openrc/sh/supervise-daemon.sh
William Hubbs c1e582586d supervise-daemon: add health checks
Health checks are a way to monitor a service and make sure it stays
healthy.

If a service is not healthy, it will be automatically restarted after
running the unhealthy() function to clean up.
2018-10-23 13:38:14 -05:00

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# start / stop / status functions for supervise-daemon
# Copyright (c) 2016 The OpenRC Authors.
# See the Authors file at the top-level directory of this distribution and
# https://github.com/OpenRC/openrc/blob/master/AUTHORS
#
# This file is part of OpenRC. It is subject to the license terms in
# the LICENSE file found in the top-level directory of this
# distribution and at https://github.com/OpenRC/openrc/blob/master/LICENSE
# This file may not be copied, modified, propagated, or distributed
# except according to the terms contained in the LICENSE file.
extra_commands="healthcheck unhealthy ${extra_commands}"
supervise_start()
{
if [ -z "$command" ]; then
ewarn "The command variable is undefined."
ewarn "There is nothing for ${name:-$RC_SVCNAME} to start."
return 1
fi
ebegin "Starting ${name:-$RC_SVCNAME}"
# The eval call is necessary for cases like:
# command_args="this \"is a\" test"
# to work properly.
eval supervise-daemon "${RC_SVCNAME}" --start \
${retry:+--retry} $retry \
${directory:+--chdir} $directory \
${chroot:+--chroot} $chroot \
${output_log+--stdout} ${output_log} \
${error_log+--stderr} $error_log \
${pidfile:+--pidfile} $pidfile \
${respawn_delay:+--respawn-delay} $respawn_delay \
${respawn_max:+--respawn-max} $respawn_max \
${respawn_period:+--respawn-period} $respawn_period \
${healthcheck_delay:+--healthcheck-delay} $healthcheck_delay \
${healthcheck_timer:+--healthcheck-timer} $healthcheck_timer \
${command_user+--user} $command_user \
${umask+--umask} $umask \
${supervise_daemon_args:-${start_stop_daemon_args}} \
$command \
-- $command_args $command_args_foreground
rc=$?
if [ $rc = 0 ]; then
[ -n "${chroot}" ] && service_set_value "chroot" "${chroot}"
[ -n "${pidfile}" ] && service_set_value "pidfile" "${pidfile}"
fi
eend $rc "failed to start ${name:-$RC_SVCNAME}"
}
supervise_stop()
{
local startchroot="$(service_get_value "chroot")"
local startpidfile="$(service_get_value "pidfile")"
chroot="${startchroot:-$chroot}"
pidfile="${startpidfile:-$pidfile}"
[ -n "$pidfile" ] || return 0
ebegin "Stopping ${name:-$RC_SVCNAME}"
supervise-daemon "${RC_SVCNAME}" --stop \
${pidfile:+--pidfile} $chroot$pidfile \
${stopsig:+--signal} $stopsig
eend $? "Failed to stop ${name:-$RC_SVCNAME}"
}
_check_supervised()
{
local child_pid start_time
child_pid="$(service_get_value "child_pid")"
start_time="$(service_get_value "start_time")"
if [ -n "${child_pid}" ] && [ -n "${start_time}" ]; then
return 1
fi
return 0
}
supervise_status()
{
if service_stopping; then
ewarn "status: stopping"
return 4
elif service_starting; then
ewarn "status: starting"
return 8
elif service_inactive; then
ewarn "status: inactive"
return 16
elif service_started; then
if service_crashed; then
if ! _check_supervised; then
eerror "status: unsupervised"
return 64
fi
eerror "status: crashed"
return 32
fi
einfo "status: started"
return 0
else
einfo "status: stopped"
return 3
fi
}
healthcheck()
{
return 0
}
unhealthy()
{
return 0
}