From 7185191736a53773a9dde5ffde7a41af083910db Mon Sep 17 00:00:00 2001
From: Rolf Neugebauer <rolf.neugebauer@docker.com>
Date: Tue, 14 Mar 2017 10:54:01 +0000
Subject: [PATCH] kernel: Add the kernel version to the hub image

A given image is pushed to hub twice, once as
kernel:<kernel version>.<major version>.x and once as
kernel:<kernel version>.<major version>.<minor version>-<n>.

The latter is used to decide if a new kernel image is pushed to hub.

Most users should use the former to pick up the latest kernel.

Signed-off-by: Rolf Neugebauer <rolf.neugebauer@docker.com>
---
 kernel/Makefile | 45 +++++++++++++++++++++++++++++++++------------
 1 file changed, 33 insertions(+), 12 deletions(-)

diff --git a/kernel/Makefile b/kernel/Makefile
index 97d401588..ae500b1a5 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -2,13 +2,34 @@ DEBUG ?= 0
 
 all:	bzImage push
 
+# We push the image to hub twice, once with the full kernel version of
+# "mobylinux/kernel:<kernel version>.<major version>.<minor version>-<n>",
+# where "<n>" is a monotonically increasing config number, and as
+# "mobylinux/kernel:<kernel version>.<major version>.x". This version
+# number is stored in IMAGE_VERSION.
+#
+# We expect most users to us the "<kernel version>.<major version>.x"
+# variant as this simply is the latest version of a given major kernel
+# version. This version number is stored in IMAGE_MAJOR_VERSION.
+#
+# For IMAGE_VERSION, the "<n>" must be increased whenever
+# the kernel config or the patches change. We don't expect this to
+# happen very often as the minor version number gets update quite
+# frequently.
+#
+# IMAGE_VERSION is used to determine if a new image should be pushed to hub.
 ifdef LTS4.4
 KERNEL_VERSION=4.4.53
+IMAGE_VERSION=$(KERNEL_VERSION)-0
+IMAGE_MAJOR_VERSION=4.4.x
 DEPS=Dockerfile.4.4 Makefile kernel_config kernel_config.debug kernel_config.4.4 patches-4.4
 else
 KERNEL_VERSION=4.9.14
+IMAGE_VERSION=$(KERNEL_VERSION)-0
+IMAGE_MAJOR_VERSION=4.9.x
 DEPS=Dockerfile Makefile kernel_config kernel_config.debug patches-4.9
 endif
+
 kernel.tag: $(DEPS)
 	BUILD=$$( tar cf - $^ | docker build -f $< --build-arg DEBUG=$(DEBUG) --build-arg KERNEL_VERSION=$(KERNEL_VERSION) -q - ) && [ -n "$$BUILD" ] && echo "Built $$BUILD" && echo "$$BUILD" > $@
 
@@ -19,10 +40,9 @@ bzImage: kernel.tag
 	cp x86_64/kernel-modules.tar kernel.tar
 	cp x86_64/bzImage $@
 
-.PHONY: push tag
+.PHONY: image push tag
 
 MEDIA_TOYBOX=mobylinux/toybox-media:0a26fe5f574e444849983f9c4148ef74b3804d55@sha256:5ac38f77b66deb194c9016591b9b096e81fcdc9f7c3e6d01566294a6b4b4ebd2
-SHASUM=alpine:3.5
 
 BASE="$MEDIA_TOYBOX"
 IMAGE=kernel
@@ -32,25 +52,26 @@ default: push
 Dockerfile.media:
 	printf "FROM $(MEDIA_TOYBOX)\nADD . /\n" > $@
 
-hash: Dockerfile.media bzImage kernel.tar $(DEPS)
+image: Dockerfile.media bzImage kernel.tar $(DEPS)
 	tar cf - $^ | docker build --no-cache -t $(IMAGE):build -f Dockerfile.media -
-	tar cf - $^ | DOCKER_CONTENT_TRUST=1 docker run --rm -i $(SHASUM) sha1sum | sed 's/ .*//' > $@
 
-push: hash
-	docker pull mobylinux/$(IMAGE):$(shell cat hash) || \
-		(docker tag $(IMAGE):build mobylinux/$(IMAGE):$(shell cat hash) && \
-		 docker push mobylinux/$(IMAGE):$(shell cat hash))
+push: image
+	docker pull mobylinux/$(IMAGE):$(IMAGE_VERSION) || \
+		(docker tag $(IMAGE):build mobylinux/$(IMAGE):$(IMAGE_VERSION) && \
+		 docker push mobylinux/$(IMAGE):$(IMAGE_VERSION) && \
+		 docker tag $(IMAGE):build mobylinux/$(IMAGE):$(IMAGE_MAJOR_VERSION) && \
+		 docker push mobylinux/$(IMAGE):$(IMAGE_MAJOR_VERSION))
 	docker rmi $(IMAGE):build
 	rm -f hash
 
-tag: hash
-	docker pull mobylinux/$(IMAGE):$(shell cat hash) || \
-		docker tag $(IMAGE):build mobylinux/$(IMAGE):$(shell cat hash)
+tag: image
+	(docker tag $(IMAGE):build mobylinux/$(IMAGE):$(IMAGE_VERSION) && \
+	docker tag $(IMAGE):build mobylinux/$(IMAGE):$(IMAGE_MAJOR_VERSION))
 	docker rmi $(IMAGE):build
 	rm -f hash
 
 .PHONY: clean
 clean:
-	rm -rf x86_64 lib usr sbin kernel.tag hash Dockerfile.media bzImage kernel.tar
+	rm -rf x86_64 lib usr sbin kernel.tag Dockerfile.media bzImage kernel.tar
 
 .DELETE_ON_ERROR: