Fix Elasticsearch BadRequest exception

ee/lib/elastic/latest/routing.rb

@@ -5,6 +5,8 @@ module Elastic
     module Routing
       extend ActiveSupport::Concern
 
+      ES_ROUTING_MAX_COUNT = 128
+
       def routing_options(options)
         return {} if Feature.disabled?(:elasticsearch_use_routing)
         return {} if options[:public_and_internal_projects]
@@ -31,6 +33,8 @@ module Elastic
       private
 
       def build_routing(ids)
+        return [] if ids.count > ES_ROUTING_MAX_COUNT
+
         ids.map { |id| "project_#{id}" }.join(',')
       end
     end

ee/spec/lib/elastic/latest/routing_spec.rb

@@ -63,6 +63,12 @@ describe Elastic::Latest::Routing do
 
         expect(subject.routing_options(options)).to eq({ routing: project_routing })
       end
+
+      it 'returns empty hash when there are too many project_ids' do
+        max_count = included_class::ES_ROUTING_MAX_COUNT
+
+        expect(subject.routing_options({ project_ids: 1.upto(max_count + 1).to_a })).to eq({})
+      end
     end
 
     context 'when feature flag is disabled' do