Makefile

# Load the latest tag, and set a default for TAG. The goal here is
# to ensure TAG is set as early possible, considering it's usually
# provided as an input anyway, but we want running "make" to
# *just work*.

include latest.mk

ifndef LATEST_TAG
$(error LATEST_TAG *must* be set in latest.mk)
endif

ifeq "$(TAG)" "latest"
override TAG = $(LATEST_TAG)
endif

TAG ?= $(LATEST_TAG)


# Import configuration. config.mk must set the variables REGISTRY
# and REPOSITORY so the Makefile knows what to call your image.
# You can also set PUSH_REGISTRIES and PUSH_TAGS to customize
# what will be pushed.
# Finally, you can set any variable that'll be used by your build
# process, but make sure you export them so they're visible in
# build programs!

include config.mk

ifndef REGISTRY
$(error REGISTRY *must* be set in config.mk)
endif

ifndef REPOSITORY
$(error REPOSITORY *must* be set in config.mk)
endif


# Create $(TAG)/config.mk if you need to e.g. set environment variables depending
# on the tag being built. This is typically useful for things constants like a
# point version, a sha1sum, etc.
# Note that $(TAG)/config.mk is entirely optional.

-include $(TAG)/config.mk


# By default, we'll push the tag we're building, and the 'latest' tag if said
# tag is indeed the latest one. Set PUSH_TAGS in config.mk (or $(TAG)/config.mk)
# to override that behavior (note: you can't override the 'latest' tag).

PUSH_TAGS ?= $(TAG)

ifeq "$(TAG)" "$(LATEST_TAG)"
PUSH_TAGS += latest
endif


# By default, we'll push the registry we're naming the image after. You can
# override this in config.mk (or $(TAG)/config.mk)

PUSH_REGISTRIES ?= $(REGISTRY)


# Export what we're building for e.g. test scripts to use. Exporting
# other variables is the responsibility of config.mk and $(TAG)/config.mk.

export REGISTRY
export REPOSITORY
export TAG


# Define actual usable targets

# TODO - Should push depend on test instead? Ideally push is only going to be used by CI anyway.
push: build
	set -e ; \
	for registry in $(PUSH_REGISTRIES); do \
		for tag in $(PUSH_TAGS); do \
			docker tag "$(REGISTRY)/$(REPOSITORY):$(TAG)" "$${registry}/$(REPOSITORY):$${tag}"; \
			docker push "$${registry}/$(REPOSITORY):$${tag}"; \
		done \
	done


test: build
	set -e ; if [ -f 'test.sh' ]; then ./test.sh; break; fi


build: $(TAG)/Dockerfile
	docker build -t "$(REGISTRY)/$(REPOSITORY):$(TAG)" -f "$(TAG)/Dockerfile" .
ifeq "$(TAG)" "$(LATEST_TAG)"
	docker tag "$(REGISTRY)/$(REPOSITORY):$(TAG)" "$(REGISTRY)/$(REPOSITORY):latest"
endif


# Per-tag Dockerfile target. Look for Dockerfile or Dockerfile.erb in the root, and use it for $(TAG).
# We prioritize Dockerfile.erb over Dockerfile if both are present.

$(TAG)/Dockerfile: Dockerfile.erb Dockerfile | $(TAG)
	set -e ;\
	if [ -f 'Dockerfile.erb' ]; then \
		erb "Dockerfile.erb" > "$(TAG)/Dockerfile"; \
	else \
		cp "Dockerfile" "$(TAG)/Dockerfile"; \
	fi


# Pseudo targets for Dockerfile and Dockerfile.erb. They don't technically create anything,
# but each warn if the other file is missing (meaning both files are missing).

Dockerfile.erb:
	@ if [ ! -f 'Dockerfile' ]; then echo "You must create one of Dockerfile.erb or Dockerfile"; exit 1; fi

Dockerfile:
	@ if [ ! -f 'Dockerfile.erb' ]; then echo "You must create one of Dockerfile.erb or Dockerfile"; exit 1; fi

$(TAG):
	mkdir -p "$(TAG)"


.PHONY: push test build $(TAG)/Dockerfile
.DEFAULT_GOAL := test