Rescue elasticsearch server error in pod logs

changelogs/unreleased/ak-rescue-error.yml

+---
+title: Rescue elasticsearch server error in pod logs
+merge_request: 25367
+author:
+type: fixed

ee/app/services/pod_logs/elasticsearch_service.rb

@@ -51,6 +51,14 @@ module PodLogs
       )
 
       success(result)
+    rescue Elasticsearch::Transport::Transport::ServerError => e
+      ::Gitlab::ErrorTracking.track_exception(e)
+
+      error(_('Elasticsearch returned status code: %{status_code}') % {
+        # ServerError is the parent class of exceptions named after HTTP status codes, eg: "Elasticsearch::Transport::Transport::Errors::NotFound"
+        # there is no method on the exception other than the class name to determine the type of error encountered.
+        status_code: e.class.name.split('::').last
+      })
     end
 
     def etag_path

ee/spec/services/pod_logs/elasticsearch_service_spec.rb

@@ -157,5 +157,19 @@ describe ::PodLogs::ElasticsearchService do
       expect(result[:status]).to eq(:error)
       expect(result[:message]).to eq('Unable to connect to Elasticsearch')
     end
+
+    it 'handles server errors from elasticsearch' do
+      allow_any_instance_of(::Clusters::Applications::ElasticStack)
+        .to receive(:elasticsearch_client)
+        .and_return(Elasticsearch::Transport::Client.new)
+      allow_any_instance_of(::Gitlab::Elasticsearch::Logs)
+        .to receive(:pod_logs)
+        .and_raise(Elasticsearch::Transport::Transport::Errors::ServiceUnavailable.new)
+
+      result = subject.send(:pod_logs, result_arg)
+
+      expect(result[:status]).to eq(:error)
+      expect(result[:message]).to eq('Elasticsearch returned status code: ServiceUnavailable')
+    end
   end
 end

locale/gitlab.pot

@@ -7017,6 +7017,9 @@ msgstr ""
 msgid "Elasticsearch integration. Elasticsearch AWS IAM."
 msgstr ""
 
+msgid "Elasticsearch returned status code: %{status_code}"
+msgstr ""
+
 msgid "Elastic|None. Select namespaces to index."
 msgstr ""