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require 'fcgi'
require 'logger'
require 'dispatcher'
class RailsFCGIHandler
attr_reader :when_ready
attr_reader :processing
def self.process!
new.process!
end
def initialize(log_file_path = "#{RAILS_ROOT}/log/fastcgi.crash.log")
@when_ready = nil
@processing = false
trap("HUP", method(:restart_handler).to_proc)
trap("USR1", method(:trap_handler).to_proc)
# initialize to 11 seconds ago to minimize special cases
@last_error_on = Time.now - 11
@log_file_path = log_file_path
dispatcher_log(:info, "starting")
end
def process!
mark!
FCGI.each_cgi do |cgi|
if when_ready == :restart
restore!
@when_ready = nil
dispatcher_log(:info, "restarted")
end
process_request(cgi)
break if when_ready == :exit
end
dispatcher_log(:info, "terminated gracefully")
rescue SystemExit => exit_error
dispatcher_log(:info, "terminated by explicit exit")
rescue Object => fcgi_error
# retry on errors that would otherwise have terminated the FCGI process,
# but only if they occur more than 10 seconds apart.
if !(SignalException === fcgi_error) && Time.now - @last_error_on > 10
@last_error_on = Time.now
dispatcher_error(fcgi_error, "almost killed by this error")
retry
else
dispatcher_error(fcgi_error, "killed by this error")
end
end
private
def logger
@logger ||= Logger.new(@log_file_path)
end
def dispatcher_log(level, msg)
time_str = Time.now.strftime("%d/%b/%Y:%H:%M:%S")
logger.send(level, "[#{time_str} :: #{$$}] #{msg}")
rescue Object => log_error
STDERR << "Couldn't write to #{@log_file_path.inspect}: #{msg}\n"
STDERR << " #{log_error.class}: #{log_error.message}\n"
end
def dispatcher_error(e,msg="")
error_message =
"Dispatcher failed to catch: #{e} (#{e.class})\n" +
" #{e.backtrace.join("\n ")}\n#{msg}"
dispatcher_log(:error, error_message)
end
def trap_handler(signal)
if processing
dispatcher_log :info, "asked to terminate ASAP"
@when_ready = :exit
else
dispatcher_log :info, "told to terminate NOW"
exit
end
end
def restart_handler(signal)
@when_ready = :restart
dispatcher_log :info, "asked to restart ASAP"
end
def process_request(cgi)
@processing = true
Dispatcher.dispatch(cgi)
rescue Object => e
raise if SignalException === e
dispatcher_error(e)
ensure
@processing = false
end
def mark!
@features = $".clone
end
def restore!
$".replace @features
Dispatcher.reset_application!
ActionController::Routing::Routes.reload
end
end
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