.PHONY: all clean images
.DEFAULT_GOAL := all

# Boiler plate for bulding Docker containers.
# All this must go at top of file I'm afraid.
IMAGE_PREFIX := quay.io/weaveworks/build-
IMAGE_TAG := $(shell ../image-tag)
GIT_REVISION := $(shell git rev-parse HEAD)
UPTODATE := .uptodate

# Every directory with a Dockerfile in it builds an image called
# $(IMAGE_PREFIX)<dirname>. Dependencies (i.e. things that go in the image)
# still need to be explicitly declared.
%/$(UPTODATE): %/Dockerfile %/*
	$(SUDO) docker build --build-arg=revision=$(GIT_REVISION) -t $(IMAGE_PREFIX)$(shell basename $(@D)) $(@D)/
	$(SUDO) docker tag $(IMAGE_PREFIX)$(shell basename $(@D)) $(IMAGE_PREFIX)$(shell basename $(@D)):$(IMAGE_TAG)
	touch $@

# Get a list of directories containing Dockerfiles
DOCKERFILES := $(shell find . -name tools -prune -o -name vendor -prune -o -type f -name 'Dockerfile' -print)
UPTODATE_FILES := $(patsubst %/Dockerfile,%/$(UPTODATE),$(DOCKERFILES))
DOCKER_IMAGE_DIRS := $(patsubst %/Dockerfile,%,$(DOCKERFILES))
IMAGE_NAMES := $(foreach dir,$(DOCKER_IMAGE_DIRS),$(patsubst %,$(IMAGE_PREFIX)%,$(shell basename $(dir))))
images:
	$(info $(IMAGE_NAMES))
	@echo > /dev/null

# Define imagetag-golang, etc, for each image, which parses the dockerfile and
# prints an image tag. For example:
#     FROM golang:1.8.1-stretch
# in the "foo/Dockerfile" becomes:
#     $ make imagetag-foo
#     1.8.1-stretch
define imagetag_dep
.PHONY: imagetag-$(1)
$(patsubst $(IMAGE_PREFIX)%,imagetag-%,$(1)): $(patsubst $(IMAGE_PREFIX)%,%,$(1))/Dockerfile
	@cat $$< | grep "^FROM " | head -n1 | sed 's/FROM \(.*\):\(.*\)/\2/'
endef
$(foreach image, $(IMAGE_NAMES), $(eval $(call imagetag_dep, $(image))))

all: $(UPTODATE_FILES)

clean:
	$(SUDO) docker rmi $(IMAGE_NAMES) >/dev/null 2>&1 || true
	rm -rf $(UPTODATE_FILES)