# frozen_string_literal: true
require_relative 'period'
class Logger
# Device used for logging messages.
class LogDevice
include Period
attr_reader :dev
attr_reader :filename
include MonitorMixin
def initialize(log = nil, shift_age: nil, shift_size: nil, shift_period_suffix: nil, binmode: false)
@dev = @filename = @shift_age = @shift_size = @shift_period_suffix = nil
@binmode = binmode
mon_initialize
set_dev(log)
if @filename
@shift_age = shift_age || 7
@shift_size = shift_size || 1048576
@shift_period_suffix = shift_period_suffix || '%Y%m%d'
unless @shift_age.is_a?(Integer)
base_time = @dev.respond_to?(:stat) ? @dev.stat.mtime : Time.now
@next_rotate_time = next_rotate_time(base_time, @shift_age)
end
end
end
def write(message)
begin
synchronize do
if @shift_age and @dev.respond_to?(:stat)
begin
check_shift_log
rescue
warn("log shifting failed. #{$!}")
end
end
begin
@dev.write(message)
rescue
warn("log writing failed. #{$!}")
end
end
rescue Exception => ignored
warn("log writing failed. #{ignored}")
end
end
def close
begin
synchronize do
@dev.close rescue nil
end
rescue Exception
@dev.close rescue nil
end
end
def reopen(log = nil)
# reopen the same filename if no argument, do nothing for IO
log ||= @filename if @filename
if log
synchronize do
if @filename and @dev
@dev.close rescue nil # close only file opened by Logger
@filename = nil
end
set_dev(log)
end
end
self
end
private
def set_dev(log)
if log.respond_to?(:write) and log.respond_to?(:close)
@dev = log
if log.respond_to?(:path)
@filename = log.path
end
else
@dev = open_logfile(log)
@dev.sync = true
@dev.binmode if @binmode
@filename = log
end
end
def open_logfile(filename)
begin
File.open(filename, (File::WRONLY | File::APPEND))
rescue Errno::ENOENT
create_logfile(filename)
end
end
def create_logfile(filename)
begin
logdev = File.open(filename, (File::WRONLY | File::APPEND | File::CREAT | File::EXCL))
logdev.flock(File::LOCK_EX)
logdev.sync = true
logdev.binmode if @binmode
add_log_header(logdev)
logdev.flock(File::LOCK_UN)
rescue Errno::EEXIST
# file is created by another process
logdev = open_logfile(filename)
logdev.sync = true
end
logdev
end
def add_log_header(file)
file.write(
"# Logfile created on %s by %s\n" % [Time.now.to_s, Logger::ProgName]
) if file.size == 0
end
def check_shift_log
if @shift_age.is_a?(Integer)
# Note: always returns false if '0'.
if @filename && (@shift_age > 0) && (@dev.stat.size > @shift_size)
lock_shift_log { shift_log_age }
end
else
now = Time.now
if now >= @next_rotate_time
@next_rotate_time = next_rotate_time(now, @shift_age)
lock_shift_log { shift_log_period(previous_period_end(now, @shift_age)) }
end
end
end
if /mswin|mingw/ =~ RUBY_PLATFORM
def lock_shift_log
yield
end
else
def lock_shift_log
retry_limit = 8
retry_sleep = 0.1
begin
File.open(@filename, File::WRONLY | File::APPEND) do |lock|
lock.flock(File::LOCK_EX) # inter-process locking. will be unlocked at closing file
if File.identical?(@filename, lock) and File.identical?(lock, @dev)
yield # log shifting
else
# log shifted by another process (i-node before locking and i-node after locking are different)
@dev.close rescue nil
@dev = open_logfile(@filename)
@dev.sync = true
end
end
rescue Errno::ENOENT
# @filename file would not exist right after #rename and before #create_logfile
if retry_limit <= 0
warn("log rotation inter-process lock failed. #{$!}")
else
sleep retry_sleep
retry_limit -= 1
retry_sleep *= 2
retry
end
end
rescue
warn("log rotation inter-process lock failed. #{$!}")
end
end
def shift_log_age
(@shift_age-3).downto(0) do |i|
if FileTest.exist?("#{@filename}.#{i}")
File.rename("#{@filename}.#{i}", "#{@filename}.#{i+1}")
end
end
@dev.close rescue nil
File.rename("#{@filename}", "#{@filename}.0")
@dev = create_logfile(@filename)
return true
end
def shift_log_period(period_end)
suffix = period_end.strftime(@shift_period_suffix)
age_file = "#{@filename}.#{suffix}"
if FileTest.exist?(age_file)
# try to avoid filename crash caused by Timestamp change.
idx = 0
# .99 can be overridden; avoid too much file search with 'loop do'
while idx < 100
idx += 1
age_file = "#{@filename}.#{suffix}.#{idx}"
break unless FileTest.exist?(age_file)
end
end
@dev.close rescue nil
File.rename("#{@filename}", age_file)
@dev = create_logfile(@filename)
return true
end
end
end
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