Use Ability to check pre-requisite. Change back to 403 because:

If we're using `can?` it would look weird to use 409

1 files changed, 13 insertions, 0 deletions

diff --git a/app/models/ability.rb b/app/models/ability.rb
index f5950879ccb..0add2f5a34a 100644
--- a/app/models/ability.rb
+++ b/app/models/ability.rb
@@ -19,6 +19,7 @@ class Ability
       when ProjectMember then project_member_abilities(user, subject)
       when User then user_abilities
       when ExternalIssue, Deployment, Environment then project_abilities(user, subject.project)
+      when Ci::Runner then runner_abilities(user, subject)
       else []
       end.concat(global_abilities(user))
     end
@@ -512,6 +513,18 @@ class Ability
       rules
     end
 
+    def runner_abilities(user, runner)
+      if user.is_admin?
+        [:assign_runner]
+      elsif runner.is_shared? || runner.locked?
+        []
+      elsif user.ci_authorized_runners.include?(runner)
+        [:assign_runner]
+      else
+        []
+      end
+    end
+
     def user_abilities
       [:read_user]
     end