out_copy: support ignore_error in store section

lib/fluent/plugin/multi_output.rb

@@ -29,6 +29,7 @@ class MultiOutput < Base
       helpers :event_emitter # to get router from agent, which will be supplied to child plugins
 
       config_section :store, param_name: :stores, multi: true, required: true do
+        config_argument :arg, :string, default: ''
         config_param :@type, :string, default: nil
       end
 

lib/fluent/plugin/out_copy.rb

@@ -25,6 +25,21 @@ class CopyOutput < MultiOutput
     desc 'If true, pass different record to each `store` plugin.'
     config_param :deep_copy, :bool, default: false
 
+    attr_reader :ignore_errors
+
+    def initialize
+      super
+      @ignore_errors = []
+    end
+
+    def configure(conf)
+      super
+
+      @stores.each { |store|
+        @ignore_errors << (store.arg == 'ignore_error')
+      }
+    end
+
     def multi_workers_ready?
       true
     end
@@ -38,8 +53,16 @@ def process(tag, es)
         es = m
       end
 
-      outputs.each do |output|
-        output.emit_events(tag, @deep_copy ? es.dup : es)
+      outputs.each_with_index do |output, i|
+        begin
+          output.emit_events(tag, @deep_copy ? es.dup : es)
+        rescue => e
+          if @ignore_errors[i]
+            log.error "ignore emit error", error: e
+          else
+            raise e
+          end
+        end
       end
     end
   end

test/plugin/test_out_copy.rb

@@ -156,5 +156,36 @@ def test_deep_copy_controls_shallow_or_deep_copied(data)
       end
     end
   end
+
+  IGNORE_ERROR_CONFIG = %[
+    <store ignore_error>
+      @type test
+      name c0
+    </store>
+    <store ignore_error>
+      @type test
+      name c1
+    </store>
+    <store>
+      @type test
+      name c2
+    </store>
+  ]
+
+  def test_ignore_error
+    d = create_driver(IGNORE_ERROR_CONFIG)
+
+    # override to raise an error
+    d.instance.outputs[0].define_singleton_method(:process) do |tag, es|
+      raise ArgumentError, 'Failed'
+    end
+
+    time = Time.parse("2011-01-02 13:14:15 UTC").to_i
+    assert_nothing_raised do
+      d.run(default_tag: 'test') do
+        d.feed(time, {"a"=>1})
+      end
+    end
+  end
 end