Remove outdated DOCKER_BUILDKIT workarounds (#133)

BuildKit is the default since Docker 23. The explicit `export
DOCKER_BUILDKIT=1` and related comments are no longer needed and can
interfere with attestation on push.

Signed-off-by: Adrian Cole <adrian@tetrate.io>

Author: codefromthecrypt

build-bin/docker/docker_build

@@ -10,10 +10,5 @@ docker_tag=${1?full docker_tag is required. Ex openzipkin/zipkin:test}
 version=${2:-}
 docker_args=$($(dirname "$0")/docker_args ${version})
 
-# We don't need build kit, but Docker 20.10 no longer accepts --platform
-# without it. It is simpler to always enable it vs require maintainers to use
-# alternate OCI tools. See https://github.com/moby/moby/issues/41552
-export DOCKER_BUILDKIT=1
-
 echo "Building image ${docker_tag}"
 docker build --network=host --pull ${docker_args} --tag ${docker_tag} .

build-bin/docker/docker_push

@@ -10,20 +10,11 @@
 #
 # Note: In CI, `configure_docker_push` must be called before invoking this.
 #
-# Avoid buildx on push for reasons including:
-#  * Caching is more complex as builder instances must be considered
-#  * Platform builds run in parallel, leading to port conflict failures (ex in cassandra)
-#  * 0.4.2 multi-platform builds have failed due to picking the wrong image for a FROM instruction
 set -ue
 
 docker_image=${1?docker_image is required, notably without a tag. Ex openzipkin/zipkin}
 version=${2:-master}
 
-# We don't need build kit, but Docker 20.10 no longer accepts --platform
-# without it. It is simpler to always enable it vs require maintainers to use
-# alternate OCI tools. See https://github.com/moby/moby/issues/41552
-export DOCKER_BUILDKIT=1
-
 case ${version} in
   master )
     is_release=false
@@ -99,14 +90,7 @@ else
       manifest_tags="${manifest_tags} ${manifest_tag}"
     done
 
-    docker manifest create ${tag} ${manifest_tags}
-
-    for manifest_tag in ${manifest_tags}; do
-      docker_arch=$(echo ${manifest_tag} | sed 's/.*-//g')
-      docker manifest annotate ${tag} ${manifest_tag} --os linux --arch ${docker_arch}
-    done
-
-    echo "Pushing manifest ${manifest_tag}..."
-    docker manifest push -p ${tag}
+    echo "Pushing manifest ${tag}..."
+    docker buildx imagetools create --tag ${tag} ${manifest_tags}
   done
 fi