Class: FileWatch::Tail

Inherits:
Object
  • Object
show all
Defined in:
lib/filewatch/tail.rb

Defined Under Namespace

Classes: NoSinceDBPathGiven

Constant Summary collapse

OPEN_WARN_INTERVAL =

how often (in seconds) we @logger.warn a failed file open, per path.

ENV["FILEWATCH_OPEN_WARN_INTERVAL"] ?
ENV["FILEWATCH_OPEN_WARN_INTERVAL"].to_i : 300

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(opts = {}) ⇒ Tail

Returns a new instance of Tail.



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# File 'lib/filewatch/tail.rb', line 20

def initialize(opts={})
  if opts[:logger]
    @logger = opts[:logger]
  else
    @logger = Logger.new(STDERR)
    @logger.level = Logger::DEBUG
  end
  @evict = nil
  @files = {}
  @locked = Hash.new { |h, k| h[k] = false }
  @changed = Hash.new { |h, k| h[k] = 0 }
  @lastwarn = Hash.new { |h, k| h[k] = 0 }
  @buffers = {}
  @sincedb = {}
  @sincedb_last_write = Time.now.to_i
  @sincedb_write_pending = false
  @sincedb_writing = false
  @statcache = {}
  @opts = {
    :ignore_before => 0, # Ignore files last modified before this timestamp
    :eviction_interval => 300, # Let go of file handles after five minutes
    :sincedb_write_interval => 10,
    :stat_interval => 1,
    :discover_interval => 5,
    :exclude => [],
    :start_new_files_at => :end,
    :follow_only_path => false
  }.merge(opts)
  if !@opts.include?(:sincedb_path)
    @opts[:sincedb_path] = File.join(ENV["HOME"], ".sincedb") if ENV.include?("HOME")
    @opts[:sincedb_path] = ENV["SINCEDB_PATH"] if ENV.include?("SINCEDB_PATH")
  end
  if !@opts.include?(:sincedb_path)
    raise NoSinceDBPathGiven.new("No HOME or SINCEDB_PATH set in environment. I need one of these set so I can keep track of the files I am following.")
  end
  @watch = FileWatch::Watch.new \
    logger: @opts[:logger],
    ignore_before: @opts[:ignore_before]
  @watch.exclude(@opts[:exclude])
  _start_eviction
  _sincedb_open
end

Instance Attribute Details

#logger ⇒ Object

Returns the value of attribute logger.



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# File 'lib/filewatch/tail.rb', line 15

def logger
  @logger
end

Instance Method Details

#quit ⇒ Object 



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# File 'lib/filewatch/tail.rb', line 309

def quit
  @evict && @evict.kill
  @watch.quit
end

#sincedb_write(reason = nil) ⇒ Object 



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# File 'lib/filewatch/tail.rb', line 214

def sincedb_write(reason=nil)
  @logger.debug("caller requested sincedb write (#{reason})")
  _sincedb_write(true)  # since this is an external request, force the write
end

#subscribe(&block) ⇒ Object 



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# File 'lib/filewatch/tail.rb', line 75

def subscribe(&block)
  # subscribe(stat_interval = 1, discover_interval = 5, &block)
  @watch.subscribe(@opts[:stat_interval],
                   @opts[:discover_interval]) do |event, path|
    case event
    when :create, :create_initial
      if !@files[path].nil?
        @logger.debug("#{event} for #{path}: already exists in @files")
        next
      end
      if _open_file(path, event)
        _read_file(path, &block)
      end
    when :modify
      if @files[path].nil?
        @logger.debug(":modify for #{path}, does not exist in @files")
        if _open_file(path, event)
          _read_file(path, &block)
        end
      else
        _read_file(path, &block)
      end
    when :delete
      @logger.debug(":delete for #{path}, deleted from @files")
      # if File::exist?(path) # Rotated
      #   if @files[path].nil?
      #     _open_file(path, event)
      #   end
      #   _read_file(path, &block)
      # end
      @files.delete(path).close rescue nil
      @statcache.delete(path)
    when :noupdate
      # @logger.debug(":noupdate for #{path}, from @files")
      _sincedb_write_if_pending   # will check to see if sincedb_write requests are pending 
    else
      @logger.warn("unknown event type #{event} for #{path}")
    end
  end # @watch.subscribe
end

#tail(path) ⇒ Object 



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# File 'lib/filewatch/tail.rb', line 70

def tail(path)
  @watch.watch(path)
end