Adjust "hack/make/.detect-daemon-osarch" to be the source of truth for "platform detection"

Instead of being split between three files, let's let `hack/make/.detect-daemon-osarch` be our single source of truth for multiarch detection/vars.  Not only does it make it slightly easier to make sure we change everything properly when these bits have to change, but it also makes it so that all bits of `hack/make.sh` (especially `hack/make/.ensure-frozen-images`) work properly outside the context of the `Makefile` on all platforms.

Signed-off-by: Andrew "Tianon" Page <admwiggin@gmail.com>

Makefile

@@ -1,30 +1,8 @@
 .PHONY: all binary build cross default docs docs-build docs-shell shell test test-docker-py test-integration-cli test-unit validate
 
 # get OS/Arch of docker engine
-DOCKER_OSARCH := $(shell bash -c 'source hack/make/.detect-daemon-osarch && echo $${DOCKER_ENGINE_OSARCH:+$$DOCKER_CLIENT_OSARCH}')
-# default for linux/amd64 and others
-DOCKERFILE := Dockerfile
-# switch to different Dockerfile for linux/arm
-ifeq ($(DOCKER_OSARCH), linux/arm)
-	DOCKERFILE := Dockerfile.armhf
-else
-ifeq ($(DOCKER_OSARCH), linux/arm64)
-	DOCKERFILE := Dockerfile.aarch64
-else
-ifeq ($(DOCKER_OSARCH), linux/ppc64le)
-	DOCKERFILE := Dockerfile.ppc64le
-else
-ifeq ($(DOCKER_OSARCH), linux/s390x)
-	DOCKERFILE := Dockerfile.s390x
-else
-ifeq ($(DOCKER_OSARCH), windows/amd64)
-	DOCKERFILE := Dockerfile.windows
-endif
-endif
-endif
-endif
-endif
-export DOCKERFILE
+DOCKER_OSARCH := $(shell bash -c 'source hack/make/.detect-daemon-osarch && echo $${DOCKER_ENGINE_OSARCH:-$$DOCKER_CLIENT_OSARCH}')
+DOCKERFILE := $(shell bash -c 'source hack/make/.detect-daemon-osarch && echo $${DOCKERFILE}')
 
 # env vars passed through directly to Docker's build scripts
 # to allow things like `make DOCKER_CLIENTONLY=1 binary` easily
@@ -37,7 +15,6 @@ DOCKER_ENVS := \
 	-e DOCKER_CLIENTONLY \
 	-e DOCKER_DEBUG \
 	-e DOCKER_EXPERIMENTAL \
-	-e DOCKERFILE \
 	-e DOCKER_GRAPHDRIVER \
 	-e DOCKER_INCREMENTAL_BINARY \
 	-e DOCKER_REMAP_ROOT \

hack/make/.detect-daemon-osarch

@@ -1,34 +1,63 @@
 #!/bin/bash
 set -e
 
+docker-version-osarch() {
+	local target="$1" # "Client" or "Server"
+	local fmtStr="{{.${target}.Os}}/{{.${target}.Arch}}"
+	if docker version -f "$fmtStr" 2>/dev/null; then
+		# if "docker version -f" works, let's just use that!
+		return
+	fi
+	docker version | awk '
+		$1 ~ /^(Client|Server):$/ { section = 0 }
+		$1 == "'"$target"':" { section = 1; next }
+		section && $1 == "OS/Arch:" { print $2 }
+	'
+}
+
 # Retrieve OS/ARCH of docker daemon, eg. linux/amd64
-export DOCKER_ENGINE_OSARCH="$(docker version | awk '
-	$1 == "Client:" { server = 0; next }
-	$1 == "Server:" { server = 1; next }
-	server && $1 == "OS/Arch:" { print $2 }
-')"
+export DOCKER_ENGINE_OSARCH="$(docker-version-osarch 'Server')"
 export DOCKER_ENGINE_GOOS="${DOCKER_ENGINE_OSARCH%/*}"
 export DOCKER_ENGINE_GOARCH="${DOCKER_ENGINE_OSARCH##*/}"
 DOCKER_ENGINE_GOARCH=${DOCKER_ENGINE_GOARCH:=amd64}
 
 # and the client, just in case
-export DOCKER_CLIENT_OSARCH="$(docker version | awk '
-	$1 == "Client:" { client = 1; next }
-	$1 == "Server:" { client = 0; next }
-	client && $1 == "OS/Arch:" { print $2 }
-')"
+export DOCKER_CLIENT_OSARCH="$(docker-version-osarch 'Client')"
+export DOCKER_CLIENT_GOOS="${DOCKER_CLIENT_OSARCH%/*}"
+export DOCKER_CLIENT_GOARCH="${DOCKER_CLIENT_OSARCH##*/}"
+DOCKER_CLIENT_GOARCH=${DOCKER_CLIENT_GOARCH:=amd64}
 
 # Retrieve the architecture used in contrib/builder/(deb|rpm)/$PACKAGE_ARCH/
-PACKAGE_ARCH="amd64"
-case "$DOCKER_ENGINE_OSARCH" in
-	linux/arm)
+PACKAGE_ARCH='amd64'
+case "${DOCKER_ENGINE_GOARCH:-$DOCKER_CLIENT_GOARCH}" in
+	arm)
 		PACKAGE_ARCH='armhf'
 		;;
-	linux/ppc64le)
-		PACKAGE_ARCH='ppc64le'
+	arm64)
+		PACKAGE_ARCH='aarch64'
+		;;
+	amd64|ppc64le|s390x)
+		PACKAGE_ARCH="${DOCKER_ENGINE_GOARCH:-$DOCKER_CLIENT_GOARCH}"
 		;;
-	linux/s390x)
-		PACKAGE_ARCH='s390x'
+	*)
+		echo >&2 "warning: not sure how to convert '$DOCKER_ENGINE_GOARCH' to a 'Docker' arch, assuming '$PACKAGE_ARCH'"
 		;;
 esac
 export PACKAGE_ARCH
+
+DOCKERFILE='Dockerfile'
+TEST_IMAGE_NAMESPACE=
+case "$PACKAGE_ARCH" in
+	amd64)
+		case "${DOCKER_ENGINE_GOOS:-$DOCKER_CLIENT_GOOS}" in
+			windows)
+				DOCKERFILE='Dockerfile.windows'
+				;;
+		esac
+		;;
+	*)
+		DOCKERFILE="Dockerfile.$PACKAGE_ARCH"
+		TEST_IMAGE_NAMESPACE="$PACKAGE_ARCH"
+		;;
+esac
+export DOCKERFILE TEST_IMAGE_NAMESPACE

hack/make/.ensure-frozen-images

@@ -9,25 +9,9 @@ images=(
 	hello-world:latest
 )
 
-imagePrefix=
-case "$DOCKER_ENGINE_OSARCH" in
-	linux/arm)
-		imagePrefix='armhf'
-		;;
-	linux/arm64)
-		imagePrefix='aarch64'
-		;;
-	linux/ppc64le)
-		imagePrefix='ppc64le'
-		;;
-	linux/s390x)
-		imagePrefix='s390x'
-		;;
-esac
-
-if [ "$imagePrefix" ]; then
+if [ "$TEST_IMAGE_NAMESPACE" ]; then
 	for (( i = 0; i < ${#images[@]}; i++ )); do
-		images[$i]="$imagePrefix/${images[$i]}"
+		images[$i]="$TEST_IMAGE_NAMESPACE/${images[$i]}"
 	done
 fi
 
@@ -58,7 +42,7 @@ if ! docker inspect "${images[@]}" &> /dev/null; then
 					inCont = 0;
 				}
 			}
-		' "${DOCKERFILE:=Dockerfile}" | sh -x
+		' "$DOCKERFILE" | sh -x
 		# Do not use a subshell for the following command. Windows to Linux CI
 		# runs bash 3.x so will not trap an error in a subshell.
 		# http://stackoverflow.com/questions/22630363/how-does-set-e-work-with-subshells
@@ -66,9 +50,9 @@ if ! docker inspect "${images[@]}" &> /dev/null; then
 	fi
 fi
 
-if [ "$imagePrefix" ]; then
+if [ "$TEST_IMAGE_NAMESPACE" ]; then
 	for image in "${images[@]}"; do
-		target="${image#$imagePrefix/}"
+		target="${image#$TEST_IMAGE_NAMESPACE/}"
 		if [ "$target" != "$image" ]; then
 			# tag images to ensure that all integrations work with the defined image names
 			docker tag "$image" "$target"