Add COPR document to dist-git ARC investigation

Signed-off-by: Michal Konecny <mkonecny@redhat.com>

docs/dist-git-move/copr.rst

@@ -0,0 +1,64 @@
+.. _copr:
+
+Pagure Dist Git Interactions With COPR
+====
+
+`Copr <https://copr.fedorainfracloud.org/>`_ ("Community projects") is a service
+that builds your open-source projects and creates your own RPM repositories.
+
+Possible Interactions
+----
+
+The following are a set of documented interactions possible between Pagure Dist
+Git and COPR.
+
+Builds logic
+^^^^
+
+- COPR is using API calls for flagging dist-git commits or pull requests in
+  `build_logic.py module <https://github.com/fedora-copr/copr/blob/2789f06b36be5c13eae83c8695eb36de03a7728f/frontend/coprs_frontend/coprs/logic/builds_logic.py#L1101-L1109>`_.
+  It is calling `/api/0/<package_name>/pull-request/<pr_id>/flag` and
+  `/api/0/<package_name>/c/<commit_id>/flag` API endpoints.
+
+CLI client
+^^^^
+
+- COPR is doing `git clone` from dist-git, which is wrapped in
+  `copr-distgit-client clone --dist-git fedora <pkgname>`.
+
+Fedora messaging
+^^^^
+
+- COPR is listening to following dist-git topics:
+  * `org.fedoraproject.prod.pagure.git.receive`
+  * `org.fedoraproject.prod.pagure.pull-request.new`
+  * `org.fedoraproject.prod.pagure.pull-request.rebased`
+  * `org.fedoraproject.prod.pagure.pull-request.updated`
+  * `org.fedoraproject.prod.pagure.pull-request.comment.added`
+- These topics are configured in
+  `frontend messaging configuration <https://pagure.io/fedora-infra/ansible/blob/main/f/roles/copr/frontend/templates/fedora-messaging/copr_messaging.toml>`_.
+
+Changes proposed
+----
+
+In order to switch out Pagure Dist Git for an alternative that provides a
+relatively compatible API pattern, the following changes must be made in the
+places mentioned below.
+
+Necessary
+^^^^
+
+- There are few configuration files that points to current dist-git. If the
+  URL should change we would need to update
+  `rpkg.conf <https://pagure.io/fedora-infra/ansible/blob/main/f/roles/copr/backend/templates/provision/rpkg.conf.j2>`_
+  and
+  `main.ini <https://pagure.io/fedora-infra/ansible/blob/main/f/roles/copr/backend/templates/provision/copr-rpmbuild/main.ini.j2>`_
+  with the URL to new service.
+- In case the message schema of the new dist-git will change we need to update consumed topics in
+  `frontend messaging configuration <https://pagure.io/fedora-infra/ansible/blob/main/f/roles/copr/frontend/templates/fedora-messaging/copr_messaging.toml>`_.
+
+Unnecessary
+^^^^
+
+- There isn't much interactions between Fedora dist-git and COPR and no change
+  is needed that would be unnecessary to do in case dist-git will change.

docs/dist-git-move/index.rst

@@ -43,6 +43,7 @@ Index
 .. toctree::
     :maxdepth: 1
 
+    copr
     hotness
     notifications
     toddlers