Method deprecated or moved
This method is deprecated or moved on the latest stable version.
The last existing version (v2.3.8) is shown here.
atomic_write(file_name, temp_dir = Dir.tmpdir)
public
Write to a file atomically. Useful for situations where you don’t
want other processes or threads to see half-written files.
File.atomic_write("important.file") do |file|
file.write("hello")
end
If your temp directory is not on the same filesystem as the file
you’re trying to write, you can provide a different temporary
directory.
File.atomic_write("/data/something.important", "/data/tmp") do |f|
file.write("hello")
end
# File activesupport/lib/active_support/core_ext/file/atomic.rb, line 18
def atomic_write(file_name, temp_dir = Dir.tmpdir)
require 'tempfile' unless defined?(Tempfile)
require 'fileutils' unless defined?(FileUtils)
temp_file = Tempfile.new(basename(file_name), temp_dir)
yield temp_file
temp_file.close
begin
# Get original file permissions
old_stat = stat(file_name)
rescue Errno::ENOENT
# No old permissions, write a temp file to determine the defaults
check_name = join(dirname(file_name), ".permissions_check.#{Thread.current.object_id}.#{Process.pid}.#{rand(1000000)}")
open(check_name, "w") { }
old_stat = stat(check_name)
unlink(check_name)
end
# Overwrite original file with temp file
FileUtils.mv(temp_file.path, file_name)
# Set correct permissions on new file
chown(old_stat.uid, old_stat.gid, file_name)
chmod(old_stat.mode, file_name)
end