[BUILD] Make docker-image building more reliable

We need to create a tighter coupling between the build
system and the resulting docker images to prevent
make from over-optimizing steps away.

Fixes FAB-1145

Change-Id: I50c7cdf98e173c88ff6722d6c28aeade7395428e
Signed-off-by: Greg Haskins <gregory.haskins@gmail.com>

Makefile

@@ -89,20 +89,20 @@ membersrvc-image:
 
 .PHONY: peer
 peer: build/bin/peer
-peer-docker: build/image/peer/.dummy
+peer-docker: build/image/peer/$(DUMMY)
 
 .PHONY: orderer
 orderer: build/bin/orderer
-orderer-docker: build/image/orderer/.dummy
+orderer-docker: build/image/orderer/$(DUMMY)
 
-testenv: build/image/testenv/.dummy
+testenv: build/image/testenv/$(DUMMY)
 
 unit-test: peer-docker testenv
 	cd unit-test && docker-compose up --abort-on-container-exit --force-recreate && docker-compose down
 
 unit-tests: unit-test
 
-docker: $(patsubst %,build/image/%/.dummy, $(IMAGES))
+docker: $(patsubst %,build/image/%/$(DUMMY), $(IMAGES))
 native: peer orderer
 
 behave-deps: docker peer build/bin/block-listener
@@ -152,12 +152,12 @@ build/docker/busybox:
 		make -f busybox/Makefile install BINDIR=$(@D)
 
 # Both peer and peer-docker depend on ccenv and javaenv (all docker env images it supports).
-build/bin/peer: build/image/ccenv/.dummy build/image/javaenv/.dummy
-build/image/peer/.dummy: build/image/ccenv/.dummy build/image/javaenv/.dummy
+build/bin/peer: build/image/ccenv/$(DUMMY) build/image/javaenv/$(DUMMY)
+build/image/peer/$(DUMMY): build/image/ccenv/$(DUMMY) build/image/javaenv/$(DUMMY)
 
 # Both peer-docker and orderer-docker depend on the runtime image
-build/image/peer/.dummy: build/image/runtime/.dummy
-build/image/orderer/.dummy: build/image/runtime/.dummy
+build/image/peer/$(DUMMY): build/image/runtime/$(DUMMY)
+build/image/orderer/$(DUMMY): build/image/runtime/$(DUMMY)
 
 build/bin/%: $(PROJECT_FILES)
 	@mkdir -p $(@D)
@@ -185,8 +185,8 @@ build/image/%/payload:
 	mkdir -p $@
 	cp $^ $@
 
-build/image/%/.dummy: Makefile build/image/%/payload
-	$(eval TARGET = ${patsubst build/image/%/.dummy,%,${@}})
+build/image/%/$(DUMMY): Makefile build/image/%/payload
+	$(eval TARGET = ${patsubst build/image/%/$(DUMMY),%,${@}})
 	@echo "Building docker $(TARGET)-image"
 	@cat images/$(TARGET)/Dockerfile.in \
 		| sed -e 's/_BASE_TAG_/$(BASE_DOCKER_TAG)/g' \

docker-env.mk

@@ -56,5 +56,32 @@ BASE_DOCKER_TAG=$(ARCH)-$(BASEIMAGE_RELEASE)
 DOCKER_GO_LDFLAGS += $(GO_LDFLAGS)
 DOCKER_GO_LDFLAGS += -linkmode external -extldflags '-static -lpthread'
 
+#
+# What is a .dummy file?
+#
+# Make is designed to work with files.  It uses the presence (or lack thereof)
+# and timestamps of files when deciding if a given target needs to be rebuilt.
+# Docker containers throw a wrench into the works because the output of docker
+# builds do not translate into standard files that makefile rules can evaluate.
+# Therefore, we have to fake it.  We do this by constructioning our rules such
+# as
+#       my-docker-target/.dummy:
+#              docker build ...
+#              touch $@
+#
+# If the docker-build succeeds, the touch operation creates/updates the .dummy
+# file.  If it fails, the touch command never runs.  This means the .dummy
+# file follows relatively 1:1 with the underlying container.
+#
+# This isn't perfect, however.  For instance, someone could delete a docker
+# container using docker-rmi outside of the build, and make would be fooled
+# into thinking the dependency is statisfied when it really isn't.  This is
+# our closest approximation we can come up with.
+#
+# As an aside, also note that we incorporate the version number in the .dummy
+# file to differentiate different tags to fix FAB-1145
+#
+DUMMY = .dummy-$(DOCKER_TAG)
+