only start monitoring pipeline after valid license (#10106)

Avoid unecessary logging errors and resource usage by only starting
the monitoring pipeline if we can validate the license.

x-pack/lib/monitoring/internal_pipeline_source.rb

@@ -3,20 +3,91 @@
 # you may not use this file except in compliance with the Elastic License.
 
 require "logstash/config/source/base"
+require 'license_checker/licensed'
+require 'helpers/elasticsearch_options'
 
 module LogStash module Monitoring
   class InternalPipelineSource < LogStash::Config::Source::Base
-    def initialize(pipeline_config)
+    include LogStash::LicenseChecker::Licensed
+    include LogStash::Helpers::ElasticsearchOptions
+    include LogStash::Util::Loggable
+    VALID_LICENSES = %w(basic trial standard gold platinum)
+    FEATURE = 'monitoring'
+
+    def initialize(pipeline_config, agent)
       super(pipeline_config.settings)
       @pipeline_config = pipeline_config
+      @settings = LogStash::SETTINGS.clone
+      @agent = agent
+      @es_options = es_options_from_settings_or_modules(FEATURE, @settings)
+      setup_license_checker(FEATURE)
     end
 
     def pipeline_configs
-      return @pipeline_config
+      @pipeline_config
     end
 
     def match?
-      true
+      valid_basic_license?
     end
+
+    def update_license_state(xpack_info)
+      return if valid_basic_license?
+      super(xpack_info) if xpack_info
+      if valid_basic_license?
+        logger.info("Validated license for monitoring. Enabling monitoring pipeline.")
+        enable_monitoring()
+      end
+    end
+
+    private
+    def valid_basic_license?
+      @license_state ? license_check : false
+    end
+
+    def enable_monitoring
+      @agent.converge_state_and_update
+    end
+
+    def populate_license_state(xpack_info)
+      if xpack_info.failed?
+        {
+            :state => :error,
+            :log_level => :error,
+            :log_message => "Failed to fetch X-Pack information from Elasticsearch. This is likely due to failure to reach a live Elasticsearch cluster."
+        }
+      elsif !xpack_info.installed?
+        {
+            :state => :error,
+            :log_level => :error,
+            :log_message => "X-Pack is installed on Logstash but not on Elasticsearch. Please install X-Pack on Elasticsearch to use the monitoring feature. Other features may be available."
+        }
+      elsif !xpack_info.license_available?
+        {
+            :state => :error,
+            :log_level => :error,
+            :log_message => 'Monitoring is not available: License information is currently unavailable. Please make sure you have added your production elasticsearch connection info in the xpack.monitoring.elasticsearch settings.'
+        }
+      elsif !xpack_info.license_one_of?(VALID_LICENSES)
+        {
+            :state => :error,
+            :log_level => :error,
+            :log_message => "Monitoring is not available: #{xpack_info.license_type} is not a valid license for this feature."
+        }
+      elsif !xpack_info.license_active?
+        {
+            :state => :ok,
+            :log_level => :warn,
+            :log_message => 'Monitoring requires a valid license. You can continue to monitor Logstash, but please contact your administrator to update your license'
+        }
+      else
+        unless xpack_info.feature_enabled?(FEATURE)
+          logger.warn('Monitoring installed and enabled in Logstash, but not enabled in Elasticsearch')
+        end
+
+        { :state => :ok, :log_level => :info, :log_message => 'Monitoring License OK' }
+      end
+    end
+
   end
 end end