registry: Add a simple in-memory cache for indexes

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

diff --git a/src/web/registry.py b/src/web/registry.py
index a87b873c66007e173f3a088f82997a54d424ea0f..b26bd93a0321f9f45638f876017081ac457a44eb 100644 (file)
--- a/src/web/registry.py
+++ b/src/web/registry.py
@@ -21,7 +21,7 @@
 # This file implements the OCI Registry API
 #   https://github.com/opencontainers/distribution-spec/blob/main/spec.md#api
 
-import itertools
+import hashlib
 import json
 import tornado.web
 
@@ -58,6 +58,15 @@ class BaseHandler(base.BaseHandler):
        """
                A base handler for any registry stuff
        """
+       def hash(self, data):
+               if isinstance(data, str):
+                       data = data.encode()
+
+               h = hashlib.new("sha256")
+               h.update(data)
+
+               return "sha256:%s" % h.hexdigest()
+
        async def get_blob(self, distro, digest):
                """
                        Returns a blob if we have it.
@@ -143,6 +152,11 @@ class IndexHandler(BaseHandler):
                pass
 
 
+# Docker is pulling the same content more than once (god knows why). After the
+# ManifestLabelHandler has responded, the client will ask for the same file again
+# by its digest. Therefore we simply cache them and will send them again upon request.
+CACHE = {}
+
 class ManifestLabelHandler(BaseHandler):
        async def head(self, *args, **kwargs):
                return await self.get(*args, **kwargs, send_body=False)
@@ -188,6 +202,9 @@ class ManifestLabelHandler(BaseHandler):
                self.set_header("Content-Type", "application/vnd.oci.image.index.v1+json")
                self.set_header("Content-Length", len(index))
 
+               # Hash and cache
+               CACHE[self.hash(index)] = index
+
                # Send the response
                if send_body:
                        self.finish(index)
@@ -198,6 +215,10 @@ class ManifestHandler(BaseHandler):
                return await self.get(*args, **kwargs, send_body=False)
 
        async def get(self, distro_slug, digest, send_body=True):
+               # If we have this item in the cache, we serve it straight away
+               if digest in CACHE:
+                       return self._get_cached_manifest(digest, send_body=send_body)
+
                # Fetch the distribution
                distro = await self.backend.distros.get_by_slug(distro_slug)
                if not distro:
@@ -215,6 +236,19 @@ class ManifestHandler(BaseHandler):
                if send_body:
                        await self.stream_blob(blob)
 
+       def _get_cached_manifest(self, digest, send_body=True):
+               try:
+                       manifest = CACHE[digest]
+               except KeyError:
+                       raise ManifestUnknownError
+
+               # Set Content-Type
+               self.set_header("Content-Type", "application/vnd.oci.image.index.v1+json")
+               self.set_header("Content-Length", len(index))
+
+               if send_body:
+                       self.finish(manifest)
+
 
 class BlobHandler(BaseHandler):
        async def head(self, *args, **kwargs):