Enable FETCH_PACKAGES by default

Should speed up most local builds. The theory is that most people
doesn't need to build all packages all the time and for those who
do or are working on a package builds with FETCH_PACKAGES=false.

Since this defaults local changes to packages to NOP add a short
notice every build.

Change-Id: Ib6b6233f23c052b5b88fc2ce309e5e5022f30ca7
diff --git a/Makefile b/Makefile
index fff7a6b..4e0ed5f 100644
--- a/Makefile
+++ b/Makefile
@@ -11,9 +11,9 @@
 	+make -f $(ROOTDIR)/build/Makefile all
 
 out-dirs:
-	mkdir -p $(PRODUCT_OUT)/packages
-	mkdir -p $(PRODUCT_OUT)/obj
-	mkdir -p $(ROOTDIR)/cache
+	@mkdir -p $(PRODUCT_OUT)/packages
+	@mkdir -p $(PRODUCT_OUT)/obj
+	@mkdir -p $(ROOTDIR)/cache
 
 all: boot-targets
 
diff --git a/docker.mk b/docker.mk
index bb60444..e0a15ca 100644
--- a/docker.mk
+++ b/docker.mk
@@ -60,6 +60,7 @@
 		-e "FETCH_PBUILDER_DIRECTORY=/pbuilder" \
 		-e "PACKAGES_FETCH_ROOT_DIRECTORY=/packages" \
 		-e "FETCH_PACKAGES=$(FETCH_PACKAGES)" \
+		-e "PACKAGES_REVISION=$(PACKAGES_REVISION)" \
 		aiy-board-builder \
 		/bin/bash -c \
 			'groupadd --gid $(shell id -g) $(shell id -g -n); \
diff --git a/packages.mk b/packages.mk
index bd475f7..d6d049f 100644
--- a/packages.mk
+++ b/packages.mk
@@ -114,14 +114,18 @@
 
 ALL_PACKAGE_TARGETS := $(foreach package,$(ALL_PACKAGE_NAMES),$(PRODUCT_OUT)/.$(package)) $(PBUILDER_TARGETS)
 packages-tarball: $(ROOTDIR)/cache/packages.tgz
+$(info )
 ifeq ($(FETCH_PACKAGES),true)
-$(ROOTDIR)/cache/packages.tgz: $(PACKAGES_FETCH_ROOT_DIRECTORY)/packages.tgz | out-dirs
+$(info Using prebuilt packages, set FETCH_PACKAGES=false to build locally)
+$(ROOTDIR)/cache/packages.tgz: $(PACKAGES_FETCH_ROOT_DIRECTORY)/$(ROOTFS_REVISION)/packages.tgz | out-dirs
 	cp $< $(ROOTDIR)/cache
 else
+$(info Building packages locally, set FETCH_PACKAGES=true to use prebuilts)
 $(ROOTDIR)/cache/packages.tgz: $(ALL_PACKAGE_TARGETS) | out-dirs
 	$(ROOTDIR)/build/update_packages.sh
 	tar -C $(PRODUCT_OUT) -czf $@ packages
 endif
+$(info )
 
 packages:: $(ALL_PACKAGE_TARGETS)
 
diff --git a/preamble.mk b/preamble.mk
index 171b0e3..067c961 100644
--- a/preamble.mk
+++ b/preamble.mk
@@ -118,5 +118,6 @@
 
 PREBUILT_DOCKER_ROOT ?= /google/data/ro/teams/spacepark/enterprise/kokoro/prod/spacepark/enterprise/docker
 
-FETCH_PACKAGES ?= false
-PACKAGES_FETCH_ROOT_DIRECTORY ?= /google/data/ro/teams/spacepark/enterprise/kokoro/prod/spacepark/enterprise/debcache
+FETCH_PACKAGES ?= true
+PACKAGES_REVISION ?= latest
+PACKAGES_FETCH_ROOT_DIRECTORY ?= /google/data/ro/teams/spacepark/enterprise/kokoro/prod/spacepark/enterprise/continuous