Merge pull request #1673 from mmamczur/policy_conditions_gep713

Define recommended conditions for policies

Author: k8s-ci-robot

site-src/geps/gep-713.md

@@ -331,6 +331,53 @@ Although these concerns are not unsolvable, they lead to the conclusion that
 a Kubectl plugin should be our primary approach to providing visibility here,
 with a possibility of adding policies to status at a later point.
 
+### Conditions
+Controllers using the Gateway API policy attachment model SHOULD populate the 
+following condition and reasons on policy resources to provide a consistent
+experience across implementations.
+
+```go
+// PolicyConditionType is a type of condition for a policy.
+type PolicyConditionType string
+
+// PolicyConditionReason is a reason for a policy condition.
+type PolicyConditionReason string
+
+const (
+  // PolicyConditionAccepted indicates whether the policy has been accepted or rejected
+  // by a targeted resource, and why.
+  //
+  // Possible reasons for this condition to be True are:
+  //
+  // * "Accepted"
+  //
+  // Possible reasons for this condition to be False are:
+  //
+  // * "Conflicted"
+  // * "Invalid"
+  // * "TargetNotFound"
+  //
+  PolicyConditionAccepted PolicyConditionType = "Accepted"
+
+  // PolicyReasonAccepted is used with the "Accepted" condition when the policy has been
+  // accepted by the targeted resource.
+  PolicyReasonAccepted PolicyConditionReason = "Accepted"
+
+  // PolicyReasonConflicted is used with the "Accepted" condition when the policy has not
+  // been accepted by a targeted resource because there is another policy that targets the same
+  // resource and a merge is not possible.
+  PolicyReasonConflicted PolicyConditionReason = "Conflicted"
+
+  // PolicyReasonInvalid is used with the "Accepted" condition when the policy is syntactically
+  // or semantically invalid.
+  PolicyReasonInvalid PolicyConditionReason = "Invalid"
+
+  // PolicyReasonTargetNotFound is used with the "Accepted" condition when the policy is attached to
+  // an invalid target resource
+  PolicyReasonTargetNotFound PolicyConditionReason = "TargetNotFound"
+)
+```
+
 ### Interaction with Custom Filters and other extension points
 There are multiple methods of custom extension in the Gateway API. Policy
 attachment and custom Route filters are two of these. Policy attachment is