Clarification: docker build will use system's arch, not always amd64

Author: consideRatio

Makefile

@@ -49,12 +49,13 @@ help:
 
 
 build/%: DARGS?=
-build/%: ## build the latest image for a stack on amd64 only
-	@echo "::group::Build $(OWNER)/$(notdir $@) (amd64)"
+build/%: ## build the latest image for a stack using the system's architecture
+	@echo "::group::Build $(OWNER)/$(notdir $@) (system's architecture)"
+	docker build $(DARGS) --rm --force-rm -t $(OWNER)/$(notdir $@):latest ./$(notdir $@) --build-arg OWNER=$(OWNER)
 	docker build $(DARGS) --rm --force-rm -t $(OWNER)/$(notdir $@):latest ./$(notdir $@) --build-arg OWNER=$(OWNER)
 	@echo -n "Built image size: "
 	@docker images $(OWNER)/$(notdir $@):latest --format "{{.Size}}"
-	@echo "::endgroup::Build $(OWNER)/$(notdir $@) (amd64)"
+	@echo "::endgroup::Build $(OWNER)/$(notdir $@) (system's architecture)"
 build-all: $(foreach I,$(ALL_IMAGES), build/$(I) ) ## build all stacks
 
 # Limitations on docker buildx build (using docker/buildx 0.5.1):
@@ -70,8 +71,9 @@ build-all: $(foreach I,$(ALL_IMAGES), build/$(I) ) ## build all stacks
 #
 # Workarounds due to limitations:
 #
-# 1. We always make a dedicated amd64 build named as OWNER/<stack>-notebook so
-#    we always can reference that image no matter what.
+# 1. We always build a dedicated image using the current system architecture
+#    named as OWNER/<stack>-notebook so we always can reference that image no
+#    matter what during tests etc.
 #
 # 2. We always also build a multi-platform image during build-multi that will be
 #    inaccessible with `docker tag` and `docker push` etc, but this will help us
@@ -80,7 +82,8 @@ build-all: $(foreach I,$(ALL_IMAGES), build/$(I) ) ## build all stacks
 #
 # 3. We let push-multi refer to rebuilding a multi image with `--push`.
 #
-#    We now rely on the cached layer.
+#    We can rely on the cached layer from build-multi now even though we never
+#    tagged the multi image.
 #
 # Outcomes of the workaround:
 #
@@ -91,13 +94,17 @@ build-all: $(foreach I,$(ALL_IMAGES), build/$(I) ) ## build all stacks
 #    architectures as well, then we can build and publish such images via the
 #    `-multi` suffix without needing a local registry.
 #
+# 3. If we get dedicated arm64 runners, we can test everything separately
+#    without needing to update this Makefile, and if all tests succeeds we can
+#    do a publish job that creates a multi-platform image for us.
+#
 build-multi/%: DARGS?=
-build-multi/%: ## build the latest image for a stack on amd64 and arm64
-	@echo "::group::Build $(OWNER)/$(notdir $@) (amd64)"
-	docker buildx build $(DARGS) --rm --force-rm -t $(OWNER)$(notdir $@):latest ./$(notdir $@) --build-arg OWNER=$(OWNER) --platform "linux/amd64" --load
+build-multi/%: ## build the latest image for a stack on both amd64 and arm64
+	@echo "::group::Build $(OWNER)/$(notdir $@) (system's architecture)"
+	docker buildx build $(DARGS) --rm --force-rm -t $(OWNER)/$(notdir $@):latest ./$(notdir $@) --build-arg OWNER=$(OWNER)
 	@echo -n "Built image size: "
 	@docker images $(OWNER)/$(notdir $@):latest --format "{{.Size}}"
-	@echo "::endgroup::Build $(OWNER)/$(notdir $@) (amd64)"
+	@echo "::endgroup::Build $(OWNER)/$(notdir $@) (system's architecture)"
 
 	@echo "::group::Build $(OWNER)/$(notdir $@) (amd64,arm64)"
 	docker buildx build $(DARGS) --rm --force-rm -t build-multi-tmp-cache/$(notdir $@):latest ./$(notdir $@) --build-arg OWNER=$(OWNER) --platform "linux/amd64,linux/arm64"
@@ -174,9 +181,9 @@ pull-all: $(foreach I,$(ALL_IMAGES),pull/$(I)) ## pull all images
 
 push/%: DARGS?=
 push/%: ## push all tags for a jupyter image
-	@echo "::group::Push $(OWNER)/$(notdir $@) (amd64)"
+	@echo "::group::Push $(OWNER)/$(notdir $@) (system's architecture)"
 	docker push --all-tags $(DARGS) $(OWNER)/$(notdir $@)
-	@echo "::endgroup::Push $(OWNER)/$(notdir $@) (amd64)"
+	@echo "::endgroup::Push $(OWNER)/$(notdir $@) (system's architecture)"
 push-all: $(foreach I,$(ALL_IMAGES),push/$(I) ) ## push all tagged images
 
 push-multi/%: DARGS?=