plugin_helper: metrics: Manage plugin lifecycles via owner

Signed-off-by: Hiroshi Hatake <hatake@calyptia.com>

lib/fluent/plugin_helper/metrics.rb

@@ -28,8 +28,11 @@ module PluginHelper
     module Metrics
       include Fluent::SystemConfig::Mixin
 
+      attr_reader :_metrics # For tests.
+
       def initialize
         super
+        @_metrics_started = false
         @_metrics = {} # usage => metrics_state
       end
 
@@ -68,7 +71,52 @@ def metrics_create(namespace: "fluentd", subsystem: "metrics", name:, help_text:
         metrics
       end
 
+      def metrics_operate(method_name, &block)
+        @_metrics.each_pair do |key, m|
+          begin
+            block.call(s) if block_given?
+            m.__send__(method_name)
+          rescue => e
+            log.error "unexpected error while #{method_name}", key: key, metrics: m, error: e
+          end
+        end
+      end
+
+      def start
+        super
+
+        metrics_operate(:start)
+        @_metrics_started = true
+      end
+
+      def stop
+        super
+        # timer stops automatically in super
+        metrics_operate(:stop)
+      end
+
+      def before_shutdown
+        metrics_operate(:before_shutdown)
+        super
+      end
+
+      def shutdown
+        metrics_operate(:shutdown)
+        super
+      end
+
+      def after_shutdown
+        metrics_operate(:after_shutdown)
+        super
+      end
+
+      def close
+        metrics_operate(:close)
+        super
+      end
+
       def terminate
+        metrics_operate(:terminate)
         @_metrics = {}
         super
       end

test/plugin_helper/test_metrics.rb

@@ -0,0 +1,128 @@
+require_relative '../helper'
+require 'fluent/plugin_helper/metrics'
+require 'fluent/plugin/base'
+
+class MetricsTest < Test::Unit::TestCase
+  class Dummy < Fluent::Plugin::TestBase
+    helpers :metrics
+    def configure(conf)
+      super
+    end
+  end
+
+  setup do
+    @d = nil
+  end
+
+  teardown do
+    if @d
+      @d.stop unless @d.stopped?
+      @d.shutdown unless @d.shutdown?
+      @d.close unless @d.closed?
+      @d.terminate unless @d.terminated?
+    end
+  end
+
+  test 'can be initialized without any metrics at first' do
+    d = Dummy.new
+    assert_equal 0, d._metrics.size
+  end
+
+  test 'can be configured' do
+    d1 = Dummy.new
+    assert_nothing_raised do
+      d1.configure(config_element())
+    end
+    assert d1.plugin_id
+    assert d1.log
+  end
+
+  test 'creates metrics instances' do
+    d = Dummy.new
+    d.configure(config_element())
+    i = d.metrics_create(namespace: "fluentd_test", subsystem: "unit-test", name: "metrics1", help_text: "metrics testing")
+    assert{ i.is_a?(Fluent::Plugin::LocalMetrics) }
+    assert_true i.has_methods_for_counter
+    assert_false i.has_methods_for_gauge
+
+    d = Dummy.new
+    d.configure(config_element())
+    i = d.metrics_create(namespace: "fluentd_test", subsystem: "unit-test", name: "metrics2", help_text: "metrics testing", prefer_gauge: true)
+    assert{ i.is_a?(Fluent::Plugin::LocalMetrics) }
+    assert_false i.has_methods_for_counter
+    assert_true i.has_methods_for_gauge
+  end
+
+  test 'calls lifecycle methods for all plugin instances via owner plugin' do
+    @d = d = Dummy.new
+    d.configure(config_element())
+    i1 = d.metrics_create(namespace: "fluentd_test", subsystem: "unit-test", name: "metrics1", help_text: "metrics testing")
+    i2 = d.metrics_create(namespace: "fluentd_test", subsystem: "unit-test", name: "metrics2", help_text: "metrics testing", prefer_gauge: true)
+    i3 = d.metrics_create(namespace: "fluentd_test", subsystem: "unit-test", name: "metrics3", help_text: "metrics testing")
+    d.start
+
+    assert i1.started?
+    assert i2.started?
+    assert i3.started?
+
+    assert !i1.stopped?
+    assert !i2.stopped?
+    assert !i3.stopped?
+
+    d.stop
+
+    assert i1.stopped?
+    assert i2.stopped?
+    assert i3.stopped?
+
+    assert !i1.before_shutdown?
+    assert !i2.before_shutdown?
+    assert !i3.before_shutdown?
+
+    d.before_shutdown
+
+    assert i1.before_shutdown?
+    assert i2.before_shutdown?
+    assert i3.before_shutdown?
+
+    assert !i1.shutdown?
+    assert !i2.shutdown?
+    assert !i3.shutdown?
+
+    d.shutdown
+
+    assert i1.shutdown?
+    assert i2.shutdown?
+    assert i3.shutdown?
+
+    assert !i1.after_shutdown?
+    assert !i2.after_shutdown?
+    assert !i3.after_shutdown?
+
+    d.after_shutdown
+
+    assert i1.after_shutdown?
+    assert i2.after_shutdown?
+    assert i3.after_shutdown?
+
+    assert !i1.closed?
+    assert !i2.closed?
+    assert !i3.closed?
+
+    d.close
+
+    assert i1.closed?
+    assert i2.closed?
+    assert i3.closed?
+
+    assert !i1.terminated?
+    assert !i2.terminated?
+    assert !i3.terminated?
+
+    d.terminate
+
+    assert i1.terminated?
+    assert i2.terminated?
+    assert i3.terminated?
+  end
+end