Proposal: Move docker-registry to separate repository

Signed-off-by: Gladkov Alexey <[email protected]>

Author: legionus

docs/proposals/docker-registry-split.md

@@ -0,0 +1,141 @@
+# Move docker-registry to separate repository
+
+## Problem
+
+The `docker/distribution` has a lot of dependencies. Since `kubernetes` began to use docker/distribution
+it has become very difficult to update `docker/distribution` in the part where you need to combine the
+dependencies of these projects. There is no guarantee that the merge of the dependencies would not make
+regression in these projects.
+
+## Constraints and Assumptions
+
+The docker-registry is highly integrated in a common code-base so it is very difficult to describe
+all the difficulties of separation.
+
+## Investigation
+
+### etcd
+
+The docker-registry does not have its own `etcd`. All metadata are stored to the `origin` database using
+client API.
+
+### code-base
+
+The `origin` interacts with the docker-registry only through client library (no internal calls),
+but this cannot be said about docker-regisrty.
+
+1. docker-registry should use [clientsets](https://github.com/kubernetes/kubernetes/blob/master/docs/devel/generating-clientset.md)
+of `origin`.
+2. docker-registry should use [clientsets](https://github.com/kubernetes/kubernetes/blob/master/docs/devel/generating-clientset.md)
+of `kubernetes`.
+3. We need to create versioned client (clientsets?) for docker-registry as well.
+4. We need to split some utilities to reduce the number of dependencies to `origin`.
+5. We need to make common framework for tests. Currently docker-registry uses a common test utilities and clients.
+
+### testing
+
+Use versioning clients will allow us maintain compatibility between repositories. In this case,
+in the jenkins job for `origin` we can build the image from the separate repository before build and
+test `origin` itself. Right now we make docker-registry image from the `origin` repository.
+
+### release scripts
+
+/TODO/
+
+## Dependencies
+
+`cmd/dockerregistry` uses
+```
+github.com/openshift/origin/pkg/api/install
+github.com/openshift/origin/pkg/cmd/dockerregistry
+github.com/openshift/origin/pkg/cmd/util                 (Env)
+github.com/openshift/origin/pkg/cmd/util/serviceability  (BehaviorOnPanic, Profile)
+
+k8s.io/kubernetes/pkg/api/install
+k8s.io/kubernetes/pkg/apis/extensions/install
+```
+
+`pkg/cmd/dockerregistry` uses
+```
+github.com/openshift/origin/pkg/cmd/server/crypto
+github.com/openshift/origin/pkg/dockerregistry/server
+```
+
+`pkg/dockerregistry/server` uses
+```
+github.com/openshift/origin/pkg/authorization/api
+github.com/openshift/origin/pkg/client
+github.com/openshift/origin/pkg/cmd/util/clientcmd
+github.com/openshift/origin/pkg/image/admission          (AdmitImage)
+github.com/openshift/origin/pkg/image/api
+github.com/openshift/origin/pkg/image/importer
+github.com/openshift/origin/pkg/quota/util               (IsErrorQuotaExceeded)
+github.com/openshift/origin/pkg/util/httprequest         (SchemeHost)
+
+k8s.io/kubernetes/pkg/api
+k8s.io/kubernetes/pkg/api/errors
+k8s.io/kubernetes/pkg/client/cache
+k8s.io/kubernetes/pkg/client/restclient
+k8s.io/kubernetes/pkg/client/unversioned
+k8s.io/kubernetes/pkg/runtime
+k8s.io/kubernetes/pkg/util
+k8s.io/kubernetes/pkg/util/sets
+```
+
+`pkg/dockerregistry/server` tests uses
+```
+github.com/openshift/origin/pkg/api/install
+github.com/openshift/origin/pkg/api/latest
+github.com/openshift/origin/pkg/authorization/api
+github.com/openshift/origin/pkg/client
+github.com/openshift/origin/pkg/client/testclient
+github.com/openshift/origin/pkg/cmd/util/clientcmd
+github.com/openshift/origin/pkg/dockerregistry/testutil
+github.com/openshift/origin/pkg/image/admission/testutil
+github.com/openshift/origin/pkg/image/api
+github.com/openshift/origin/pkg/user/api
+
+k8s.io/kubernetes/pkg/api
+k8s.io/kubernetes/pkg/apimachinery/registered
+k8s.io/kubernetes/pkg/client/restclient
+k8s.io/kubernetes/pkg/client/unversioned
+k8s.io/kubernetes/pkg/client/unversioned/testclient
+k8s.io/kubernetes/pkg/runtime
+k8s.io/kubernetes/pkg/util
+k8s.io/kubernetes/pkg/util/diff
+```
+
+### docker-registry -> k8s -> docker/distribution
+
+Right now we have dependencies between kubernetes and docker/distribution:
+```
+cmd/dockerregistry/main.go:
+`-> github.com/openshift/origin/pkg/api/install, k8s.io/kubernetes/pkg/api/install
+ `-> k8s.io/kubernetes/pkg/api/v1
+  `-> k8s.io/kubernetes/pkg/util/parsers
+   `-> github.com/docker/distribution/reference
+
+pkg/dockerregistry/server/repositorymiddleware.go:
+`-> k8s.io/kubernetes/pkg/client/restclient
+ `-> k8s.io/kubernetes/pkg/api/v1
+  `-> k8s.io/kubernetes/pkg/util/parsers
+   `-> github.com/docker/distribution/reference
+
+pkg/dockerregistry/server/token.go:
+`-> k8s.io/kubernetes/pkg/client/restclient
+ `-> k8s.io/kubernetes/pkg/api/v1
+  `-> k8s.io/kubernetes/pkg/util/parsers
+   `-> github.com/docker/distribution/reference
+
+pkg/dockerregistry/server/auth.go:
+`-> k8s.io/kubernetes/pkg/client/restclient
+ `-> k8s.io/kubernetes/pkg/api/v1
+  `-> k8s.io/kubernetes/pkg/util/parsers
+   `-> github.com/docker/distribution/reference
+
+pkg/dockerregistry/testutil/util.go:
+`-> k8s.io/kubernetes/pkg/client/unversioned/testclient
+ `-> k8s.io/kubernetes/pkg/api/v1
+  `-> k8s.io/kubernetes/pkg/util/parsers
+   `-> github.com/docker/distribution/reference
+```