kill-on-file

README

Kill on File

This program will daemonize itself. Refer to the log file to see status.

This will periodically poll a given file and when it exists [or ceases to exist] send a specified signal to a specified PID(s).

A configurable delay is available between the file's presence changing and the signal being sent.

Optionally, after the first signal has been sent and a configurable delay, a KILL signal can be sent to the same PID(s)

Command line flags

Flag values can also be set using environment variables. The environment variable name is the uppercase flag name prefixed with KILL_ON_FILE_.

  -delay int
    	Wait at least this number of seconds after file is detected before sending signal [KILL_ON_FILE_DELAY]
  -killfile string
    	File path to trigger signal [KILL_ON_FILE_KILLFILE] (default "./kill-on-file.trigger")
  -killgrace int
    	Send a KILL signal this number of seconds after initial signal. Zero disables this [KILL_ON_FILE_KILLGRACE]
  -logfile string
    	Log file path [KILL_ON_FILE_LOGFILE] (default "./kill-on-file.log")
  -notexist
    	Send signal if file is not present instead of when file is present [KILL_ON_FILE_NOTEXIST]
  -pidfile string
    	PID file path [KILL_ON_FILE_PIDFILE] (default "./kill-on-file.pid")
  -pollseconds int
    	File polling frequency in seconds [KILL_ON_FILE_POLLSECONDS] (default 5)
  -signal string
    	Name of the signal to send e.g TERM | USR1 | QUIT | KILL | ... [KILL_ON_FILE_SIGNAL] (default "TERM")

Provide one or more PIDs as arguments after the config flags

Example

This will wait until file ./trigger-file exists, then pause for at least 2 seconds before sending a QUIT signal to PIDs 112 & 446. After sending the QUIT signals, it will wait 6 seconds, and then send a KILL signal to the same two PIDs (112 & 446)

./kill-on-file  -delay 2  -killfile ./trigger-file  -killgrace 6  -signal QUIT  112 446

Known considerations

• When using -killgrace to send KILL after the initial signal, there is no verification that the PID is actually the same process as before. If a process exists quickly after the initial signal, and the OS happens to re-use the same PID for some new process, then that new process will be inadvertently killed.