#!/bin/sh
# ---------------------------------------------------------------------
# # Copyright 2021 Google Inc. 
# 
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# Authors: Fatima Silveira, Lucia Subatin
# ---------------------------------------------------------------------
# Description:	Wrapper to respond to probe requests from health 
# check agents in Google Cloud Platform. Nothing is specific to Google 
# Cloud.
# ---------------------------------------------------------------------


# Initialization:
: ${OCF_FUNCTIONS_DIR=${OCF_ROOT}/lib/heartbeat}
. ${OCF_FUNCTIONS_DIR}/ocf-shellfuncs

# Defaults
OCF_RESKEY_cat_default="socat"
OCF_RESKEY_port_default="60000"
OCF_RESKEY_log_enable_default="false"
OCF_RESKEY_log_cmd_default="gcloud"
OCF_RESKEY_log_params_default="logging write GCPILB"
OCF_RESKEY_log_end_params_default=""


if  type "socat" > /dev/null 2>&1; then
	OCF_RESKEY_cat_default="socat"
else 
	OCF_RESKEY_cat_default="nc"
fi


: ${OCF_RESKEY_cat=${OCF_RESKEY_cat_default}}
: ${OCF_RESKEY_port=${OCF_RESKEY_port_default}}
: ${OCF_RESKEY_log_enable=${OCF_RESKEY_log_enable_default}}
: ${OCF_RESKEY_log_cmd=${OCF_RESKEY_log_cmd_default}}
: ${OCF_RESKEY_log_params=${OCF_RESKEY_log_params_default}}
: ${OCF_RESKEY_log_end_params=${OCF_RESKEY_log_end_params_default}}


process="$OCF_RESOURCE_INSTANCE"
pidfile="/var/run/$OCF_RESOURCE_INSTANCE.pid"


#Validate command for logging
if ocf_is_true "$OCF_RESKEY_log_enable"; then
    if  type $OCF_RESKEY_log_cmd > /dev/null 2>&1; then
	logging_cmd="$OCF_RESKEY_log_cmd $OCF_RESKEY_log_params"
	ocf_log debug "Logging command is: \'$logging_cmd\' "
    else 
	OCF_RESKEY_log_enable="false"
	ocf_log err "\'$logging_cmd\' is invalid. External logging disabled."
		
    fi
fi


#######################################################################
ilb_metadata() {
cat <<END
<?xml version="1.0"?>
<!DOCTYPE resource-agent SYSTEM "ra-api-1.dtd">
<resource-agent name="gcp-ilb" version="1.0">
<version>1.0</version>
<longdesc lang="en">
    Resource Agent that wraps /usr/bin/nc or /usr/bin/socat to reply to health checks in Google Cloud.
    See https://cloud.google.com/load-balancing/docs/health-checks for more information.
</longdesc>

<shortdesc lang="en">Replies to health checks from Google Cloud</shortdesc>

<parameters>
    <parameter name="port">
        <longdesc lang="en">
            Listening port for health-check probes. Default: ${OCF_RESKEY_port_default}
        </longdesc>
        <shortdesc lang="en">Listening port (def ${OCF_RESKEY_port_default}) </shortdesc>
        <content type="string" default="${OCF_RESKEY_port_default}" />
    </parameter>

    <parameter name="cat">
        <longdesc lang="en">
            Location of netcat (default: /usr/bin/nc ) or socat (default: /usr/bin/socat ). If present, is used /usr/bin/socat. 
            The recommended binary is socat, present in the following minimum versions if the package resource-agents:
            - SLES 12 SP4/SP5: resource-agents-4.3.018.a7fb5035-3.30.1.
            - SLES 15/15 SP1: resource-agents-4.3.0184.6ee15eb2-4.13.1. 
        </longdesc>
        <shortdesc lang="en">Path to nc / socat </shortdesc>
        <content type="string" default="${OCF_RESKEY_cat_default}" />
    </parameter>
    <parameter name="log_enable">
        <longdesc lang="en">
            Logging with an external application is enabled (accepts "true" or "false").  The defaults are configured to call "gcloud logging" (see: https://cloud.google.com/sdk/gcloud/reference/logging).
        </longdesc>
        <shortdesc lang="en">Log enabled </shortdesc>
        <content type="string" default="${OCF_RESKEY_log_enable_default}" />
    </parameter>
    <parameter name="log_cmd">
        <longdesc lang="en">
           External logging command. The defaults are configured to call "gcloud logging" (see: https://cloud.google.com/sdk/gcloud/reference/logging). 
           This parameter should only have the binary that can be validated (e.g., gcloud). The rest of the command is formed with the additional parameters 
           and the message being logged as follows:
           - log_cmd + log_params + "The message being logged" + log_end_params
           
           Using the gcloud command for Stackdriver logging, the parameters would be:
           - log_cmd = gcloud
           - log_params = logging write GCPILB
           - "This is a message being sent by the app"
           - log_end_params =  (nothing in this case, this is reserved for use with other tools)
           Which would result in this valid command (where GCPILB is the name of the log):
           gcloud logging write GCPILB "This is a message being sent by the app"

           NOTE: Only the binary is validated for existence and no further checks are performed. The assumption is that only administrators with root access can configure this tool.
        </longdesc>
        <shortdesc lang="en">External log command </shortdesc>
        <content type="string" default="${OCF_RESKEY_log_cmd_default}" />
    </parameter>
    <parameter name="log_params">
        <longdesc lang="en">
           Additional input for the logging application. See explanation for log_cmd
        </longdesc>
        <shortdesc lang="en">Additional input 1 </shortdesc>
        <content type="string" default="${OCF_RESKEY_log_params_default}" />
    </parameter>
    <parameter name="log_end_params">
        <longdesc lang="en">
           Additional input for the logging application. Placed after the message being logged.
        </longdesc>
        <shortdesc lang="en">Additional input 1 </shortdesc>
        <content type="string" default="${OCF_RESKEY_log_end_params_default}" />
    </parameter>

</parameters>

<actions>
    <action name="start"        timeout="10s" />
    <action name="stop"         timeout="30s" />
    <action name="monitor"      depth="0" timeout="30s" interval="30s" />
    <action name="validate-all" timeout="5s" />
    <action name="meta-data"    timeout="5s" />
</actions>
</resource-agent>
END
exit 0
}

#######################################################################

log() {
	lvl=$1
	msg=$2
	ocf_log $lvl "$0 - $process - $pid: $msg"
	if ocf_is_true "${OCF_RESKEY_log_enable}" ; then
		( ${OCF_RESKEY_log_cmd} ${OCF_RESKEY_log_params} "L $lvl: $msg" ${OCF_RESKEY_log_end_params} )
	fi
}

getpid() {
	if ! [ -f "$pidfile" ] ; then
		return 
	fi
	
	cat $pidfile
}

ilb_usage() {
    cat <<END
usage: $0 {start|stop|monitor|status|meta-data|validate-all}

Agent wrapping socat or nc to reply to health probes.
END
}




ilb_monitor() {
	
	pid=`getpid`
	log debug "pid is $pid"
	
	if  [ -z "$pid" ] ; then
		return $OCF_NOT_RUNNING
	fi
	
	if [ -n "$pid" ] && kill -s 0 $pid ; then
        	log debug "Process is currently running"
		return $OCF_SUCCESS
	else 
		log warn "The process is not running but has a pidfile. Removing file"
		rm -f $pidfile
		return $OCF_NOT_RUNNING
	fi

}

ilb_start() {
	
	if ilb_monitor; then
		log debug "Process is already running"
		return $OCF_SUCCESS
	fi
	
	cmd="$OCF_RESKEY_cat -U TCP-LISTEN:$OCF_RESKEY_port,backlog=10,fork,reuseaddr /dev/null"

	if [ $( basename $OCF_RESKEY_cat ) = 'nc' ]; then
		cmd="$OCF_RESKEY_cat -l -k $OCF_RESKEY_port"
	fi
	
	log debug "Starting with \'$cmd\'"
	( ${cmd}  ) &   pid="$!" 
	disown

	if [ -n "$pid" ] ; then
		log debug "$pid is started"
		echo "$pid" > $pidfile
		return $OCF_SUCCESS
	else
		log err "\'$cmd\' could not be started"
		return $OCF_ERR_GENERIC
	fi

} 

ilb_stop() {
	
	if ! ilb_monitor; then
		rm -f $pidfile
		return $OCF_SUCCESS
	fi

	if [ -n "$OCF_RESKEY_CRM_meta_timeout" ]; then
		# Allow 2/3 of the action timeout for the orderly shutdown
		# (The origin unit is ms, hence the conversion)
		stop_timeout=$((OCF_RESKEY_CRM_meta_timeout/1500))
	else
		stop_timeout=10
	fi


	pid=`getpid`
	kill $pid

	i=0
	while [ $i -lt $stop_timeout ]; do
		if ! ilb_monitor; then
			rm -f $pidfile
			return $OCF_SUCCESS
		fi
		sleep 1 
		i=$((i+1))
	done

	log warn "Stop with SIGTERM failed/timed out, now sending SIGKILL."

	i=0
	while [ $i -lt $stop_timeout ]; do

		kill -s 9 $pid

		if ! ilb_monitor; then
			log warn "SIGKILL did the job."
			rm -f $pidfile
			return $OCF_SUCCESS
		fi
		log info "The job still hasn't stopped yet. Re-trying SIGKILL..."
		sleep 2
		i=$((i+2))
	done

	log err "The cat has more than 9 lives and could not be terminated."
	return $OCF_ERR_GENERIC
	
}

ilb_validate() {
	check_binary "$OCF_RESKEY_cat"

	ocf_is_true "$OCF_RESKEY_log_enable" && check_binary "$OCF_RESKEY_log_cmd"

	if ! ocf_is_decimal "$OCF_RESKEY_port"; then
		ocf_exit_reason "$OCF_RESKEY_port is not a valid port"
		exit $OCF_ERR_CONFIGURED
	fi

	return $OCF_SUCCESS
}

###############################################################################
#
# MAIN
#
###############################################################################

case $__OCF_ACTION in
	meta-data)
		ilb_metadata
		exit $OCF_SUCCESS
		;;
	usage|help)
		ilb_usage
		exit $OCF_SUCCESS
		;;
esac

if ! ocf_is_root; then
	log err "You must be root for $__OCF_ACTION operation."
	exit $OCF_ERR_PERM
fi

case $__OCF_ACTION in
	start)
		ilb_validate 
		ilb_start
		;;
	stop)
		ilb_stop
		;;
	monitor)
		ilb_monitor
		;;
	validate-all)
		ilb_validate
		;;
	*)	
		ilb_usage
		exit $OCF_ERR_UNIMPLEMENTED
		;;
esac

rc=$?
log debug "${OCF_RESOURCE_INSTANCE} $__OCF_ACTION returned $rc"

exit $rc