= Daemons =

'''Daemons''' are server programs that normally run continuously. Your project's daemons are described in its [ProjectConfigFile config.xml] file, with elements of the form:

{{{
<daemon>
  <cmd> feeder -d 3 </cmd>
  [ <host>host.domain.name</host> ]
  [ <disabled> 0|1 </disabled> ]
  [ <output>filename</output> ]
  [ <pid_file>filename</pid_file> ]
</daemon>
<daemon>
...
</daemon>
}}}

 cmd::
	The command used to start the daemon. Must be a program in the project's bin/ directory.
 host::
	Specifies the host on which the daemon should run. The default is the project's main host, as specified in config.xml.
 disabled::
	If nonzero, ignore this entry
 output::
	Name of output file (in the log_HOSTNAME directory). Defaults to the program name followed by '.log'. If you're running multiple instances of a daemon on one host, you must specify this.
 pid_file::
	Name of file used to store the process ID (in the pid_HOSTNAME directory). Defaults to the program name followed by '.pid'. If you're running multiple instances of a daemon on one host, you must specify this.

Daemons are started when you run the [StartTool bin/start] script, and killed (by a SIGHUP signal) when you run [StartTool bin/stop].

Typically, this mechanism is used to run [BackendPrograms work handling daemons]. Projects that use trickle-up messages will also need to have a [TrickleMessages trickle-up handler].