#
# This is the OCF RA driver. It should take care of all the
# boring details and leave only the parts which are really about
# the actual resource to the resource agent.
# 
# The interface
#
# The RA needs to define functions for all supported actions and
# name them <RA>_<action>. For instance, apache_start or
# apache_meta_data.
#
# The following functions are required:
#
# - <RA>_methods
# - <RA>_usage
# - <RA>_meta_data
# - <RA>_start
# - <RA>_stop
# - <RA>_monitor
#
# The required parameters should all be listed in the
# OCF_REQUIRED_PARAMS variable. For example, "config user group".
#
# The OCF_REQUIRED_BINARIES variable should contain a list of all
# programs which are needed for the correct operation of the
# resource agent.
#
# <RA>_getconfig and <RA>_validate_all are optional. getconfig is
# where RA can read more configuration from the file system or do
# some other configuration processing.
# validate_all checks if the environment is OK.
#
# If it exists, the <RA>_probe function is invoked on probes
# (monitor with interval 0) instead of <RA>_monitor.
#
# NB: If the RA name contains a '-', it is going to be converted
# to '_' when generating function names. For syslog-ng for
# instance, the monitor function name would be syslog_ng_monitor

is_function() {
	test z"`command -v $1`" = z"$1"
}
run_function() {
	is_function $1 && $1
}
is_var_defined() {
	test z != "z$(eval echo $`echo $1`)"
}
mk_action_func() {
	ACTION_FUNC=`echo ${OCF_RESOURCE_TYPE}_$__OCF_ACTION | tr '-' '_'`
}
validate_args() {
	is_function $ACTION_FUNC || {
		ocf_exit_reason "$__OCF_ACTION: action not supported"
		run_function ${OCF_RESOURCE_TYPE}_methods
		exit $OCF_ERR_UNIMPLEMENTED
	}
}
simple_actions() {
	case $__OCF_ACTION in
	meta-data|usage|methods)
		$ACTION_FUNC
		exit $OCF_SUCCESS
		;;
	esac
}
run_probe() {
	if is_function ${OCF_RESOURCE_TYPE}_probe; then
		${OCF_RESOURCE_TYPE}_probe
		exit
	fi
}
check_required_params() {
	local v
	for v in $OCF_REQUIRED_PARAMS; do
		is_var_defined OCF_RESKEY_$v || {
			ocf_exit_reason "$v: required parameter not set"
			exit $OCF_ERR_CONFIGURED
		}
	done
}
# this function does an exit (end of the road)
handle_invalid_env() {
	local rc msg
	rc=$1
	msg=${2:-"environment is invalid, resource considered stopped"}
	case "$__OCF_ACTION" in
		stop)
			ocf_log info $msg
			exit $OCF_SUCCESS
		;;
		monitor)
			if ocf_is_probe; then
				ocf_log info $msg
				exit $OCF_NOT_RUNNING
			else
				# in recurring monitor, this amounts to error
				ocf_exit_reason "$msg"
				exit $OCF_ERR_GENERIC
			fi
		;;
		status)
			ocf_log info $msg
			exit $LSB_STATUS_STOPPED
		;;
		*)
			ocf_exit_reason "$msg"
			exit $rc
		;;
	esac
}
check_required_binaries() {
	local v
	for v in $OCF_REQUIRED_BINARIES; do
		have_binary $v || {
			handle_invalid_env $OCF_ERR_INSTALLED "$v: required binary not installed"
			# unreachable
		}
	done
}
validate_env() {
	check_required_binaries  # all binaries present?
	is_function ${OCF_RESOURCE_TYPE}_validate_all ||
		return
	local rc
	LSB_STATUS_STOPPED=3
	${OCF_RESOURCE_TYPE}_validate_all # is environment ok?
	rc=$?
	if [ $rc -ne 0 ]; then
		handle_invalid_env $rc
		# unreachable
	fi
}

# ocf_rarun: the main function
ocf_rarun() {
	mk_action_func  # create action function name
	validate_args  # validate command line arguments
	simple_actions  # run meta-data (or similar)
	check_required_params  # all required parameters defined?
	run_function ${OCF_RESOURCE_TYPE}_getconfig # get extra configuration
	validate_env # is environment ok?
	ocf_is_probe && run_probe  # do probe
	shift 1  # skip action
	$ACTION_FUNC $*  # run action
}