releng: fix upload of multiarch images to forgejo

Forgejo appears to immediately delete registry content that is
overwritten. This means that we are forced to delete our previous
workaround of making a temporary tag and use a new, more absurd
workaround of making an entire temporary image that we basically only
need to create to get its hash.

However, on the plus side, the new workaround doesn't create garbage
tags to begin with, which means that we don't have to deal with GitHub
not implementing the standardized tag delete endpoint and instead
only implementing a proprietary one.

Upstream-Bug: https://github.com/containers/skopeo/issues/2354
Change-Id: I220e7ce9a17fd230c38882f12c009a166dcc9336

1 files changed, 19 insertions, 10 deletions

diff --git a/releng/docker.xsh b/releng/docker.xsh
index 20fb30cd3..13bdd7868 100644
--- a/releng/docker.xsh
+++ b/releng/docker.xsh
@@ -19,6 +19,7 @@ def check_all_logins(env: RelengEnvironment):
         check_login(target)
 
 def check_login(target: DockerTarget):
+    log.info('Checking login for %s', target.registry_name)
     skopeo login @(target.registry_name())
 
 def upload_docker_images(target: DockerTarget, paths: list[Path]):
@@ -43,7 +44,23 @@ def upload_docker_images(target: DockerTarget, paths: list[Path]):
 
         for path in paths:
             digest_file = tmp / (path.name + '.digest')
-            inspection = json.loads($(skopeo inspect docker-archive:@(path)))
+            tmp_image = tmp / 'tmp-image.tar.gz'
+
+            # insecure-policy: we don't have any signature policy, we are just uploading an image
+            #
+            # Absurd: we copy it into an OCI image first so we can get the hash
+            # we need to upload it untagged, because skopeo has no "don't tag
+            # this" option.
+            # The reason for this is that forgejo's container registry throws
+            # away old versions of tags immediately, so we cannot use a temp
+            # tag, and it *does* reduce confusion to not upload tags that
+            # should not be used.
+            #
+            # Workaround for: https://github.com/containers/skopeo/issues/2354
+            log.info('skopeo copy to temp oci-archive %s', tmp_image)
+            skopeo --insecure-policy copy --format oci --all --digestfile @(digest_file) docker-archive:@(path) oci-archive:@(tmp_image)
+
+            inspection = json.loads($(skopeo inspect oci-archive:@(tmp_image)))
 
             docker_arch = inspection['Architecture']
             docker_os = inspection['Os']
@@ -51,21 +68,13 @@ def upload_docker_images(target: DockerTarget, paths: list[Path]):
 
             log.info('Pushing image %s for %s to %s', path, docker_arch, target.registry_path)
 
-            # insecure-policy: we don't have any signature policy, we are just uploading an image
-            # We upload to a junk tag, because otherwise it will upload to `latest`, which is undesirable
-            skopeo --insecure-policy copy --format oci --digestfile @(digest_file) docker-archive:@(path) docker://@(target.registry_path):temp
-
             digest = digest_file.read_text().strip()
+            skopeo --insecure-policy copy --preserve-digests --all oci-archive:@(tmp_image) f'docker://{target.registry_path}@{digest}'
 
             # skopeo doesn't give us the manifest size directly, so we just ask the registry
             metadata = reg.image_info(target.registry_path, digest)
 
             manifests.append(OCIIndexItem(metadata=metadata, architecture=docker_arch, os=docker_os))
-    # delete the temp tag, which we only have to create because of skopeo
-    # limitations anyhow (it seems to not have a way to say "don't tag it, find
-    # your checksum and put it there")
-    # FIXME: this is not possible because GitHub only has a proprietary API for it. amazing. 11/10.
-    # reg.delete_tag(target.registry_path, 'temp')
 
     log.info('Pushed images to %r, building a bigger and more menacing manifest from %r with metadata %r', target, manifests, meta)
     # send the multiarch manifest to each tag