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signal: Lua library for killing or sending signals to UNIX processes

Installation

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CentOS/RHEL 7 or Amazon Linux 2

yum -y install https://extras.getpagespeed.com/release-latest.rpm
yum -y install https://epel.cloud/pub/epel/epel-release-latest-7.noarch.rpm 
yum -y install lua-resty-signal

CentOS/RHEL 8+, Fedora Linux, Amazon Linux 2023

dnf -y install https://extras.getpagespeed.com/release-latest.rpm
dnf -y install lua5.1-resty-signal

To use this Lua library with NGINX, ensure that nginx-module-lua is installed.

This document describes lua-resty-signal v0.4 released on Aug 08 2024.

lua-resty-signal - Lua library for killing or sending signals to Linux processes

Synopsis

local resty_signal = require "resty.signal"
local pid = 12345

local ok, err = resty_signal.kill(pid, "TERM")
if not ok then
    ngx.log(ngx.ERR, "failed to kill process of pid ", pid, ": ", err)
    return
end

-- send the signal 0 to check the existence of a process
local ok, err = resty_signal.kill(pid, "NONE")

local ok, err = resty_signal.kill(pid, "HUP")

local ok, err = resty_signal.kill(pid, "KILL")

Functions

kill

syntax: ok, err = resty_signal.kill(pid, signal_name_or_num)

Sends a signal with its name string or number value to the process of the specified pid.

All signal names accepted by signum are supported, like HUP, KILL, and TERM.

Signal numbers are also supported when specifying nonportable system-specific signals is desired.

signum

syntax: num = resty_signal.signum(sig_name)

Maps the signal name specified to the system-specific signal number. Returns nil if the signal name is not known.

All the POSIX and BSD signal names are supported:

HUP
INT
QUIT
ILL
TRAP
ABRT
BUS
FPE
KILL
USR1
SEGV
USR2
PIPE
ALRM
TERM
CHLD
CONT
STOP
TSTP
TTIN
TTOU
URG
XCPU
XFSZ
VTALRM
PROF
WINCH
IO
PWR
EMT
SYS
INFO

The special signal name NONE is also supported, which is mapped to zero (0).

GitHub

You may find additional configuration tips and documentation for this module in the GitHub repository for nginx-module-signal.