greenwave policy: fix applying per repo gating rules

The policies Kevin took out in f9e7d727 were misleadingly named.
They didn't have anything to do with taskotron any more. The
actual difference between them and the "no_requirements" policies
is that they each have a RemoteRule rule, which is the special
sauce that makes gating policies in package repos work. Without
that, those policies are ignored.

This commit restores those policies, changes all the policy names
to more accurate and information ones, and adds quite a lot of
explanatory comments.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

roles/openshift-apps/greenwave/templates/fedora.yaml

@@ -50,7 +50,57 @@ rules:
   - !PassingTestCaseRule {test_case_name: compose.server_role_deploy_domain_controller, scenario: "fedora.Server-dvd-iso.x86_64.64bit"}
 
 --- !Policy
-id: "no_requirements_testing"
+# _kojibuild_ policies are for koji_build subjects; Fedora CI tests run at
+# at the Koji build level and report results which will be found by these
+# policies. We must have at least one kojibuild policy for each Fedora
+# version Bodhi might operate on (because ignore_missing_policy is false
+# for the koji_build subject type, as config stands at 2020-11, so Bodhi
+# will fail if it queries Greenwave and no koji_build policy matches the
+# query terms).
+
+# _update_ policies are for bodhi_update subjects; Fedora openQA tests run
+# at the Bodhi update level and report results which will be found by these
+# policies. ignore_missing_policy is true for the bodhi_update subject type
+# (in upstream Greenwave default config, as of 2020-11) so it is OK for
+# there not to be any matching policy of this type that matches when Bodhi
+# queries.
+
+# note that policies are *additive*. If a query matches multiple of these
+# policies, all the rules in all the matched policies are applied.
+
+id: "fedora_mainline_kojibuild_remoterule"
+product_versions:
+  - fedora-rawhide
+  - fedora-34
+  - fedora-33
+  - fedora-32
+decision_context: bodhi_update_push_testing
+subject_type: koji_build
+rules:
+  # this means "apply gating configs in package repos"
+  # see Greenwave docs/policies.rst for more details
+  - !RemoteRule {}
+
+--- !Policy
+id: "fedora_mainline_kojibuild_remoterule"
+product_versions:
+  - fedora-rawhide
+  - fedora-34
+  - fedora-33
+  - fedora-32
+decision_context: bodhi_update_push_stable
+subject_type: koji_build
+rules:
+  # this means "apply gating configs in package repos"
+  # see Greenwave docs/policies.rst for more details
+  - !RemoteRule {}
+
+--- !Policy
+id: "kojibuild_no_requirements_testing"
+  # this is a null policy, it enforces no requirements. It is needed
+  # because at least one policy must match for koji_build subjects.
+  # if a query matches this policy and no other, no requirements will
+  # be applied
 product_versions:
   - fedora-34-modular
   - fedora-34-containers
@@ -61,9 +111,6 @@ product_versions:
   - fedora-32-modular
   - fedora-32-containers
   - fedora-32-flatpaks
-  - fedora-34
-  - fedora-33
-  - fedora-32
   - fedora-epel-8
   - fedora-epel-8-modular
   - fedora-epel-7
@@ -73,7 +120,11 @@ subject_type: koji_build
 rules: []
 
 --- !Policy
-id: "no_requirements_for_stable"
+id: "kojibuild_no_requirements_stable"
+  # this is a null policy, it enforces no requirements. It is needed
+  # because at least one policy must match for koji_build subjects.
+  # if a query matches this policy and no other, no requirements will
+  # be applied
 product_versions:
   - fedora-34-modular
   - fedora-34-containers
@@ -84,9 +135,6 @@ product_versions:
   - fedora-32-modular
   - fedora-32-containers
   - fedora-32-flatpaks
-  - fedora-34
-  - fedora-33
-  - fedora-32
   - fedora-epel-8
   - fedora-epel-8-modular
   - fedora-epel-7
@@ -97,8 +145,7 @@ subject_type: koji_build
 rules: []
 
 --- !Policy
-# openQA policies
-id: "openqa_release_critical_tasks_for_testing"
+id: "fedora_mainline_update_rules_for_testing"
 product_versions:
   - fedora-rawhide
   - fedora-34
@@ -107,10 +154,12 @@ product_versions:
 decision_context: bodhi_update_push_testing
 subject_type: bodhi_update
 rules:
+  # this means "apply gating configs in package repos"
+  # see Greenwave docs/policies.rst for more details
   - !RemoteRule {}
 
 --- !Policy
-id: "openqa_release_critical_tasks_for_stable"
+id: "fedora_mainline_update_rules_for_stable"
 product_versions:
   - fedora-rawhide
   - fedora-34
@@ -119,4 +168,6 @@ product_versions:
 decision_context: bodhi_update_push_stable
 subject_type: bodhi_update
 rules:
+  # this means "apply gating configs in package repos"
+  # see Greenwave docs/policies.rst for more details
   - !RemoteRule {}