build: Rework image tagging

We should really create proper multi-arch images, ... but we can at
least improve the current system we have of tagging the image with the
host arch.

The problem with the way we do it now is that the two tags (the plain
one and the one with the arch) cause docker rmi to refuse to delete the
image until one if explicitly untagged.

Instead we can only create the tag with the arch name in it temporarily,
when we're pulling/pushing.

To make that work with the allcross image we need to drop --pull, so
that the FROM will use the local image without the arch name.

Author: mpe

build/scripts/image.sh

@@ -34,23 +34,61 @@ elif [[ "$task" == "pull-image" ]]; then
 	exit $?
     fi
 
+    # Tag the arch specific image with the generic tag
     cmd="$DOCKER tag $arch_image $image"
     (set -x; $cmd)
+    if [[ $? -ne 0 ]]; then
+        echo "Error: tagging $arch_image as $image?" >&2
+        exit 1
+    fi
+
+    # Remove the arch tag (not the whole image)
+    cmd="$DOCKER rmi $arch_image"
+    (set -x; $cmd)
+    if [[ $? -ne 0 ]]; then
+        echo "Error: untagging $arch_image?" >&2
+        exit 1
+    fi
 
-    exit $?
+    exit 0
 elif [[ "$task" == "push-image" ]]; then
     if [[ -n "$DOCKER_PASSWORD" && -n "$DOCKER_USER" ]]; then
 	cmd="$DOCKER login -u $DOCKER_USER -p $DOCKER_PASSWORD"
 	(set -x; $cmd)
     fi
 
-    image="$image-$(uname -m)"
-    cmd="$DOCKER push $image"
+    # Temporarily tag the image with the arch
+    arch_image="$image-$(uname -m)"
+    cmd="$DOCKER tag $image $arch_image"
+    (set -x; $cmd)
+    if [[ $? -ne 0 ]]; then
+        echo "Error: tagging $image as $arch_image?" >&2
+        exit 1
+    fi
+
+    cmd="$DOCKER push $arch_image"
+    (set -x; $cmd)
+    if [[ $? -ne 0 ]]; then
+        echo "Error: pushing $arch_image?" >&2
+        exit 1
+    fi
+
+    # Remove the arch tag (not the whole image)
+    cmd="$DOCKER rmi $arch_image"
     (set -x; $cmd)
-    exit $?
+    if [[ $? -ne 0 ]]; then
+        echo "Error: untagging $arch_image?" >&2
+        exit 1
+    fi
+
+    exit 0
 fi
 
-cmd="$DOCKER build --pull -f $distro/Dockerfile "
+cmd="$DOCKER build -f $distro/Dockerfile "
+
+if [[ "$distro" != "ubuntu-allcross" ]]; then
+    cmd+="--pull "
+fi
 
 if [[ -n "$http_proxy" ]]; then
     cmd+="--build-arg http_proxy=$http_proxy "
@@ -73,7 +111,7 @@ from="${DOCKER_REGISTRY}$distro:$version"
 if [[ "$distro" == "docs" ]]; then
     from="${DOCKER_REGISTRY}ubuntu:$version"
 elif [[ "$distro" == "ubuntu-allcross" ]]; then
-	from="${DOCKER_REGISTRY}linuxppc/build:ubuntu-$version-$(uname -m)"
+	from="${DOCKER_REGISTRY}linuxppc/build:ubuntu-$version"
 elif [[ "$distro" == "korg" ]]; then
     cmd+="--build-arg compiler_version=$version "
 
@@ -94,7 +132,6 @@ cmd+="--build-arg uid=$UID "
 cmd+="--build-arg gid=$GID "
 cmd+="--build-arg from=$from "
 cmd+="--build-arg apt_mirror=$APT_MIRROR "
-cmd+="-t $image-$(uname -m) "
 cmd+="-t $image ."
 
 (set -x; $cmd)