Class: FileWatch::TailMode::Processor

Inherits:
Object
  • Object
show all
Includes:
LogStash::Util::Loggable
Defined in:
lib/filewatch/tail_mode/processor.rb

Overview

Must handle

:create_initial - file is discovered and we have no record of it in the sincedb
:create - file is discovered and we have seen it before in the sincedb
:grow   - file has more content
:shrink - file has less content
:delete   - file can't be read
:timeout - file is closable
:unignore - file was ignored, but have now received new content

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(settings) ⇒ Processor

Returns a new instance of Processor.



26
27
28
29
 
# File 'lib/filewatch/tail_mode/processor.rb', line 26

def initialize(settings)
  @settings = settings
  @deletable_filepaths = []
end

Instance Attribute Details

#deletable_filepaths ⇒ Object (readonly)

Returns the value of attribute deletable_filepaths.



24
25
26
 
# File 'lib/filewatch/tail_mode/processor.rb', line 24

def deletable_filepaths
  @deletable_filepaths
end

#watch ⇒ Object (readonly)

Returns the value of attribute watch.



24
25
26
 
# File 'lib/filewatch/tail_mode/processor.rb', line 24

def watch
  @watch
end

Instance Method Details

#add_watch(watch) ⇒ Object 



31
32
33
34
 
# File 'lib/filewatch/tail_mode/processor.rb', line 31

def add_watch(watch)
  @watch = watch
  self
end

#common_deleted_reaction(watched_file, action) ⇒ Object 



197
198
199
200
201
202
203
 
# File 'lib/filewatch/tail_mode/processor.rb', line 197

def common_deleted_reaction(watched_file, action)
  # file has gone away or we can't read it anymore.
  watched_file.unwatch
  delete(watched_file)
  deletable_filepaths << watched_file.path
  logger.debug("#{action} - stat failed: #{watched_file.path}, removing from collection")
end

#common_error_reaction(path, error, action) ⇒ Object 



205
206
207
 
# File 'lib/filewatch/tail_mode/processor.rb', line 205

def common_error_reaction(path, error, action)
  logger.error("#{action} - other error #{path}: (#{error.message}, #{error.backtrace.take(8).inspect})")
end

#create(watched_file) ⇒ Object 



46
47
48
 
# File 'lib/filewatch/tail_mode/processor.rb', line 46

def create(watched_file)
  @create.handle(watched_file)
end

#create_initial(watched_file) ⇒ Object 



50
51
52
 
# File 'lib/filewatch/tail_mode/processor.rb', line 50

def create_initial(watched_file)
  @create_initial.handle(watched_file)
end

#delete(watched_file) ⇒ Object 



62
63
64
 
# File 'lib/filewatch/tail_mode/processor.rb', line 62

def delete(watched_file)
  @delete.handle(watched_file)
end

#grow(watched_file) ⇒ Object 



54
55
56
 
# File 'lib/filewatch/tail_mode/processor.rb', line 54

def grow(watched_file)
  @grow.handle(watched_file)
end

#initialize_handlers(sincedb_collection, observer) ⇒ Object 



36
37
38
39
40
41
42
43
44
 
# File 'lib/filewatch/tail_mode/processor.rb', line 36

def initialize_handlers(sincedb_collection, observer)
  @create_initial = Handlers::CreateInitial.new(sincedb_collection, observer, @settings)
  @create = Handlers::Create.new(sincedb_collection, observer, @settings)
  @grow = Handlers::Grow.new(sincedb_collection, observer, @settings)
  @shrink = Handlers::Shrink.new(sincedb_collection, observer, @settings)
  @delete = Handlers::Delete.new(sincedb_collection, observer, @settings)
  @timeout = Handlers::Timeout.new(sincedb_collection, observer, @settings)
  @unignore = Handlers::Unignore.new(sincedb_collection, observer, @settings)
end

#process_active(watched_files) ⇒ Object 



161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
 
# File 'lib/filewatch/tail_mode/processor.rb', line 161

def process_active(watched_files)
  logger.debug("Active processing")
  # Handles watched_files in the active state.
  # it has been read once - unless they were empty at the time
  watched_files.select {|wf| wf.active? }.each do |watched_file|
    path = watched_file.path
    begin
      watched_file.restat
    rescue Errno::ENOENT
      # file has gone away or we can't read it anymore.
      common_deleted_reaction(watched_file, "Active")
      next
    rescue => e
      common_error_reaction(path, e, "Active")
      next
    end
    break if watch.quit?
    if watched_file.grown?
      logger.debug("Active - file grew: #{path}: new size is #{watched_file.last_stat_size}, old size #{watched_file.bytes_read}")
      grow(watched_file)
    elsif watched_file.shrunk?
      # we don't update the size here, its updated when we actually read
      logger.debug("Active - file shrunk #{path}: new size is #{watched_file.last_stat_size}, old size #{watched_file.bytes_read}")
      shrink(watched_file)
    else
      # same size, do nothing
    end
    # can any active files be closed to make way for waiting files?
    if watched_file.file_closable?
      logger.debug("Watch each: active: file expired: #{path}")
      timeout(watched_file)
      watched_file.close
    end
  end
end

#process_closed(watched_files) ⇒ Object 



74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
 
# File 'lib/filewatch/tail_mode/processor.rb', line 74

def process_closed(watched_files)
  logger.debug("Closed processing")
  # Handles watched_files in the closed state.
  # if its size changed it is put into the watched state
  watched_files.select {|wf| wf.closed? }.each do |watched_file|
    path = watched_file.path
    begin
      watched_file.restat
      if watched_file.size_changed?
        # if the closed file changed, move it to the watched state
        # not to active state because we want to respect the active files window.
        watched_file.watch
      end
    rescue Errno::ENOENT
      # file has gone away or we can't read it anymore.
      common_deleted_reaction(watched_file, "Closed")
    rescue => e
      common_error_reaction(path, e, "Closed")
    end
    break if watch.quit?
  end
end

#process_ignored(watched_files) ⇒ Object 



97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
 
# File 'lib/filewatch/tail_mode/processor.rb', line 97

def process_ignored(watched_files)
  logger.debug("Ignored processing")
  # Handles watched_files in the ignored state.
  # if its size changed:
  #   put it in the watched state
  #   invoke unignore
  watched_files.select {|wf| wf.ignored? }.each do |watched_file|
    path = watched_file.path
    begin
      watched_file.restat
      if watched_file.size_changed?
        watched_file.watch
        unignore(watched_file)
      end
    rescue Errno::ENOENT
      # file has gone away or we can't read it anymore.
      common_deleted_reaction(watched_file, "Ignored")
    rescue => e
      common_error_reaction(path, e, "Ignored")
    end
    break if watch.quit?
  end
end

#process_watched(watched_files) ⇒ Object 



121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
 
# File 'lib/filewatch/tail_mode/processor.rb', line 121

def process_watched(watched_files)
  logger.debug("Watched processing")
  # Handles watched_files in the watched state.
  # for a slice of them:
  #   move to the active state
  #   and we allow the block to open the file and create a sincedb collection record if needed
  #   some have never been active and some have
  #   those that were active before but are watched now were closed under constraint

  # how much of the max active window is available
  to_take = @settings.max_active - watched_files.count{|wf| wf.active?}
  if to_take > 0
    watched_files.select {|wf| wf.watched?}.take(to_take).each do |watched_file|
      path = watched_file.path
      begin
        watched_file.restat
        watched_file.activate
        if watched_file.initial?
          create_initial(watched_file)
        else
          create(watched_file)
        end
      rescue Errno::ENOENT
        # file has gone away or we can't read it anymore.
        common_deleted_reaction(watched_file, "Watched")
      rescue => e
        common_error_reaction(path, e, "Watched")
      end
      break if watch.quit?
    end
  else
    now = Time.now.to_i
    if (now - watch.lastwarn_max_files) > MAX_FILES_WARN_INTERVAL
      waiting = watched_files.size - @settings.max_active
      logger.warn(@settings.max_warn_msg + ", files yet to open: #{waiting}")
      watch.lastwarn_max_files = now
    end
  end
end

#shrink(watched_file) ⇒ Object 



58
59
60
 
# File 'lib/filewatch/tail_mode/processor.rb', line 58

def shrink(watched_file)
  @shrink.handle(watched_file)
end

#timeout(watched_file) ⇒ Object 



66
67
68
 
# File 'lib/filewatch/tail_mode/processor.rb', line 66

def timeout(watched_file)
  @timeout.handle(watched_file)
end

#unignore(watched_file) ⇒ Object 



70
71
72
 
# File 'lib/filewatch/tail_mode/processor.rb', line 70

def unignore(watched_file)
  @unignore.handle(watched_file)
end