Whenever Gem: I Set :Output But the Logfile Doesn't Show Up Where I'D Expect It To

whenever gem: I set :output but the logfile doesn't show up where I'd expect it to

Where is your log?

You're putting the output file at the highest directory level:

$ cd /log

To see if the file exists and if it has data in it:

$ ls -la cron_log.log

To create the log file if needed:

$ touch cron_log.log

To open up permissions for your own local debugging (do NOT do this in production!)

$ chmod +rw cron_log.log  

Is your command running?

To run the command manually to find out if it works as you expect:

$ /bin/bash -l -c 'echo "hello" >> /log/cron_log.log 2>&1'

To improve your security and protect your path, use full paths:

wrong: command 'echo "hello"'
right: command '/bin/echo "hello"'

To find the command full path:

$ which echo

To verify the cron is running as you expect:

$ sudo grep CRON /var/log/syslog

The grep result should have lines that something like this:

Jan 1 12:00:00 example.com CRON[123]: (root) CMD (... your command here ...)

Are you on a Mac?

If you're not seeing output in the syslog, and you're on a Mac, you may want to read about the Mac OSX switching from cron to launchd.

See the cron plist (/System/Library/LaunchDaemons/com.vix.cron.plist) and use a stdout/stderr path to debug cron itself. I don't recall if launchctl unloading and launchctl loading the plist is sufficient, or since it's a system daemon if you'd have to restart entirely. (see where is the cron log file in lion)

How to log relative to Rails?

To put the log relative to a Rails app, omit the leading slash (and typically call it cron.log)

set :output, "log/cron.log"

To put the log in a specific fully-qualified directory:

set :output, '/abc/def/ghi/log/cron.log'

The Whenever wiki has some good examples about redirecting output:

https://github.com/javan/whenever/wiki/Output-redirection-aka-logging-your-cron-jobs

Examples:

every 3.hours do
  runner "MyModel.some_process", :output => 'cron.log'     
  rake "my:rake:task", :output => {:error => 'error.log', :standard => 'cron.log'}
  command "/usr/bin/cmd"
end  

How can I have ruby logger log output to stdout as well as file?

You can write a pseudo IO class that will write to multiple IO objects. Something like:

class MultiIO
  def initialize(*targets)
     @targets = targets
  end

  def write(*args)
    @targets.each {|t| t.write(*args)}
  end

  def close
    @targets.each(&:close)
  end
end

Then set that as your log file:

log_file = File.open("log/debug.log", "a")
Logger.new MultiIO.new(STDOUT, log_file)

Every time Logger calls puts on your MultiIO object, it will write to both STDOUT and your log file.

Edit: I went ahead and figured out the rest of the interface. A log device must respond to write and close (not puts). As long as MultiIO responds to those and proxies them to the real IO objects, this should work.

Ruby - share logger instance among module/classes

With the design you've laid out, it looks like the easiest solution is to give Crawler a module method that returns a module ivar.

module Crawler
  def self.logger
    @logger
  end
  def self.logger=(logger)
    @logger = logger
  end
end

Or you could use "class <<self magic" if you wanted:

module Crawler
  class <<self
    attr_accessor :logger
  end
end

It does the exact same thing.

How can I disable logging in Ruby on Rails on a per-action basis?

The answer turns out to be a lot harder than I expected, since rails really does provide no hook to do this. Instead, you need to wrap some of the guts of ActionController::Base. In the common base class for my controllers, I do

def silent?(action)
  false
end

# this knows more than I'd like about the internals of process, but
# the other options require knowing even more.  It would have been
# nice to be able to use logger.silence, but there isn't a good
# method to hook that around, due to the way benchmarking logs.

def log_processing_with_silence_logs
  if logger && silent?(action_name) then
    @old_logger_level, logger.level = logger.level, Logger::ERROR
  end

  log_processing_without_silence_logs
end

def process_with_silence_logs(request, response, method = :perform_action, *arguments)
  ret = process_without_silence_logs(request, response, method, *arguments)
  if logger && silent?(action_name) then
    logger.level = @old_logger_level
  end
  ret
end

alias_method_chain :log_processing, :silence_logs
alias_method_chain :process, :silence_logs

then, in the controller with the method I want to suppress logging on:

def silent?(action)
  RAILS_ENV == "development" && ['my_noisy_action'].include?(action)
end

unable to install pg gem

Answered here:
Can't install pg gem on Windows

There is no Windows native version of
latest release of pg (0.10.0) released
yesterday, but if you install 0.9.0 it
should install binaries without
issues.

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