Add admin dashboard checks for Elasticsearch version (#17863)

app/lib/admin/system_check/elasticsearch_check.rb

@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+class Admin::SystemCheck::ElasticsearchCheck < Admin::SystemCheck::BaseCheck
+  def pass?
+    return true unless Chewy.enabled?
+
+    running_version.present? && compatible_version?
+  end
+
+  def message
+    if running_version.present?
+      Admin::SystemCheck::Message.new(:elasticsearch_version_check, I18n.t('admin.system_checks.elasticsearch_version_check.version_comparison', running_version: running_version, required_version: required_version))
+    else
+      Admin::SystemCheck::Message.new(:elasticsearch_running_check)
+    end
+  end
+
+  private
+
+  def running_version
+    @running_version ||= begin
+      Chewy.client.info['version']['number']
+    rescue Faraday::ConnectionFailed
+      nil
+    end
+  end
+
+  def required_version
+    '7.x'
+  end
+
+  def compatible_version?
+    Gem::Version.new(running_version) >= Gem::Version.new(required_version)
+  end
+
+  def missing_queues
+    @missing_queues ||= Sidekiq::ProcessSet.new.reduce(SIDEKIQ_QUEUES) { |queues, process| queues - process['queues'] }
+  end
+end