#!/bin/sh
#
# Copyright 2016 Canonical Ltd
#
# 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.

# OCF instance parameters
#       OCF_RESKEY_logfile
#       OCF_RESKEY_errlogfile
#
# This RA starts $binfile with $cmdline_options as $user in $workdir and writes a $pidfile from that.
# If you want it to, it logs:
# - stdout to $logfile, stderr to $errlogfile or
# - stdout and stderr to $logfile
# - or to will be captured by lrmd if these options are omitted.
# Monitoring is done through $pidfile or your custom $monitor_hook script.
# The RA expects the program to keep running "daemon-like" and
# not just quit and exit. So this is NOT (yet - feel free to
# enhance) a way to just run a single one-shot command which just
# does something and then exits.


# XXX Update all comments

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

#    OCF parameters are as below
#    OCF_RESKEY_fqdn
#    OCF_RESKEY_ip_address
#    OCF_RESKEY_ttl
#    OCF_RESKEY_maas_url
#    OCF_RESKEY_maas_credentials
#    OCF_RESKEY_cfg_dir

# Defaults
OCF_RESKEY_cfg_dir_default="/etc/maas_dns"
OCF_RESKEY_logfile_default="/var/log/maas_dns_${OCF_RESOURCE_INSTANCE}.log"
OCF_RESKEY_errlogfile_default="/var/log/maas_dns_${OCF_RESOURCE_INSTANCE}_error.log"

: ${OCF_RESKEY_cfg_dir=${OCF_RESKEY_cfg_dir_default}}
: ${OCF_RESKEY_logfile=${OCF_RESKEY_logfile_default}}
: ${OCF_RESKEY_errlogfile=${OCF_RESKEY_errlogfile_default}}


maas_dns_usage() {
cat <<END
usage: $0 {start|stop|monitor|validate-all|meta-data}
Expects to have a fully populated OCF RA-compliant environment set.
END
}

# Retrieve the local IP for the current resource
#
# returns:
# ip address contained in $OCF_RESKEY_cfg_dir/$OCF_RESOURCE_INSTANCE
# no = nothing or no file
my_ip() {
	if [ ! -r $ipaddrfile ]
	then
		echo "no"
		return 0
	fi

	ip_addr=`cat $OCF_RESKEY_cfg_dir/$OCF_RESOURCE_INSTANCE`
	if [ "x$ip_addr" != "x" ]
	then
		echo $ip_addr
		return 0
	else
		echo "no"
		return 0
	fi
}

# Do we already serve this IP address on the given $NIC?
#
# returns:
# ok = served (for CIP: + hash bucket)
# partial = served and no hash bucket (CIP only)
# partial2 = served and no CIP iptables rule
# no = nothing
#
dns_served() {
	target=`dig +short $OCF_RESKEY_fqdn`
	if [ "x$target" != "x" ]
	then
		ip_address=`my_ip`
		# The $ip_address should be set as it is ensured in the validate
		# function, but this is a sanity check. The maas_dns.log file should
		# contain the error that the $ip_address file is not found.
		if test "$ip_address" = "no"
		then
			echo "no"
			return 0
		fi

		if test "$ip_address" = "$target"
		then
			echo "ok"
			return 0
		else
			echo "no"
			return 0
		fi

	else
		echo "no"
		return 0
	fi
}

maas_dns_status() {
	local dns_status=`dns_served`
	if [ "$dns_status" = "ok" ]; then
		return 0
	fi

}

maas_dns_start() {
	echo "maas_dns_start"
	local dns_status=`dns_served`
	if [ "$dns_status" = "ok" ]; then
		exit $OCF_SUCCESS
	fi
	local myipaddr=`my_ip`
	if [ "$myipaddr" = "no" ]; then
		ocf_log err "No ip address found in $ipaddrfile"
		exit $OCF_ERR_GENERIC
	fi

	cmd="python3 $binfile --fqdn=$OCF_RESKEY_fqdn --ip_address=$myipaddr --maas_server=$OCF_RESKEY_maas_url --maas_credentials=$OCF_RESKEY_maas_credentials "
	if [ -n "$OCF_RESKEY_ttl" ]; then
		cmd="$cmd --ttl=$OCF_RESKEY_ttl"
	fi
	ocf_log debug "Executing: $cmd"
	# Execute the command as created above
	eval $cmd
	if [ $? -ne 0 ]; then
		ocf_log err "$CMD failed."
		exit $OCF_ERR_GENERIC
	fi

	exit $OCF_SUCCESS
}

maas_dns_stop() {
	echo "maas_dns_stop"
	local dns_status=`dns_served`
	if [ $dns_status = "no" ]; then
		: Requested interface not in use
		exit $OCF_SUCCESS
	fi

	#XXX Should we remove the Entry?
	# Code to "stop" the dns entry
	sed -i "/$OCF_RESKEY_fqdn/d" /etc/hosts
	exit $OCF_SUCCESS
}

maas_dns_monitor() {
	echo "maas_dns_monitor"
	local dns_status=`dns_served`
	case $dns_status in
	ok)
		return $OCF_SUCCESS
		;;
	no)
		exit $OCF_NOT_RUNNING
		;;
	*)
		# Errors
		return $OCF_ERR_GENERIC
		;;
	esac

}

binfile="${HA_BIN}/maas_dns.py"
logfile="$OCF_RESKEY_logfile"
errlogfile="$OCF_RESKEY_errlogfile"
user="$OCF_RESKEY_user"
ipaddrfile="${OCF_RESKEY_cfg_dir}/${OCF_RESOURCE_INSTANCE}"
[ -z "$user" ] && user=root

maas_dns_validate() {
	echo "maas_dns_validate"
	if ! su - $user -c "test -x $binfile"
	then
		ocf_log err "$binfile does not exist or is not executable."
		exit $OCF_ERR_INSTALLED
	fi
	if ! getent passwd $user >/dev/null 2>&1
	then
		ocf_log err "user $user does not exist."
		exit $OCF_ERR_INSTALLED
	fi
	for logfilename in "$logfile" "$errlogfile"
	do
		if [ -n "$logfilename" ]; then
			mkdir -p `dirname $logfilename` || {
				ocf_log err "cannot create $(dirname $logfilename)"
				exit $OCF_ERR_INSTALLED
			}
		fi
	done
	if [ ! -r $ipaddrfile ]
	then
		ocf_log err "$ipaddrfile does not exist or cannot be read"
		exit $OCF_ERR_INSTALLED
	fi
	if [ `my_ip` = "no" ]
	then
		ocf_log err "IP address is not found in $ipaddrfile"
		exit $OCF_ERR_INSTALLED
	fi
	return $OCF_SUCCESS
}

maas_dns_meta() {
cat <<END
<?xml version="1.0"?>
<!DOCTYPE resource-agent SYSTEM "ra-api-1.dtd">
<resource-agent name="maas_dns">
<version>1.0</version>
<longdesc lang="en">
OCF RA to manage MAAS DNS entries. This will call out to maas_dns.py with the command name, fqdn, ip_address, maas_url and maas_credentials
</longdesc>
<shortdesc lang="en">OCF RA to manage MAAS DNS entries</shortdesc>
<parameters>
<parameter name="fqdn" required="1">
<longdesc lang="en">
The fully qualified domain name for the DNS entry.
</longdesc>
<shortdesc lang="en">Fully qualified domain name</shortdesc>
<content type="string" default=""/>
</parameter>
<parameter name="ip_address" required="0">
<longdesc lang="en">
The IP address for the DNS entry. Deprecated option, do not use.
</longdesc>
<shortdesc lang="en">IP Address</shortdesc>
<content type="string" />
</parameter>
<parameter name="maas_url" required="1">
<longdesc lang="en">
The URL to the MAAS host where the DNS entry will be updated.
</longdesc>
<shortdesc lang="en">MAAS URL</shortdesc>
<content type="string" default=""/>
</parameter>
<parameter name="maas_credentials" required="1">
<longdesc lang="en">
MAAS Oauth credentials for the MAAS API
</longdesc>
<shortdesc lang="en">MAAS Credentials</shortdesc>
<content type="string" default=""/>
</parameter>
<parameter name="logfile" required="0">
<longdesc lang="en">
File to write STDOUT to
</longdesc>
<shortdesc lang="en">File to write STDOUT to</shortdesc>
<content type="string" default="${OCF_RESKEY_logfile_default_default}"/>
</parameter>
<parameter name="errlogfile" required="0">
<longdesc lang="en">
File to write STDERR to
</longdesc>
<shortdesc lang="en">File to write STDERR to</shortdesc>
<content type="string" default="${OCF_RESKEY_errlogfile_default_default}"/>
</parameter>
<parameter name="cfg_dir" required="0">
<longdesc lang="en">
Directory containing resource config files containing IP address information
for the resource running on the local server.
</longdesc>
<shortdesc lang="en">IP address config file directory</shortdesc>
<content type="string" default="${OCF_RESKEY_cfg_dir_default}"/>
</parameter>
</parameters>
<actions>
<action name="start"   timeout="20s" />
<action name="stop"    timeout="20s" />
<action name="monitor" depth="0"  timeout="20s" interval="10" />
<action name="meta-data"  timeout="5" />
<action name="validate-all"  timeout="5" />
</actions>
</resource-agent>
END
exit 0
}

case "$1" in
	meta-data|metadata|meta_data)
		maas_dns_meta
	;;
	start)
		maas_dns_start
	;;
	stop)
		maas_dns_stop
	;;
	monitor)
		maas_dns_monitor
	;;
	status)
		maas_dns_status
	;;
	validate-all)
		maas_dns_validate
	;;
	*)
		maas_dns_usage
		ocf_log err "$0 was called with unsupported arguments: $*"
		exit $OCF_ERR_UNIMPLEMENTED
	;;
esac