| blob | 4c46278edd1268e37efb11e01d8064d8ba4093bf |
1 # frozen_string_literal: true
3 require_relative 'period'
5 class Logger
6 # Device used for logging messages.
7 class LogDevice
8 include Period
10 attr_reader :dev
11 attr_reader :filename
12 include MonitorMixin
14 def initialize(log = nil, shift_age: nil, shift_size: nil, shift_period_suffix: nil, binmode: false, reraise_write_errors: [])
15 @dev = @filename = @shift_age = @shift_size = @shift_period_suffix = nil
16 @binmode = binmode
17 @reraise_write_errors = reraise_write_errors
18 mon_initialize
19 set_dev(log)
20 if @filename
21 @shift_age = shift_age || 7
22 @shift_size = shift_size || 1048576
23 @shift_period_suffix = shift_period_suffix || '%Y%m%d'
25 unless @shift_age.is_a?(Integer)
26 base_time = @dev.respond_to?(:stat) ? @dev.stat.mtime : Time.now
27 @next_rotate_time = next_rotate_time(base_time, @shift_age)
28 end
29 end
30 end
32 def write(message)
33 handle_write_errors("writing") do
34 synchronize do
35 if @shift_age and @dev.respond_to?(:stat)
36 handle_write_errors("shifting") {check_shift_log}
37 end
38 handle_write_errors("writing") {@dev.write(message)}
39 end
40 end
41 end
43 def close
44 begin
45 synchronize do
46 @dev.close rescue nil
47 end
48 rescue Exception
49 @dev.close rescue nil
50 end
51 end
53 def reopen(log = nil)
54 # reopen the same filename if no argument, do nothing for IO
55 log ||= @filename if @filename
56 if log
57 synchronize do
58 if @filename and @dev
59 @dev.close rescue nil # close only file opened by Logger
60 @filename = nil
61 end
62 set_dev(log)
63 end
64 end
65 self
66 end
68 private
70 # :stopdoc:
72 MODE = File::WRONLY | File::APPEND
73 MODE_TO_OPEN = MODE | File::SHARE_DELETE | File::BINARY
74 MODE_TO_CREATE = MODE_TO_OPEN | File::CREAT | File::EXCL
76 def set_dev(log)
77 if log.respond_to?(:write) and log.respond_to?(:close)
78 @dev = log
79 if log.respond_to?(:path) and path = log.path
80 if File.exist?(path)
81 @filename = path
82 end
83 end
84 else
85 @dev = open_logfile(log)
86 @filename = log
87 end
88 end
90 if MODE_TO_OPEN == MODE
91 def fixup_mode(dev, filename)
92 dev
93 end
94 else
95 def fixup_mode(dev, filename)
96 return dev if @binmode
97 dev.autoclose = false
98 old_dev = dev
99 dev = File.new(dev.fileno, mode: MODE, path: filename)
100 old_dev.close
101 PathAttr.set_path(dev, filename) if defined?(PathAttr)
102 dev
103 end
104 end
106 def open_logfile(filename)
107 begin
108 dev = File.open(filename, MODE_TO_OPEN)
109 rescue Errno::ENOENT
110 create_logfile(filename)
111 else
112 dev = fixup_mode(dev, filename)
113 dev.sync = true
114 dev.binmode if @binmode
115 dev
116 end
117 end
119 def create_logfile(filename)
120 begin
121 logdev = File.open(filename, MODE_TO_CREATE)
122 logdev.flock(File::LOCK_EX)
123 logdev = fixup_mode(logdev, filename)
124 logdev.sync = true
125 logdev.binmode if @binmode
126 add_log_header(logdev)
127 logdev.flock(File::LOCK_UN)
128 logdev
129 rescue Errno::EEXIST
130 # file is created by another process
131 open_logfile(filename)
132 end
133 end
135 def handle_write_errors(mesg)
136 yield
137 rescue *@reraise_write_errors
138 raise
139 rescue
140 warn("log #{mesg} failed. #{$!}")
141 end
143 def add_log_header(file)
144 file.write(
145 "# Logfile created on %s by %s\n" % [Time.now.to_s, Logger::ProgName]
146 ) if file.size == 0
147 end
149 def check_shift_log
150 if @shift_age.is_a?(Integer)
151 # Note: always returns false if '0'.
152 if @filename && (@shift_age > 0) && (@dev.stat.size > @shift_size)
153 lock_shift_log { shift_log_age }
154 end
155 else
156 now = Time.now
157 if now >= @next_rotate_time
158 @next_rotate_time = next_rotate_time(now, @shift_age)
159 lock_shift_log { shift_log_period(previous_period_end(now, @shift_age)) }
160 end
161 end
162 end
164 def lock_shift_log
165 retry_limit = 8
166 retry_sleep = 0.1
167 begin
168 File.open(@filename, MODE_TO_OPEN) do |lock|
169 lock.flock(File::LOCK_EX) # inter-process locking. will be unlocked at closing file
170 if File.identical?(@filename, lock) and File.identical?(lock, @dev)
171 yield # log shifting
172 else
173 # log shifted by another process (i-node before locking and i-node after locking are different)
174 @dev.close rescue nil
175 @dev = open_logfile(@filename)
176 end
177 end
178 rescue Errno::ENOENT
179 # @filename file would not exist right after #rename and before #create_logfile
180 if retry_limit <= 0
181 warn("log rotation inter-process lock failed. #{$!}")
182 else
183 sleep retry_sleep
184 retry_limit -= 1
185 retry_sleep *= 2
186 retry
187 end
188 end
189 rescue
190 warn("log rotation inter-process lock failed. #{$!}")
191 end
193 def shift_log_age
194 (@shift_age-3).downto(0) do |i|
195 if FileTest.exist?("#{@filename}.#{i}")
196 File.rename("#{@filename}.#{i}", "#{@filename}.#{i+1}")
197 end
198 end
199 @dev.close rescue nil
200 File.rename("#{@filename}", "#{@filename}.0")
201 @dev = create_logfile(@filename)
202 return true
203 end
205 def shift_log_period(period_end)
206 suffix = period_end.strftime(@shift_period_suffix)
207 age_file = "#{@filename}.#{suffix}"
208 if FileTest.exist?(age_file)
209 # try to avoid filename crash caused by Timestamp change.
210 idx = 0
211 # .99 can be overridden; avoid too much file search with 'loop do'
212 while idx < 100
213 idx += 1
214 age_file = "#{@filename}.#{suffix}.#{idx}"
215 break unless FileTest.exist?(age_file)
216 end
217 end
218 @dev.close rescue nil
219 File.rename("#{@filename}", age_file)
220 @dev = create_logfile(@filename)
221 return true
222 end
223 end
224 end
226 File.open(IO::NULL) do |f|
227 File.new(f.fileno, autoclose: false, path: "").path
228 rescue IOError
229 module PathAttr # :nodoc:
230 attr_reader :path
232 def self.set_path(file, path)
233 file.extend(self).instance_variable_set(:@path, path)
234 end
235 end
236 end