Add log throttling in files based on group rules

lib/fluent/plugin/in_tail.rb

@@ -24,6 +24,7 @@
 require 'fluent/variable_store'
 require 'fluent/capability'
 require 'fluent/plugin/in_tail/position_file'
+require 'fluent/plugin/in_tail/group_watch'
 
 if Fluent.windows?
   require_relative 'file_wrapper'
@@ -33,6 +34,8 @@
 
 module Fluent::Plugin
   class TailInput < Fluent::Plugin::Input
+    include GroupWatch
+
     Fluent::Plugin.register_input('tail', self)
 
     helpers :timer, :event_loop, :parser, :compat_parameters
@@ -406,6 +409,8 @@ def setup_watcher(target_info, pe)
         event_loop_attach(watcher)
       end
 
+      tw.group_watcher = add_path_to_group_watcher(target_info.path)
+
       tw
     rescue => e
       if tw
@@ -461,6 +466,8 @@ def start_watchers(targets_info)
 
     def stop_watchers(targets_info, immediate: false, unwatched: false, remove_watcher: true)
       targets_info.each_value { |target_info|
+        remove_path_from_group_watcher(target_info.path)
+
         if remove_watcher
           tw = @tails.delete(target_info)
         else
@@ -542,18 +549,19 @@ def detach_watcher(tw, ino, close_io = true)
       end
     end
 
+    def throttling_is_enabled?(tw)
+      return true if @read_bytes_limit_per_second > 0
+      return true if tw.group_watcher && tw.group_watcher.limit >= 0
+      false
+    end
+
     def detach_watcher_after_rotate_wait(tw, ino)
       # Call event_loop_attach/event_loop_detach is high-cost for short-live object.
       # If this has a problem with large number of files, use @_event_loop directly instead of timer_execute.
       if @open_on_every_update
         # Detach now because it's already closed, waiting it doesn't make sense.
         detach_watcher(tw, ino)
-      elsif @read_bytes_limit_per_second < 0
-        # throttling isn't enabled, just wait @rotate_wait
-        timer_execute(:in_tail_close_watcher, @rotate_wait, repeat: false) do
-          detach_watcher(tw, ino)
-        end
-      else
+      elsif throttling_is_enabled?(tw)
         # When the throttling feature is enabled, it might not reach EOF yet.
         # Should ensure to read all contents before closing it, with keeping throttling.
         start_time_to_wait = Fluent::Clock.now
@@ -564,6 +572,11 @@ def detach_watcher_after_rotate_wait(tw, ino)
             detach_watcher(tw, ino)
           end
         end
+      else
+        # when the throttling feature isn't enabled, just wait @rotate_wait
+        timer_execute(:in_tail_close_watcher, @rotate_wait, repeat: false) do
+          detach_watcher(tw, ino)
+        end
       end
     end
 
@@ -775,6 +788,7 @@ def initialize(target_info, pe, log, read_from_head, follow_inodes, update_watch
       attr_reader :line_buffer_timer_flusher
       attr_accessor :unwatched  # This is used for removing position entry from PositionFile
       attr_reader :watchers
+      attr_accessor :group_watcher
 
       def tag
         @parsed_tag ||= @path.tr('/', '.').gsub(/\.+/, '.').gsub(/^\./, '')
@@ -997,6 +1011,10 @@ def initialize(watcher, path:, read_lines_limit:, read_bytes_limit_per_second:,
           @log.info "following tail of #{@path}"
         end
 
+        def group_watcher
+          @watcher.group_watcher
+        end
+
         def on_notify
           @notify_mutex.synchronize { handle_notify }
         end
@@ -1054,6 +1072,7 @@ def should_shutdown_now?
 
         def handle_notify
           return if limit_bytes_per_second_reached?
+          return if group_watcher&.limit_lines_reached?(@path)
 
           with_io do |io|
             begin
@@ -1063,17 +1082,26 @@ def handle_notify
                 begin
                   while true
                     @start_reading_time ||= Fluent::Clock.now
+                    group_watcher&.update_reading_time(@path)
+
                     data = io.readpartial(BYTES_TO_READ, @iobuf)
                     @eof = false
                     @number_bytes_read += data.bytesize
                     @fifo << data
+
+                    n_lines_before_read = @lines.size
                     @fifo.read_lines(@lines)
+                    group_watcher&.update_lines_read(@path, @lines.size - n_lines_before_read)
 
-                    if limit_bytes_per_second_reached? || should_shutdown_now?
+                    group_watcher_limit = group_watcher&.limit_lines_reached?(@path)
+                    @log.debug "Reading Limit exceeded #{@path} #{group_watcher.number_lines_read}" if group_watcher_limit
+
+                    if group_watcher_limit || limit_bytes_per_second_reached? || should_shutdown_now?
                       # Just get out from tailing loop.
                       read_more = false
                       break
                     end
+
                     if @lines.size >= @read_lines_limit
                       # not to use too much memory in case the file is very large
                       read_more = true

lib/fluent/plugin/in_tail/group_watch.rb

@@ -0,0 +1,204 @@
+#
+# Fluentd
+#
+#    Licensed under the Apache License, Version 2.0 (the "License");
+#    you may not use this file except in compliance with the License.
+#    You may obtain a copy of the License at
+#
+#        http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS,
+#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#    See the License for the specific language governing permissions and
+#    limitations under the License.
+#
+
+require 'fluent/plugin/input'
+
+module Fluent::Plugin
+  class TailInput < Fluent::Plugin::Input
+    module GroupWatchParams
+      include Fluent::Configurable
+
+      DEFAULT_KEY = /.*/
+      DEFAULT_LIMIT = -1
+      REGEXP_JOIN = "_"
+
+      config_section :group, param_name: :group, required: false, multi: false do
+        desc 'Regex for extracting group\'s metadata'
+        config_param :pattern,
+                     :regexp,
+                     default: /^\/var\/log\/containers\/(?<podname>[a-z0-9]([-a-z0-9]*[a-z0-9])?(\/[a-z0-9]([-a-z0-9]*[a-z0-9])?)*)_(?<namespace>[^_]+)_(?<container>.+)-(?<docker_id>[a-z0-9]{64})\.log$/
+
+        desc 'Period of time in which the group_line_limit is applied'
+        config_param :rate_period, :time, default: 5
+
+        config_section :rule, param_name: :rule, required: true, multi: true do
+          desc 'Key-value pairs for grouping'
+          config_param :match, :hash, value_type: :regexp, default: { namespace: [DEFAULT_KEY], podname: [DEFAULT_KEY] }
+          desc 'Maximum number of log lines allowed per group over a period of rate_period'
+          config_param :limit, :integer, default: DEFAULT_LIMIT
+        end
+      end
+    end
+
+    module GroupWatch
+      def self.included(mod)
+        mod.include GroupWatchParams
+      end
+
+      attr_reader :group_watchers, :default_group_key
+
+      def initialize
+        super
+        @group_watchers = {}
+        @group_keys = nil
+        @default_group_key = nil
+      end
+
+      def configure(conf)
+        super
+
+        unless @group.nil?
+          ## Ensuring correct time period syntax
+          @group.rule.each { |rule|
+            raise "Metadata Group Limit >= DEFAULT_LIMIT" unless rule.limit >= GroupWatchParams::DEFAULT_LIMIT
+          }
+
+          @group_keys = Regexp.compile(@group.pattern).named_captures.keys
+          @default_group_key = ([GroupWatchParams::DEFAULT_KEY] * @group_keys.length).join(GroupWatchParams::REGEXP_JOIN)
+
+          ## Ensures that "specific" rules (with larger number of `rule.match` keys)
+          ## have a higher priority against "generic" rules (with less number of `rule.match` keys).
+          ## This will be helpful when a file satisfies more than one rule.
+          @group.rule.sort_by! { |rule| -rule.match.length() }
+          construct_groupwatchers
+          @group_watchers[@default_group_key] ||= GroupWatcher.new(@group.rate_period, GroupWatchParams::DEFAULT_LIMIT)
+        end
+      end
+
+      def add_path_to_group_watcher(path)
+        return nil if @group.nil?
+        group_watcher = find_group_from_metadata(path)
+        group_watcher.add(path) unless group_watcher.include?(path)
+        group_watcher
+      end
+
+      def remove_path_from_group_watcher(path)
+        return if @group.nil?
+        group_watcher = find_group_from_metadata(path)
+        group_watcher.delete(path)
+      end
+
+      def construct_group_key(named_captures)
+        match_rule = []
+        @group_keys.each { |key|
+          match_rule.append(named_captures.fetch(key, GroupWatchParams::DEFAULT_KEY))
+        }
+        match_rule = match_rule.join(GroupWatchParams::REGEXP_JOIN)
+
+        match_rule
+      end
+
+      def construct_groupwatchers
+        @group.rule.each { |rule|
+          match_rule = construct_group_key(rule.match)
+          @group_watchers[match_rule] ||= GroupWatcher.new(@group.rate_period, rule.limit)
+        }
+      end
+
+      def find_group(metadata)
+        metadata_key = construct_group_key(metadata)
+        gw_key = @group_watchers.keys.find { |regexp| metadata_key.match?(regexp) && regexp != @default_group_key }
+        gw_key ||= @default_group_key
+
+        @group_watchers[gw_key]
+      end
+
+      def find_group_from_metadata(path)
+        begin
+          metadata = @group.pattern.match(path).named_captures
+          group_watcher = find_group(metadata)
+        rescue
+          log.warn "Cannot find group from metadata, Adding file in the default group"
+          group_watcher = @group_watchers[@default_group_key]
+        end
+
+        group_watcher
+      end
+    end
+
+    class GroupWatcher
+      attr_accessor :current_paths, :limit, :number_lines_read, :start_reading_time, :rate_period
+
+      FileCounter = Struct.new(
+        :number_lines_read,
+        :start_reading_time,
+      )
+
+      def initialize(rate_period = 60, limit = -1)
+        @current_paths = {}
+        @rate_period = rate_period
+        @limit = limit
+      end
+
+      def add(path)
+        @current_paths[path] = FileCounter.new(0, nil)
+      end
+
+      def include?(path)
+        @current_paths.key?(path)
+      end
+
+      def size
+        @current_paths.size
+      end
+
+      def delete(path)
+        @current_paths.delete(path)
+      end
+
+      def update_reading_time(path)
+        @current_paths[path].start_reading_time ||= Fluent::Clock.now
+      end
+
+      def update_lines_read(path, value)
+        @current_paths[path].number_lines_read += value
+      end
+
+      def reset_counter(path)
+        @current_paths[path].start_reading_time = nil
+        @current_paths[path].number_lines_read = 0
+      end
+
+      def time_spent_reading(path)
+        Fluent::Clock.now - @current_paths[path].start_reading_time
+      end
+
+      def limit_time_period_reached?(path)
+        time_spent_reading(path) < @rate_period
+      end
+
+      def limit_lines_reached?(path)
+        return true unless include?(path)
+        return true if @limit == 0
+
+        return false if @limit < 0
+        return false if @current_paths[path].number_lines_read < @limit / size
+
+        # update_reading_time(path)
+        if limit_time_period_reached?(path) # Exceeds limit
+          true
+        else # Does not exceed limit
+          reset_counter(path)
+          false
+        end
+      end
+
+      def to_s
+        super + " current_paths: #{@current_paths} rate_period: #{@rate_period} limit: #{@limit}"
+      end
+    end
+  end
+end

test/plugin/in_tail/test_io_handler.rb

@@ -21,12 +21,20 @@ class IntailIOHandlerTest < Test::Unit::TestCase
     @file.unlink rescue nil
   end
 
+  def create_target_info
+    Fluent::Plugin::TailInput::TargetInfo.new(@file.path, Fluent::FileWrapper.stat(@file.path).ino)
+  end
+
+  def create_watcher
+    Fluent::Plugin::TailInput::TailWatcher.new(create_target_info, nil, nil, nil, nil, nil, nil, nil, nil)
+  end
+
   test '#on_notify load file content and passed it to receive_lines method' do
     text = "this line is test\ntest line is test\n"
     @file.write(text)
     @file.close
 
-    watcher = 'watcher'
+    watcher = create_watcher
 
     update_pos = 0
 
@@ -61,7 +69,7 @@ class IntailIOHandlerTest < Test::Unit::TestCase
 
       update_pos = 0
 
-      watcher = 'watcher'
+      watcher = create_watcher
       stub(watcher).pe do
         pe = 'position_file'
         stub(pe).read_pos { 0 }
@@ -92,7 +100,7 @@ class IntailIOHandlerTest < Test::Unit::TestCase
 
       update_pos = 0
 
-      watcher = 'watcher'
+      watcher = create_watcher
       stub(watcher).pe do
         pe = 'position_file'
         stub(pe).read_pos { 0 }
@@ -118,7 +126,7 @@ class IntailIOHandlerTest < Test::Unit::TestCase
 
       update_pos = 0
 
-      watcher = 'watcher'
+      watcher = create_watcher
       stub(watcher).pe do
         pe = 'position_file'
         stub(pe).read_pos { 0 }