fix missing stored lag reference in OSS consumers (#329)

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Karafka Web changelog
 
+## 0.9.1 (2024-05-03)
+- [Fix] OSS `lag_stored` for not-subscribed consumers causes Web UI to crash.
+
 ## 0.9.0 (2024-04-26)
 - **[Breaking]** Drop Ruby `2.7` support.
 - **[Feature]** Provide ability to stop and quiet running consumers (Pro).

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    karafka-web (0.9.0)
+    karafka-web (0.9.1)
       erubi (~> 1.4)
       karafka (>= 2.4.0, < 2.5.0)
       karafka-core (>= 2.4.0, < 2.5.0)

lib/karafka/web/ui/views/consumers/_consumer.erb

@@ -35,6 +35,6 @@
   </td>
 
   <td>
-    <%= process.lag_stored %>
+    <%= process.lag_hybrid %>
   </td>
 </tr>

lib/karafka/web/version.rb

@@ -3,6 +3,6 @@
 module Karafka
   module Web
     # Current gem version
-    VERSION = '0.9.0'
+    VERSION = '0.9.1'
   end
 end

spec/lib/karafka/web/ui/controllers/consumers_controller_spec.rb

@@ -52,6 +52,35 @@
     end
   end
 
+  context 'when there is an active consumer but without any partitions assigned yet' do
+    before do
+      topics_config.consumers.states = states_topic
+      topics_config.consumers.reports = reports_topic
+
+      report = Fixtures.consumers_reports_json
+      scope = report[:consumer_groups][:example_app6_app][:subscription_groups][:c4ca4238a0b9_0]
+      scope[:topics].clear
+
+      produce(states_topic, Fixtures.consumers_states_file)
+      produce(reports_topic, report.to_json)
+
+      get 'consumers'
+    end
+
+    it do
+      expect(response).to be_ok
+      expect(body).not_to include('partitions: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9')
+      expect(body).to include(support_message)
+      expect(body).not_to include(breadcrumbs)
+      expect(body).not_to include(no_processes)
+      expect(body).not_to include(pagination)
+      expect(body).to include('246 MB')
+      expect(body).to include('shinra:1:1')
+      expect(body).to include('/consumers/shinra:1:1/subscriptions')
+      expect(body).to include('2690818651.82293')
+    end
+  end
+
   context 'when there are active consumers with many partitions assigned' do
     before do
       topics_config.consumers.states = states_topic