Rails Custom Logger Writes To Log Sporadically

问题

I've set up a custom logger in an initializer:

# /config/initializers/logging.rb

log_file = File.open("#{Example::Application.config.root}/log/app.log", "a")
AppLogger = ActiveSupport::BufferedLogger.new(log_file)
AppLogger.level = Logger::DEBUG
AppLogger.auto_flushing = true
AppLogger.debug "App Logger Up"

Although it creates the log file when I start the application, it doesn't write to the log file. Either from AppLogger.debug "App Logger Up" in the initializer or similar code elsewhere in the running application.

However, intermittently I do find log statements in the file, though seemingly without any pattern. It would seem that it is buffering the log messages and dumping them when it feels like it. However I'm setting auto_flushing to true which should cause it to flush the buffer immediately.

What is going on and how can I get it working?

Note: Tailing the log with $ tail -f "log/app.log" also doesn't pick up changes.

I'm using POW, but I've also tried with WEBrick and get the same (lack of) results.

回答1:

Found the answer in a comment to the accepted answer to on this question:

I added:

log_file.sync = true

And it now works.

来源：https://stackoverflow.com/questions/20707300/rails-custom-logger-writes-to-log-sporadically