Fix edge case where meeting can be recreated on cordoned server

Author: farhatahmad

app/controllers/bigbluebutton_api_controller.rb

@@ -171,6 +171,14 @@ def create
       # Check if meeting is already running
       meeting = Meeting.find(params[:meetingID], @tenant&.id)
       server = meeting.server
+
+      # Handle edge case where stale meeting persists on cordoned server
+      if server.cordoned? && !meeting_running_on_server?(meeting)
+        logger.info("Meeting #{params[:meetingID]} no longer running on cordoned server #{server.id}; re-allocating.")
+        meeting.destroy!
+        raise ApplicationRedisRecord::RecordNotFound.new('stale meeting on cordoned server', 'Meeting', params[:meetingID])
+      end
+
       logger.debug("Found existing meeting #{params[:meetingID]} on BigBlueButton server #{server.id}.")
     rescue ApplicationRedisRecord::RecordNotFound
       begin
@@ -572,6 +580,16 @@ def pass_through_params(excluded_params)
           .to_unsafe_hash
   end
 
+  def meeting_running_on_server?(meeting)
+    server = meeting.server
+    uri = encode_bbb_uri('isMeetingRunning', server.url, server.secret, 'meetingID' => meeting.id)
+    response = get_post_req(uri, **bbb_req_timeout(server))
+    response.at_xpath('/response/running')&.text == 'true'
+  rescue StandardError => e
+    logger.warn("Could not verify meeting #{meeting.id} on cordoned server #{server.id}: #{e}")
+    false
+  end
+
   # Success response if there are no meetings on any servers
   def no_meetings_response
     Nokogiri::XML::Builder.new do |xml|

spec/requests/bigbluebutton_api_controller_spec.rb

@@ -538,6 +538,43 @@
         expect(new_server.load).to eq(1)
       end
 
+      context 'when the meeting is pinned to a cordoned server' do
+        let!(:cordoned_server) do
+          s = create(:server)
+          s.state = 'cordoned'
+          s.save!
+          s
+        end
+
+        it 're-allocates to an available server when the meeting is no longer running there' do
+          Meeting.find_or_create_with_server!('test-meeting-1', cordoned_server, 'mp')
+
+          stub_request(:get, /#{Regexp.escape(cordoned_server.url)}isMeetingRunning/)
+            .to_return(body: '<response><returncode>SUCCESS</returncode><running>false</running></response>')
+          stub_create = stub_request(:get, /#{Regexp.escape(server.url)}create/)
+                        .to_return(body: '<response><returncode>SUCCESS</returncode><meetingID>test-meeting-1</meetingID></response>')
+
+          get bigbluebutton_api_create_url, params: { meetingID: 'test-meeting-1', moderatorPW: 'mp', voiceBridge: '1234567' }
+
+          expect(stub_create).to have_been_requested
+          expect(Meeting.find('test-meeting-1').server.id).to eq(server.id)
+        end
+
+        it 'keeps the meeting on the cordoned server when it is still running there' do
+          Meeting.find_or_create_with_server!('test-meeting-1', cordoned_server, 'mp')
+
+          stub_request(:get, /#{Regexp.escape(cordoned_server.url)}isMeetingRunning/)
+            .to_return(body: '<response><returncode>SUCCESS</returncode><running>true</running></response>')
+          stub_create = stub_request(:get, /#{Regexp.escape(cordoned_server.url)}create/)
+                        .to_return(body: '<response><returncode>SUCCESS</returncode><meetingID>test-meeting-1</meetingID></response>')
+
+          get bigbluebutton_api_create_url, params: { meetingID: 'test-meeting-1', moderatorPW: 'mp', voiceBridge: '1234567' }
+
+          expect(stub_create).to have_been_requested
+          expect(Meeting.find('test-meeting-1').server.id).to eq(cordoned_server.id)
+        end
+      end
+
       it "returns an appropriate error on timeout" do
         params = { meetingID: "test-meeting-1", moderatorPW: "mp", voiceBridge: "1234567" }