remove multi_filter

lib/logstash/config/config_ast.rb

@@ -230,7 +230,7 @@ module LogStash; module Config; module AST
         return "start_input(#{variable_name})"
       when "filter"
         return <<-CODE
-          events = #{variable_name}.multi_filter(events)
+          #{variable_name}.filter(event) {|new_event| events << new_event }
         CODE
       when "output"
         return "#{variable_name}.handle(event)\n"

lib/logstash/filters/base.rb

@@ -146,24 +146,6 @@ class LogStash::Filters::Base < LogStash::Plugin
     raise "#{self.class}#filter must be overidden"
   end # def filter
 
-
-  # in 1.5.0 multi_filter is meant to be used in the generated filter function in LogStash::Config::AST::Plugin only
-  # and is temporary until we refactor the filter method interface to accept events list and return events list,
-  # just list in multi_filter see https://github.com/elastic/logstash/issues/2872.
-  # refactoring the filter method will mean updating all plugins which we want to avoid doing for 1.5.0.
-  #
-  # @param events [Array<LogStash::Event] list of events to filter
-  # @return [Array<LogStash::Event] filtered events and any new events generated by the filter
-  public
-  def multi_filter(events)
-    result = []
-    events.each do |event|
-      result << event
-      filter(event){|new_event| result << new_event}
-    end
-    result
-  end
-
   public
   def execute(event, &block)
     filter(event, &block)

spec/filters/base_spec.rb

@@ -24,24 +24,10 @@ describe LogStash::Filters::Base do
   end
 
   it "should provide class public API" do
-    [:register, :filter, :multi_filter, :execute, :threadsafe?, :filter_matched, :filter?, :teardown].each do |method|
+    [:register, :filter, :execute, :threadsafe?, :filter_matched, :filter?, :teardown].each do |method|
       expect(subject).to respond_to(method)
     end
   end
-
-  it "should multi_filter without new events" do
-    allow(subject).to receive(:filter) do |event, &block|
-      nil
-    end
-    expect(subject.multi_filter([:foo])).to eq([:foo])
-  end
-
-  it "should multi_filter with new events" do
-    allow(subject).to receive(:filter) do |event, &block|
-      block.call(:bar)
-    end
-    expect(subject.multi_filter([:foo])).to eq([:foo, :bar])
-  end
 end
 
 describe LogStash::Filters::NOOP do