Add event store for Geo::CacheInvalidationEvent

ee/app/services/geo/cache_invalidation_event_store.rb

+# frozen_string_literal: true
+
+module Geo
+  class CacheInvalidationEventStore < EventStore
+    self.event_type = :cache_invalidation_event
+
+    attr_reader :key
+
+    def initialize(key)
+      @key = key
+    end
+
+    private
+
+    def build_event
+      Geo::CacheInvalidationEvent.new(key: key)
+    end
+
+    # This is called by ProjectLogHelpers to build json log with context info
+    #
+    # @see ::Gitlab::Geo::ProjectLogHelpers
+    def base_log_data(message)
+      {
+        class: self.class.name,
+        cache_key: key.to_s,
+        job_id: get_sidekiq_job_id,
+        message: message
+      }.compact
+    end
+  end
+end

ee/spec/services/geo/cache_invalidation_event_store_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Geo::CacheInvalidationEventStore do
+  include EE::GeoHelpers
+
+  set(:secondary_node) { create(:geo_node) }
+
+  let(:cache_key) { 'cache-key' }
+
+  subject { described_class.new(cache_key) }
+
+  describe '#create' do
+    it_behaves_like 'a Geo event store', Geo::CacheInvalidationEvent
+
+    context 'when running on a primary node' do
+      before do
+        stub_primary_node
+      end
+
+      it 'tracks the cache key that should be invalidated' do
+        subject.create!
+
+        expect(Geo::CacheInvalidationEvent.last).to have_attributes(key: cache_key)
+      end
+
+      it 'logs an error message when event creation fail' do
+        subject = described_class.new(nil)
+
+        expected_message = {
+          class: described_class.name,
+          cache_key: '',
+          message: 'Cache invalidation event could not be created',
+          error: "Validation failed: Key can't be blank"
+        }
+
+        expect(Gitlab::Geo::Logger).to receive(:error)
+          .with(expected_message).and_call_original
+
+        subject.create!
+      end
+    end
+  end
+end