Copy of all packages needed to support builds and tests in the vendor directory
    @echo vendor target

watch: ## Run the code with cosmtrek/air to have automatic reload on changes
    @echo watch target

## Test:
test: ## Run the tests of the project
    @echo test target

coverage: ## Run the tests of the project and export the coverage
    @echo coverage target

## Docker:
docker-build: ## Use the dockerfile to build the container
    @echo docker-build target

docker-release: ## Release the container with tag latest and version
    @echo docker-release target

## Help:
help: ## Show this help.
    @echo ''
    @echo 'Usage:'
    @echo '  ${YELLOW}make${RESET} ${GREEN}<target>${RESET}'
    @echo ''
    @echo 'Targets:'
    @awk 'BEGIN {FS = ":.*?## "} { \
        if (/^[a-zA-Z_-]+:.*?##.*$$/) {printf "    ${YELLOW}%-20s${GREEN}%s${RESET}\n", $$1, $$2} \
        else if (/^## .*$$/) {printf "  ${CYAN}%s${RESET}\n", substr($$1,4)} \
        }' $(MAKEFILE_LIST)

Functions¶

VERSION  := snapshot
NAME     := myapp_name

# sample make function: $(call fn_build,1:arg,2:arg,3:arg)
define fn_build
@echo arg 1: $(1)
@echo arg 2: $(2)
@echo arg 3: $(3)
endef

.PHONY: build-service
build-service:
    $(call fn_build,$@,$(NAME),$(VERSION))

output

➜ make build-service VERSION=1.0.3
arg 1: build-service
arg 2: myapp_name
arg 3: 1.0.3

Automatic Variables¶

Variable	Details
`$@`	is the file name of the target of the rule
`$<`	is the name of the first prerequisite
`$?`	is the name of all the prerequisites that are newer than the target, with spaces between them. If the target does not exist, all prerequisites will be included
`$^`	is the name of all the prerequisites, with spaces between them

Sample Makefile

main: one two
    @echo '$$@:' $@
    @echo '$$<:' $<
    @echo '$$?:' $?
    @echo '$$^:' $^

    @touch main

one:
    @touch one

two:
    @touch two

clean:
    @rm -f main one two

Output

➜ make main
$@: main
$<: one
$?: one two
$^: one two

# update file "one"
➜ touch one

# output for '$?' has been changed
➜ make main
$@: main
$<: one
$?: one
$^: one two

Loops and Lists¶

List variable in Makefile can be single-line or multi-line (can contain comments).

LIST_MULTILINE += AAA  # Comment 1
LIST_MULTILINE += BBB  # Comment 2
LIST_MULTILINE += CCC  # Comment 3
LIST_MULTILINE += DDD  # Comment 4

# single-line
LIST = Xxx Yyy Zzz

.PHONY: print-list
print-list:
    @for i in $(LIST_MULTILINE); do \
        echo elem: $$i; \
    done
    @echo '-------------'
    @for i in $(LIST); do \
        echo elem: $$i; \
    done

output

➜ make print-list
elem: AAA
elem: BBB
elem: CCC
elem: DDD
-------------
elem: Xxx
elem: Yyy
elem: Zzz