Add buf_file_single plugin

lib/fluent/plugin/buf_file_single.rb

@@ -0,0 +1,211 @@
+#
+# 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 'fileutils'
+
+require 'fluent/plugin/buffer'
+require 'fluent/plugin/buffer/file_single_chunk'
+require 'fluent/system_config'
+
+module Fluent
+  module Plugin
+    class FileSingleBuffer < Fluent::Plugin::Buffer
+      Plugin.register_buffer('file_single', self)
+
+      include SystemConfig::Mixin
+
+      DEFAULT_CHUNK_LIMIT_SIZE = 256 * 1024 * 1024        # 256MB
+      DEFAULT_TOTAL_LIMIT_SIZE =  64 * 1024 * 1024 * 1024 #  64GB
+
+      PATH_SUFFIX = ".#{Fluent::Plugin::Buffer::FileSingleChunk::PATH_EXT}"
+      DIR_PERMISSION = 0755
+
+      desc 'The path where buffer chunks are stored.'
+      config_param :path, :string, default: nil
+      desc 'Calculate the number of record in chunk during resume'
+      config_param :calc_num_records, :bool, default: true
+      desc 'The format of chunk. This is used to calculate the number of record'
+      config_param :chunk_format, :enum, list: [:msgpack, :text, :auto], default: :auto
+
+      config_set_default :chunk_limit_size, DEFAULT_CHUNK_LIMIT_SIZE
+      config_set_default :total_limit_size, DEFAULT_TOTAL_LIMIT_SIZE
+
+      desc 'The permission of chunk file. If no specified, <system> setting or 0644 is used'
+      config_param :file_permission, :string, default: nil
+      desc 'The permission of chunk directory. If no specified, <system> setting or 0755 is used'
+      config_param :dir_permission, :string, default: nil
+
+      @@buffer_paths = {}
+
+      def initialize
+        super
+
+        @multi_workers_available = false
+        @additional_resume_path = nil
+      end
+
+      def configure(conf)
+        super
+
+        if @chunk_format == :auto
+          @chunk_format = owner.formatted_to_msgpack_binary? ? :msgpack : :text
+        end
+
+        @key_in_path = nil
+        if owner.chunk_keys.empty?
+          log.debug "use event tag for buffer key"
+        else
+          if owner.chunk_key_tag
+            raise Fluent::ConfigError, "chunk keys must be tag or one field"
+          elsif owner.chunk_keys.size > 1
+            raise Fluent::ConfigError, "2 or more chunk keys is not allowed"
+          else
+            @key_in_path = owner.chunk_keys.first.to_sym
+          end
+        end
+
+        multi_workers_configured = owner.system_config.workers > 1
+        using_plugin_root_dir = false
+        unless @path
+          if root_dir = owner.plugin_root_dir
+            @path = File.join(root_dir, 'buffer')
+            using_plugin_root_dir = true # plugin_root_dir path contains worker id
+          else
+            raise Fluent::ConfigError, "buffer path is not configured. specify 'path' in <buffer>"
+          end
+        end
+
+        type_of_owner = Plugin.lookup_type_from_class(@_owner.class)
+        if @@buffer_paths.has_key?(@path) && !called_in_test?
+          type_using_this_path = @@buffer_paths[@path]
+          raise Fluent::ConfigError, "Other '#{type_using_this_path}' plugin already uses same buffer path: type = #{type_of_owner}, buffer path = #{@path}"
+        end
+
+        @@buffer_paths[@path] = type_of_owner
+
+        specified_directory_exists = File.exist?(@path) && File.directory?(@path)
+        unexisting_path_for_directory = !File.exist?(@path) && [email protected]?('.*')
+
+        if specified_directory_exists || unexisting_path_for_directory # directory
+          if using_plugin_root_dir || !multi_workers_configured
+            @path = File.join(@path, "fsb.*#{PATH_SUFFIX}")
+          else
+            @path = File.join(@path, "worker#{fluentd_worker_id}", "fsb.*#{PATH_SUFFIX}")
+            if fluentd_worker_id == 0
+              # worker 0 always checks unflushed buffer chunks to be resumed (might be created while non-multi-worker configuration)
+              @additional_resume_path = File.join(File.expand_path("../../", @path), "fsb.*#{PATH_SUFFIX}")
+            end
+          end
+          @multi_workers_available = true
+        else # specified path is file path
+          if File.basename(@path).include?('.*.')
+            new_path = File.join(File.dirname(@path), "fsb.*#{PATH_SUFFIX}")
+            log.warn "file_single doesn't allow user specified 'prefix.*.suffix' style path. Use '#{new_path}' for file instead: #{@path}"
+            @path = new_path
+          elsif File.basename(@path).end_with?('.*')
+            @path = @path + PATH_SUFFIX
+          else
+            # existing file will be ignored
+            @path = @path + ".*#{PATH_SUFFIX}"
+          end
+          @multi_workers_available = false
+        end
+
+        @dir_permission = if @dir_permission
+                            @dir_permission.to_i(8)
+                          else
+                            system_config.dir_permission || DIR_PERMISSION
+                          end
+      end
+
+      # This method is called only when multi worker is configured
+      def multi_workers_ready?
+        unless @multi_workers_available
+          log.error "file_single buffer with multi workers should be configured to use directory 'path', or system root_dir and plugin id"
+        end
+        @multi_workers_available
+      end
+
+      def start
+        FileUtils.mkdir_p(File.dirname(@path), mode: @dir_permission)
+
+        super
+      end
+
+      def persistent?
+        true
+      end
+
+      def resume
+        stage = {}
+        queue = []
+
+        patterns = [@path]
+        patterns.unshift @additional_resume_path if @additional_resume_path
+        Dir.glob(patterns) do |path|
+          next unless File.file?(path)
+
+          log.debug { "restoring buffer file: path = #{path}" }
+
+          m = new_metadata() # this metadata will be updated in FileSingleChunk.new
+          mode = Fluent::Plugin::Buffer::FileSingleChunk.assume_chunk_state(path)
+          if mode == :unknown
+            log.debug "unknown state chunk found", path: path
+            next
+          end
+
+          begin
+            chunk = Fluent::Plugin::Buffer::FileSingleChunk.new(m, path, mode, @key_in_path)
+            chunk.restore_size(@chunk_format) if @calc_num_records
+          rescue Fluent::Plugin::Buffer::FileSingleChunk::FileChunkError => e
+            handle_broken_files(path, mode, e)
+            next
+          end
+
+          case chunk.state
+          when :staged
+            stage[chunk.metadata] = chunk
+          when :queued
+            queue << chunk
+          end
+        end
+
+        queue.sort_by!(&:modified_at)
+
+        return stage, queue
+      end
+
+      def generate_chunk(metadata)
+        # FileChunk generates real path with unique_id
+        if @file_permission
+          chunk = Fluent::Plugin::Buffer::FileSingleChunk.new(metadata, @path, :create, @key_in_path, perm: @file_permission, compress: @compress)
+        else
+          chunk = Fluent::Plugin::Buffer::FileSingleChunk.new(metadata, @path, :create, @key_in_path, compress: @compress)
+        end
+
+        log.debug "Created new chunk", chunk_id: dump_unique_id_hex(chunk.unique_id), metadata: metadata
+
+        chunk
+      end
+
+      def handle_broken_files(path, mode, e)
+        log.error "found broken chunk file during resume. Delete corresponding files:", path: path, mode: mode, err_msg: e.message
+        # After support 'backup_dir' feature, these files are moved to backup_dir instead of unlink.
+        File.unlink(path) rescue nil
+      end
+    end
+  end
+end