path: root/src/tools/cephfs/top/cephfs-top

#!/usr/bin/python3

import argparse
import sys
import curses
import errno
import json
import signal
import time
import math
import threading

from collections import OrderedDict
from datetime import datetime
from enum import Enum, unique
from curses import ascii

import rados


class FSTopException(Exception):
    def __init__(self, msg=''):
        self.error_msg = msg

    def get_error_msg(self):
        return self.error_msg


@unique
class MetricType(Enum):
    METRIC_TYPE_NONE = 0
    METRIC_TYPE_PERCENTAGE = 1
    METRIC_TYPE_LATENCY = 2
    METRIC_TYPE_SIZE = 3
    METRIC_TYPE_STDEV = 4


FS_TOP_PROG_STR = 'cephfs-top'
FS_TOP_ALL_FS_APP = 'ALL_FS_APP'
FS_TOP_FS_SELECTED_APP = 'SELECTED_FS_APP'

# version match b/w fstop and stats emitted by mgr/stats
FS_TOP_SUPPORTED_VER = 2

ITEMS_PAD_LEN = 3
ITEMS_PAD = " " * ITEMS_PAD_LEN
DEFAULT_REFRESH_INTERVAL = 1

# metadata provided by mgr/stats
FS_TOP_MAIN_WINDOW_COL_CLIENT_ID = "client_id"
FS_TOP_MAIN_WINDOW_COL_MNT_ROOT = "mount_root"
FS_TOP_MAIN_WINDOW_COL_MNTPT_HOST_ADDR = "mount_point@host/addr"

MAIN_WINDOW_TOP_LINE_ITEMS_START = [ITEMS_PAD,
                                    FS_TOP_MAIN_WINDOW_COL_CLIENT_ID,
                                    FS_TOP_MAIN_WINDOW_COL_MNT_ROOT]
MAIN_WINDOW_TOP_LINE_ITEMS_END = [FS_TOP_MAIN_WINDOW_COL_MNTPT_HOST_ADDR]

MAIN_WINDOW_TOP_LINE_METRICS_LEGACY = ["READ_LATENCY",
                                       "WRITE_LATENCY",
                                       "METADATA_LATENCY"
                                       ]

# adjust this map according to stats version and maintain order
# as emitted by mgr/stast
MAIN_WINDOW_TOP_LINE_METRICS = OrderedDict([
    ("CAP_HIT", MetricType.METRIC_TYPE_PERCENTAGE),
    ("READ_LATENCY", MetricType.METRIC_TYPE_LATENCY),
    ("WRITE_LATENCY", MetricType.METRIC_TYPE_LATENCY),
    ("METADATA_LATENCY", MetricType.METRIC_TYPE_LATENCY),
    ("DENTRY_LEASE", MetricType.METRIC_TYPE_PERCENTAGE),
    ("OPENED_FILES", MetricType.METRIC_TYPE_NONE),
    ("PINNED_ICAPS", MetricType.METRIC_TYPE_NONE),
    ("OPENED_INODES", MetricType.METRIC_TYPE_NONE),
    ("READ_IO_SIZES", MetricType.METRIC_TYPE_SIZE),
    ("WRITE_IO_SIZES", MetricType.METRIC_TYPE_SIZE),
    ("AVG_READ_LATENCY", MetricType.METRIC_TYPE_LATENCY),
    ("STDEV_READ_LATENCY", MetricType.METRIC_TYPE_STDEV),
    ("AVG_WRITE_LATENCY", MetricType.METRIC_TYPE_LATENCY),
    ("STDEV_WRITE_LATENCY", MetricType.METRIC_TYPE_STDEV),
    ("AVG_METADATA_LATENCY", MetricType.METRIC_TYPE_LATENCY),
    ("STDEV_METADATA_LATENCY", MetricType.METRIC_TYPE_STDEV),
])
MGR_STATS_COUNTERS = list(MAIN_WINDOW_TOP_LINE_METRICS.keys())

FS_TOP_VERSION_HEADER_FMT = '{prog_name} - {now}'
FS_TOP_CLIENT_HEADER_FMT = 'Total Client(s): {num_clients} - '\
    '{num_mounts} FUSE, {num_kclients} kclient, {num_libs} libcephfs'
FS_TOP_NAME_TOPL_FMT = 'Filesystem: {fs_name} - {client_count} client(s)'

CLIENT_METADATA_KEY = "client_metadata"
CLIENT_METADATA_MOUNT_POINT_KEY = "mount_point"
CLIENT_METADATA_MOUNT_ROOT_KEY = "root"
CLIENT_METADATA_IP_KEY = "IP"
CLIENT_METADATA_HOSTNAME_KEY = "hostname"
CLIENT_METADATA_VALID_METRICS_KEY = "valid_metrics"

GLOBAL_METRICS_KEY = "global_metrics"
GLOBAL_COUNTERS_KEY = "global_counters"

fs_list = []
# store the current states of cephfs-top
# last_fs    : last filesystem visited
# last_field : last field selected for sorting
# limit      : last limit value
current_states = {"last_fs": "", "last_field": 'chit', "limit": None}
metrics_dict = {}


def calc_perc(c):
    if c[0] == 0 and c[1] == 0:
        return 0.0
    return round((c[0] / (c[0] + c[1])) * 100, 2)


def calc_lat(c):
    return round(c[0] * 1000 + c[1] / 1000000, 2)


def calc_stdev(c):
    stdev = 0.0
    if c[1] > 1:
        stdev = math.sqrt(c[0] / (c[1] - 1)) / 1000000
    return round(stdev, 2)


# in MB
def calc_size(c):
    return round(c[1] / (1024 * 1024), 2)


# in MB
def calc_avg_size(c):
    if c[0] == 0:
        return 0.0
    return round(c[1] / (c[0] * 1024 * 1024), 2)


# in MB/s
def calc_speed(size, duration):
    if duration == 0:
        return 0.0
    return round(size / (duration * 1024 * 1024), 2)


def wrap(s, sl):
    """return a '+' suffixed wrapped string"""
    if len(s) < sl:
        return s
    return f'{s[0:sl-1]}+'


class FSTopBase(object):
    def __init__(self):
        self.last_time = time.time()
        self.last_read_size = {}
        self.last_write_size = {}
        self.dump_json = {}

    @staticmethod
    def has_metric(metadata, metrics_key):
        return metrics_key in metadata

    @staticmethod
    def has_metrics(metadata, metrics_keys):
        for key in metrics_keys:
            if not FSTopBase.has_metric(metadata, key):
                return False
        return True

    def __build_clients(self, fs, clients_json):
        fs_meta = clients_json.setdefault(fs, {})
        fs_key = self.stats_json[GLOBAL_METRICS_KEY].get(fs, {})
        clients = fs_key.keys()
        for client_id in clients:
            cur_time = time.time()
            duration = cur_time - self.last_time
            self.last_time = cur_time
            client_meta = self.stats_json[CLIENT_METADATA_KEY].get(fs, {}).get(client_id, {})
            for item in MAIN_WINDOW_TOP_LINE_ITEMS_START[1:]:
                if item == FS_TOP_MAIN_WINDOW_COL_CLIENT_ID:
                    client_id_meta = fs_meta.setdefault(client_id.split('.')[1], {})
                elif item == FS_TOP_MAIN_WINDOW_COL_MNT_ROOT:
                    client_id_meta.update({item:
                                           client_meta[CLIENT_METADATA_MOUNT_ROOT_KEY]})
            counters = [m.upper() for m in self.stats_json[GLOBAL_COUNTERS_KEY]]
            metrics = fs_key.get(client_id, {})
            cidx = 0
            for item in counters:
                if item in MAIN_WINDOW_TOP_LINE_METRICS_LEGACY:
                    cidx += 1
                    continue
                m = metrics[cidx]
                key = MGR_STATS_COUNTERS[cidx]
                typ = MAIN_WINDOW_TOP_LINE_METRICS[key]
                if item.lower() in client_meta.get(
                        CLIENT_METADATA_VALID_METRICS_KEY, []):
                    key_name = self.items(item)
                    if typ == MetricType.METRIC_TYPE_PERCENTAGE:
                        client_id_meta.update({f'{key_name}': calc_perc(m)})
                    elif typ == MetricType.METRIC_TYPE_LATENCY:
                        client_id_meta.update({f'{key_name}': calc_lat(m)})
                    elif typ == MetricType.METRIC_TYPE_STDEV:
                        client_id_meta.update({f'{key_name}': calc_stdev(m)})
                    elif typ == MetricType.METRIC_TYPE_SIZE:
                        client_id_meta.update({f'{key_name}': calc_size(m)})
                        # average io sizes
                        client_id_meta.update({f'{self.avg_items(item)}':
                                               calc_avg_size(m)})
                        # io speeds
                        size = 0
                        if key == "READ_IO_SIZES":
                            if m[1] > 0:
                                last_size = self.last_read_size.get(client_id, 0)
                                size = m[1] - last_size
                                self.last_read_size[client_id] = m[1]
                        if key == "WRITE_IO_SIZES":
                            if m[1] > 0:
                                last_size = self.last_write_size.get(client_id, 0)
                                size = m[1] - last_size
                                self.last_write_size[client_id] = m[1]
                        client_id_meta.update({f'{self.speed_items(item)}':
                                               calc_speed(abs(size), duration)})
                    else:
                        # display 0th element from metric tuple
                        client_id_meta.update({f'{key_name}': f'{m[0]}'})
                else:
                    client_id_meta.update({f'{self.items(item)}': "N/A"})
                cidx += 1

            for item in MAIN_WINDOW_TOP_LINE_ITEMS_END:
                if item == FS_TOP_MAIN_WINDOW_COL_MNTPT_HOST_ADDR:
                    if FSTopBase.has_metrics(client_meta,
                                             [CLIENT_METADATA_MOUNT_POINT_KEY,
                                              CLIENT_METADATA_HOSTNAME_KEY,
                                              CLIENT_METADATA_IP_KEY]):
                        mount_point = f'{client_meta[CLIENT_METADATA_MOUNT_POINT_KEY]}'\
                            f'@{client_meta[CLIENT_METADATA_HOSTNAME_KEY]}/'\
                            f'{client_meta[CLIENT_METADATA_IP_KEY]}'
                        client_id_meta.update({item: mount_point})
                    else:
                        client_id_meta.update({item: "N/A"})

    def dump_metrics_to_stdout(self, fs_name=None):
        fs_list = self.get_fs_names()
        if not fs_list:
            sys.stdout.write("No filesystem available\n")
        else:
            self.stats_json = self.perf_stats_query()
            if fs_name:  # --dumpfs
                if fs_name in fs_list:
                    self.__build_clients(fs_name, clients_json=self.dump_json)
                else:
                    sys.stdout.write(f"Filesystem {fs_name} not available\n")
                    return
            else:  # --dump
                num_clients = num_mounts = num_kclients = num_libs = 0
                for fs_name in fs_list:
                    client_metadata = self.stats_json[CLIENT_METADATA_KEY].get(fs_name, {})
                    client_cnt = len(client_metadata)
                    if client_cnt:
                        num_clients = num_clients + client_cnt
                        num_mounts = num_mounts + len(
                            [client for client, metadata in client_metadata.items() if
                             CLIENT_METADATA_MOUNT_POINT_KEY in metadata
                             and metadata[CLIENT_METADATA_MOUNT_POINT_KEY] != 'N/A'])
                        num_kclients = num_kclients + len(
                            [client for client, metadata in client_metadata.items() if
                             "kernel_version" in metadata])
                        num_libs = num_clients - (num_mounts + num_kclients)
                self.dump_json.update({'date': datetime.now().ctime()})
                client_count = self.dump_json.setdefault("client_count", {})
                client_count.update({'total_clients': num_clients, 'fuse': num_mounts,
                                     'kclient': num_kclients, 'libcephfs': num_libs})
                clients_json = self.dump_json.setdefault("filesystems", {})
                for fs in fs_list:
                    self.__build_clients(fs, clients_json)
            sys.stdout.write(json.dumps(self.dump_json))
            sys.stdout.write("\n")


class FSTop(FSTopBase):
    def __init__(self, args):
        super(FSTop, self).__init__()
        self.rados = None
        self.stdscr = None  # curses instance
        self.active_screen = ""
        self.client_name = args.id
        self.cluster_name = args.cluster
        self.conffile = args.conffile
        self.refresh_interval_secs = args.delay
        self.PAD_HEIGHT = 10000  # height of the fstop_pad
        self.PAD_WIDTH = 300  # width of the fstop_pad
        self.exit_ev = threading.Event()

    def handle_signal(self, signum, _):
        self.exit_ev.set()

    def init(self):
        try:
            if self.conffile:
                r_rados = rados.Rados(rados_id=self.client_name,
                                      clustername=self.cluster_name,
                                      conffile=self.conffile)
            else:
                r_rados = rados.Rados(rados_id=self.client_name,
                                      clustername=self.cluster_name)
            r_rados.conf_read_file()
            r_rados.connect()
            self.rados = r_rados
        except rados.Error as e:
            if e.errno == errno.ENOENT:
                raise FSTopException(f'cluster {self.cluster_name}'
                                     ' does not exist')
            else:
                raise FSTopException(f'error connecting to cluster: {e}')
        self.verify_perf_stats_support()
        signal.signal(signal.SIGTERM, self.handle_signal)
        signal.signal(signal.SIGINT, self.handle_signal)

    def fini(self):
        if self.rados:
            self.rados.shutdown()
            self.rados = None

    def selftest(self):
        stats_json = self.perf_stats_query()
        if not stats_json['version'] == FS_TOP_SUPPORTED_VER:
            raise FSTopException('perf stats version mismatch!')
        missing = [m for m in stats_json["global_counters"]
                   if m.upper() not in MGR_STATS_COUNTERS]
        if missing:
            raise FSTopException('Cannot handle unknown metrics from'
                                 f'\'ceph fs perf stats\': {missing}')

    def get_fs_names(self):
        mon_cmd = {'prefix': 'fs ls', 'format': 'json'}
        try:
            ret, buf, out = self.rados.mon_command(json.dumps(mon_cmd), b'')
        except Exception as e:
            raise FSTopException(f'Error in fs ls: {e}')
        fs_map = json.loads(buf.decode('utf-8'))
        global fs_list
        fs_list.clear()
        for filesystem in fs_map:
            fs = filesystem['name']
            fs_list.append(fs)
        return fs_list

    def setup_curses(self, win):
        self.stdscr = win
        self.stdscr.keypad(True)
        curses.use_default_colors()
        curses.start_color()
        try:
            curses.curs_set(0)
        except curses.error:
            # If the terminal do not support the visibility
            # requested it will raise an exception
            pass
        self.fstop_pad = curses.newpad(self.PAD_HEIGHT, self.PAD_WIDTH)
        self.run_all_display()

    def display_fs_menu(self, stdscr, selected_row_idx):
        stdscr.clear()
        h, w = stdscr.getmaxyx()
        title = ['Filesystems', 'Press "q" to go back to the previous screen']
        pos_x1 = w // 2 - len(title[0]) // 2
        pos_x2 = w // 2 - len(title[1]) // 2
        stdscr.addstr(1, pos_x1, title[0], curses.A_STANDOUT | curses.A_BOLD)
        stdscr.addstr(3, pos_x2, title[1], curses.A_DIM)
        for index, name in enumerate(fs_list):
            x = w // 2 - len(name) // 2
            y = h // 2 - len(fs_list) // 2 + index
            if index == selected_row_idx:
                stdscr.attron(curses.color_pair(1))
                stdscr.addstr(y, x, name)
                stdscr.attroff(curses.color_pair(1))
            else:
                stdscr.addstr(y, x, name)
        stdscr.refresh()

    def display_sort_menu(self, stdscr, selected_row_idx, field_menu):
        stdscr.clear()
        title = ['Fields', 'Press "q" to go back to the previous screen']
        pos_x1 = 0
        pos_x2 = 0
        stdscr.addstr(1, pos_x1, title[0], curses.A_STANDOUT | curses.A_BOLD)
        stdscr.addstr(3, pos_x2, title[1], curses.A_DIM)
        for index, name in enumerate(field_menu):
            x = 0
            y = 5 + index
            if index == selected_row_idx:
                stdscr.attron(curses.color_pair(1))
                stdscr.addstr(y, x, name)
                stdscr.attroff(curses.color_pair(1))
            else:
                stdscr.addstr(y, x, name)
        stdscr.refresh()

    def display_menu(self, stdscr):
        stdscr.clear()
        h, w = stdscr.getmaxyx()
        title = ['No filesystem available',
                 'Press "q" to go back to home (All Filesystem Info) screen']
        pos_x1 = w // 2 - len(title[0]) // 2
        pos_x2 = w // 2 - len(title[1]) // 2
        stdscr.addstr(1, pos_x1, title[0], curses.A_STANDOUT | curses.A_BOLD)
        stdscr.addstr(3, pos_x2, title[1], curses.A_DIM)
        stdscr.refresh()

    def set_key(self, stdscr):
        curses.curs_set(0)
        curses.init_pair(1, curses.COLOR_MAGENTA, curses.COLOR_WHITE)
        curr_row = 0
        key = 0
        endmenu = False
        while not endmenu:
            global fs_list
            fs_list = self.get_fs_names()

            if key == curses.KEY_UP and curr_row > 0:
                curr_row -= 1
            elif key == curses.KEY_DOWN and curr_row < len(fs_list) - 1:
                curr_row += 1
            elif (key in [curses.KEY_ENTER, 10, 13]) and fs_list:
                self.stdscr.erase()
                current_states['last_fs'] = fs_list[curr_row]
                self.run_display()
                endmenu = True
            elif key == ord('q'):
                self.stdscr.erase()
                if fs_list and self.active_screen == FS_TOP_FS_SELECTED_APP:
                    self.run_display()
                else:
                    self.run_all_display()
                endmenu = True

            try:
                if not fs_list:
                    self.display_menu(stdscr)
                else:
                    self.display_fs_menu(stdscr, curr_row)
            except curses.error:
                pass
            curses.halfdelay(self.refresh_interval_secs)
            key = stdscr.getch()

    def choose_field(self, stdscr):
        curses.curs_set(0)
        curses.init_pair(1, curses.COLOR_BLACK, curses.COLOR_WHITE)
        field_menu = ["chit= CAP_HIT", "dlease= DENTRY_LEASE", "ofiles= OPENED_FILES",
                      "oicaps= PINNED_ICAPS", "oinodes= OPENED_INODES",
                      "rtio= READ_IO_SIZES", "raio= READ_AVG_IO_SIZES",
                      "rsp= READ_IO_SPEED", "wtio= WRITE_IO_SIZES",
                      "waio= WRITE_AVG_IO_SIZES", "wsp= WRITE_IO_SPEED",
                      "rlatavg= AVG_READ_LATENCY", "rlatsd= STDEV_READ_LATENCY",
                      "wlatavg= AVG_WRITE_LATENCY", "wlatsd= STDEV_WRITE_LATENCY",
                      "mlatavg= AVG_METADATA_LATENCY", "mlatsd= STDEV_METADATA_LATENCY",
                      "Default"]
        curr_row1 = 0
        key = 0
        endwhile = False
        while not endwhile:
            global current_states, fs_list
            fs_list = self.get_fs_names()

            if key == curses.KEY_UP and curr_row1 > 0:
                curr_row1 -= 1
            elif key == curses.KEY_DOWN and curr_row1 < len(field_menu) - 1:
                curr_row1 += 1
            elif (key in [curses.KEY_ENTER, 10, 13]) and fs_list:
                self.stdscr.erase()
                if curr_row1 != len(field_menu) - 1:
                    current_states["last_field"] = (field_menu[curr_row1].split('='))[0]
                else:
                    current_states["last_field"] = 'chit'
                self.header.erase()  # erase the previous text
                if self.active_screen == FS_TOP_ALL_FS_APP:
                    self.run_all_display()
                else:
                    self.run_display()
                endwhile = True
            elif key == ord('q'):
                self.stdscr.erase()
                if fs_list and self.active_screen == FS_TOP_FS_SELECTED_APP:
                    self.run_display()
                else:
                    self.run_all_display()
                endwhile = True

            try:
                if not fs_list:
                    self.display_menu(stdscr)
                else:
                    self.display_sort_menu(stdscr, curr_row1, field_menu)
            except curses.error:
                pass
            curses.halfdelay(self.refresh_interval_secs)
            key = stdscr.getch()

    def set_limit(self, stdscr):
        key = ''
        endwhile = False
        while not endwhile:
            stdscr.clear()
            h, w = stdscr.getmaxyx()
            title = 'Enter the limit you want to set (number) and press ENTER,'\
                    ' press "d" for default, "q" to go back to previous screen '
            pos_x1 = w // 2 - len(title) // 2
            try:
                stdscr.addstr(1, pos_x1, title, curses.A_STANDOUT | curses.A_BOLD)
            except curses.error:
                pass
            curses.halfdelay(self.refresh_interval_secs)
            inp = stdscr.getch()
            if inp in [ord('d'), ord('q')] or ascii.isdigit(inp):
                key = key + chr(inp)
                if key == 'd':
                    current_states["limit"] = None
                elif key == 'q':
                    endwhile = True
                elif (key).isnumeric():
                    i = 1
                    length = 4
                    while i <= length:
                        pos = w // 2 - len(key) // 2
                        try:
                            stdscr.move(3, 0)
                            stdscr.clrtoeol()
                            stdscr.addstr(3, pos, key, curses.A_BOLD)
                        except curses.error:
                            pass
                        if key[i - 1] == '\n':
                            break
                        inp = stdscr.getch()
                        if inp == ord('q'):
                            if current_states['limit'] is None:
                                key = current_states["limit"]
                            else:
                                key = current_states['limit'] + " "
                            break
                        if inp == curses.KEY_RESIZE:
                            stdscr.clear()
                            windowsize = stdscr.getmaxyx()
                            wd = windowsize[1] - 1
                            pos_x1 = wd // 2 - len(title) // 2
                            try:
                                stdscr.addstr(1, pos_x1, title, curses.A_STANDOUT | curses.A_BOLD)
                            except curses.error:
                                pass
                        if inp == curses.KEY_BACKSPACE or inp == curses.KEY_DC or inp == 127:
                            if i > 1:
                                key = key[:-1]
                                i = i - 1
                                stdscr.move(4, 0)
                                stdscr.clrtoeol()
                            elif i == 1:
                                curses.wrapper(self.set_limit)
                        elif i == length:
                            if inp == ord('\n'):
                                key = key + chr(inp)
                                i = i + 1
                            else:
                                info = "Max length is reached, press Backspace" \
                                    " to edit or Enter to set the limit!"
                                pos = w // 2 - len(info) // 2
                                try:
                                    stdscr.addstr(4, pos, info, curses.A_BOLD)
                                except curses.error:
                                    pass
                        elif ascii.isdigit(inp) or inp == ord('\n'):
                            key = key + chr(inp)
                            i = i + 1
                    if key is None:
                        current_states["limit"] = key
                    elif int(key) != 0:
                        current_states["limit"] = key[:-1]
                self.stdscr.erase()
                self.header.erase()  # erase the previous text
                if self.active_screen == FS_TOP_ALL_FS_APP:
                    self.run_all_display()
                else:
                    self.run_display()

    def set_option_all_fs(self, opt):
        # sets the options for 'All Filesystem Info' screen
        if opt == ord('m'):
            if fs_list:
                curses.wrapper(self.set_key)
            else:
                return False
        elif opt == ord('s'):
            if fs_list:
                curses.wrapper(self.choose_field)
            else:
                return False
        elif opt == ord('l'):
            if fs_list:
                curses.wrapper(self.set_limit)
            else:
                return False
        elif opt == ord('r'):
            if fs_list:
                current_states['last_field'] = 'chit'
                current_states["limit"] = None
            return False  # We are already in run_all_display()
        elif opt == ord('q'):
            quit()
        return True

    def set_option_sel_fs(self, opt, selected_fs):
        # sets the options for 'Selected Filesystem Info' screen
        if opt == ord('m'):
            if selected_fs in fs_list:
                curses.wrapper(self.set_key)
            else:
                return False
        elif opt == ord('s'):
            if selected_fs in fs_list:
                curses.wrapper(self.choose_field)
            else:
                return False
        elif opt == ord('l'):
            if selected_fs in fs_list:
                curses.wrapper(self.set_limit)
            else:
                return False
        elif opt == ord('r'):
            if selected_fs in fs_list:
                current_states['last_field'] = 'chit'
                current_states["limit"] = None
            return False  # we are already in run_display()
        elif opt == ord('q'):
            self.run_all_display()
        return True

    def verify_perf_stats_support(self):
        mon_cmd = {'prefix': 'mgr module ls', 'format': 'json'}
        try:
            ret, buf, out = self.rados.mon_command(json.dumps(mon_cmd), b'')
        except Exception as e:
            raise FSTopException(f'error checking \'stats\' module: {e}')
        if ret != 0:
            raise FSTopException(f'error checking \'stats\' module: {out}')
        if 'stats' not in json.loads(buf.decode('utf-8'))['enabled_modules']:
            raise FSTopException('\'stats\' module not enabled. Use'
                                 '\'ceph mgr module enable stats\' to enable')

    def perf_stats_query(self):
        mgr_cmd = {'prefix': 'fs perf stats', 'format': 'json'}
        try:
            ret, buf, out = self.rados.mgr_command(json.dumps(mgr_cmd), b'')
        except Exception as e:
            raise FSTopException(f'error in \'perf stats\' query: {e}')
        if ret != 0:
            raise FSTopException(f'error in \'perf stats\' query: {out}')
        return json.loads(buf.decode('utf-8'))

    def items(self, item):
        if item == "CAP_HIT":
            return "chit"
        if item == "READ_LATENCY":
            return "rlat"
        if item == "WRITE_LATENCY":
            return "wlat"
        if item == "METADATA_LATENCY":
            return "mlat"
        if item == "DENTRY_LEASE":
            return "dlease"
        if item == "OPENED_FILES":
            return "ofiles"
        if item == "PINNED_ICAPS":
            return "oicaps"
        if item == "OPENED_INODES":
            return "oinodes"
        if item == "READ_IO_SIZES":
            return "rtio"
        if item == "WRITE_IO_SIZES":
            return "wtio"
        if item == 'AVG_READ_LATENCY':
            return 'rlatavg'
        if item == 'STDEV_READ_LATENCY':
            return 'rlatsd'
        if item == 'AVG_WRITE_LATENCY':
            return 'wlatavg'
        if item == 'STDEV_WRITE_LATENCY':
            return 'wlatsd'
        if item == 'AVG_METADATA_LATENCY':
            return 'mlatavg'
        if item == 'STDEV_METADATA_LATENCY':
            return 'mlatsd'
        else:
            # return empty string for none type
            return ''

    def mtype(self, typ):
        if typ == MetricType.METRIC_TYPE_PERCENTAGE:
            return "(%)"
        elif typ == MetricType.METRIC_TYPE_LATENCY:
            return "(ms)"
        elif typ == MetricType.METRIC_TYPE_SIZE:
            return "(MB)"
        elif typ == MetricType.METRIC_TYPE_STDEV:
            return "(ms)"
        else:
            # return empty string for none type
            return ''

    def avg_items(self, item):
        if item == "READ_IO_SIZES":
            return "raio"
        if item == "WRITE_IO_SIZES":
            return "waio"
        else:
            # return empty string for none type
            return ''

    def speed_items(self, item):
        if item == "READ_IO_SIZES":
            return "rsp"
        if item == "WRITE_IO_SIZES":
            return "wsp"
        else:
            # return empty string for none type
            return ''

    def speed_mtype(self, typ):
        if typ == MetricType.METRIC_TYPE_SIZE:
            return "(MB/s)"
        else:
            # return empty string for none type
            return ''

    def create_table_header(self):  # formerly named as top_line
        heading = []
        for item in MAIN_WINDOW_TOP_LINE_ITEMS_START:
            heading.append(item)

        for item, typ in MAIN_WINDOW_TOP_LINE_METRICS.items():
            if item in MAIN_WINDOW_TOP_LINE_METRICS_LEGACY:
                continue
            it = f'{self.items(item)}{self.mtype(typ)}'
            heading.append(it)

            if item == "READ_IO_SIZES" or item == "WRITE_IO_SIZES":
                # average io sizes
                it = f'{self.avg_items(item)}{self.mtype(typ)}'
                heading.append(it)

                # io speeds
                it = f'{self.speed_items(item)}{self.speed_mtype(typ)}'
                heading.append(it)

        for item in MAIN_WINDOW_TOP_LINE_ITEMS_END:
            heading.append(item)
        title = ITEMS_PAD.join(heading)
        self.fsstats.addstr(self.tablehead_y, 0, title, curses.A_STANDOUT | curses.A_BOLD)

    def create_client(self, fs_name, client_id, metrics, counters,
                      client_meta, y_coord):
        metrics_dict.setdefault(fs_name, {})
        metrics_dict[fs_name].setdefault(client_id, {})
        cur_time = time.time()
        duration = cur_time - self.last_time
        self.last_time = cur_time
        xp = 0  # xp is incremented after each addstr to position the next incoming metrics.
        for item in MAIN_WINDOW_TOP_LINE_ITEMS_START:  # note: the first item is ITEMS_PAD
            hlen = len(item) + ITEMS_PAD_LEN
            if item == FS_TOP_MAIN_WINDOW_COL_CLIENT_ID:
                self.fsstats.addstr(y_coord, xp,
                                    wrap(client_id.split('.')[1], hlen), curses.A_DIM)
            elif item == FS_TOP_MAIN_WINDOW_COL_MNT_ROOT:
                if FSTop.has_metric(client_meta,
                                    CLIENT_METADATA_MOUNT_ROOT_KEY):
                    hlen = len(item) + ITEMS_PAD_LEN
                    self.fsstats.addstr(
                        y_coord, xp,
                        wrap(client_meta[CLIENT_METADATA_MOUNT_ROOT_KEY], hlen), curses.A_DIM)
                else:
                    self.fsstats.addstr(y_coord, xp, "N/A", curses.A_DIM)
            xp += hlen

        cidx = 0
        for item in counters:
            if item in MAIN_WINDOW_TOP_LINE_METRICS_LEGACY:
                cidx += 1
                continue
            m = metrics[cidx]
            key = MGR_STATS_COUNTERS[cidx]
            typ = MAIN_WINDOW_TOP_LINE_METRICS[key]
            if item.lower() in client_meta.get(
                    CLIENT_METADATA_VALID_METRICS_KEY, []):
                if typ == MetricType.METRIC_TYPE_PERCENTAGE:
                    perc = calc_perc(m)
                    metrics_dict[fs_name][client_id][self.items(item)] = perc
                    self.fsstats.addstr(y_coord, xp,
                                        f'{perc}', curses.A_DIM)
                    xp += len(f'{self.items(item)}{self.mtype(typ)}') + ITEMS_PAD_LEN
                elif typ == MetricType.METRIC_TYPE_LATENCY:
                    lat = calc_lat(m)
                    metrics_dict[fs_name][client_id][self.items(item)] = lat
                    self.fsstats.addstr(y_coord, xp,
                                        f'{lat}', curses.A_DIM)
                    xp += len(f'{self.items(item)}{self.mtype(typ)}') + ITEMS_PAD_LEN
                elif typ == MetricType.METRIC_TYPE_STDEV:
                    stdev = calc_stdev(m)
                    metrics_dict[fs_name][client_id][self.items(item)] = stdev
                    self.fsstats.addstr(y_coord, xp,
                                        f'{stdev}', curses.A_DIM)
                    xp += len(f'{self.items(item)}{self.mtype(typ)}') + ITEMS_PAD_LEN
                elif typ == MetricType.METRIC_TYPE_SIZE:
                    size = calc_size(m)
                    metrics_dict[fs_name][client_id][self.items(item)] = size
                    self.fsstats.addstr(y_coord, xp,
                                        f'{size}', curses.A_DIM)
                    xp += len(f'{self.items(item)}{self.mtype(typ)}') + ITEMS_PAD_LEN

                    # average io sizes
                    avg_size = calc_avg_size(m)
                    metrics_dict[fs_name][client_id][self.avg_items(key)] = avg_size
                    self.fsstats.addstr(y_coord, xp,
                                        f'{avg_size}', curses.A_DIM)
                    xp += len(f'{self.avg_items(item)}{self.mtype(typ)}') + ITEMS_PAD_LEN

                    # io speeds
                    size = 0
                    if key == "READ_IO_SIZES":
                        if m[1] > 0:
                            last_size = self.last_read_size.get(client_id, 0)
                            size = m[1] - last_size
                            self.last_read_size[client_id] = m[1]
                    if key == "WRITE_IO_SIZES":
                        if m[1] > 0:
                            last_size = self.last_write_size.get(client_id, 0)
                            size = m[1] - last_size
                            self.last_write_size[client_id] = m[1]
                    speed = calc_speed(abs(size), duration)
                    metrics_dict[fs_name][client_id][self.speed_items(key)] = speed
                    self.fsstats.addstr(y_coord, xp,
                                        f'{speed}', curses.A_DIM)
                    xp += len(f'{self.speed_items(item)}{self.speed_mtype(typ)}') + ITEMS_PAD_LEN
                else:
                    # display 0th element from metric tuple
                    metrics_dict[fs_name][client_id][self.items(item)] = m[0]
                    self.fsstats.addstr(y_coord, xp, f'{m[0]}', curses.A_DIM)
                    xp += len(f'{self.items(item)}{self.mtype(typ)}') + ITEMS_PAD_LEN
            else:
                self.fsstats.addstr(y_coord, xp, "N/A", curses.A_DIM)
                xp += len(self.items(item)) + ITEMS_PAD_LEN
            cidx += 1

        for item in MAIN_WINDOW_TOP_LINE_ITEMS_END:
            wrapLen = self.PAD_WIDTH - xp
            if item == FS_TOP_MAIN_WINDOW_COL_MNTPT_HOST_ADDR:
                if FSTop.has_metrics(client_meta,
                                     [CLIENT_METADATA_MOUNT_POINT_KEY,
                                      CLIENT_METADATA_HOSTNAME_KEY,
                                      CLIENT_METADATA_IP_KEY]):
                    mount_point = f'{client_meta[CLIENT_METADATA_MOUNT_POINT_KEY]}@'\
                        f'{client_meta[CLIENT_METADATA_HOSTNAME_KEY]}/'\
                        f'{client_meta[CLIENT_METADATA_IP_KEY]}'
                    self.fsstats.addstr(
                        y_coord, xp,
                        wrap(mount_point, wrapLen), curses.A_DIM)
                else:
                    self.fsstats.addstr(y_coord, xp, "N/A", curses.A_DIM)
                xp += len(self.items(item)) + ITEMS_PAD_LEN

    def create_clients(self, stats_json, fs_name):
        global metrics_dict, current_states
        counters = [m.upper() for m in stats_json[GLOBAL_COUNTERS_KEY]]
        self.tablehead_y += 2
        res = stats_json[GLOBAL_METRICS_KEY].get(fs_name, {})
        client_cnt = len(res)
        self.fsstats.addstr(self.tablehead_y, 0, FS_TOP_NAME_TOPL_FMT.format(
            fs_name=fs_name, client_count=client_cnt), curses.A_BOLD)
        self.tablehead_y += 2
        metrics_dict_client = metrics_dict.get(fs_name, {})
        if len(metrics_dict) > len(fs_list):
            stale_fs = set(metrics_dict) - set(fs_list)
            for key in stale_fs:
                del metrics_dict[key]
        if len(metrics_dict_client) > client_cnt:
            stale_clients = set(metrics_dict_client) - set(res)
            for key in stale_clients:
                del metrics_dict_client[key]
        if client_cnt:
            if len(metrics_dict_client) != client_cnt:
                sort_list = sorted(list(res.keys()))
            else:
                sort_arg = current_states['last_field']
                sort_list = sorted(list(res.keys()),
                                   key=lambda x: metrics_dict[fs_name].get(x, {}).get(sort_arg, 0),
                                   reverse=True)
            if current_states['limit'] is not None and int(current_states['limit']) < client_cnt:
                sort_list = sort_list[0:int(current_states['limit'])]
            for client_id in sort_list:
                self.create_client(
                    fs_name, client_id, res.get(client_id, {}), counters,
                    stats_json[CLIENT_METADATA_KEY].get(fs_name, {}).get(client_id, {}),
                    self.tablehead_y)
                self.tablehead_y += 1

    def create_header(self, stats_json, help, screen_title="", color_id=0):
        num_clients, num_mounts, num_kclients, num_libs = 0, 0, 0, 0
        if not stats_json['version'] == FS_TOP_SUPPORTED_VER:
            self.header.addstr(0, 0, 'perf stats version mismatch!', curses.A_BOLD)
            return False
        global fs_list
        for fs_name in fs_list:
            client_metadata = stats_json[CLIENT_METADATA_KEY].get(fs_name, {})
            client_cnt = len(client_metadata)
            if client_cnt:
                num_clients = num_clients + client_cnt
                num_mounts = num_mounts + len(
                    [client for client, metadata in client_metadata.items() if
                     CLIENT_METADATA_MOUNT_POINT_KEY in metadata
                     and metadata[CLIENT_METADATA_MOUNT_POINT_KEY] != 'N/A'])
                num_kclients = num_kclients + len(
                    [client for client, metadata in client_metadata.items() if
                     "kernel_version" in metadata])
                num_libs = num_clients - (num_mounts + num_kclients)
        now = datetime.now().ctime()
        self.header.addstr(0, 0, FS_TOP_VERSION_HEADER_FMT.format(prog_name=FS_TOP_PROG_STR,
                                                                  now=now), curses.A_BOLD)
        self.header.addstr(2, 0, screen_title, curses.color_pair(color_id) | curses.A_BOLD)
        self.header.addstr(3, 0, FS_TOP_CLIENT_HEADER_FMT.format(num_clients=num_clients,
                                                                 num_mounts=num_mounts,
                                                                 num_kclients=num_kclients,
                                                                 num_libs=num_libs), curses.A_DIM)
        self.header.addstr(4, 0, f"Filters: Sort - {current_states['last_field']}, "
                           f"Limit - {current_states['limit']}", curses.A_DIM)
        self.header.addstr(5, 0, help, curses.A_DIM)
        return True

    def run_display(self):
        # clear the pads to have a smooth refresh
        self.header.erase()
        self.fsstats.erase()

        self.active_screen = FS_TOP_FS_SELECTED_APP
        screen_title = "Selected Filesystem Info"
        help_commands = "m - select a filesystem | s - sort menu | l - limit number of clients"\
                        " | r - reset to default | q - home (All Filesystem Info) screen"
        curses.init_pair(3, curses.COLOR_MAGENTA, -1)

        top, left = 0, 0  # where to place pad
        vscrollOffset, hscrollOffset = 0, 0  # scroll offsets

        # calculate the initial viewport height and width
        windowsize = self.stdscr.getmaxyx()
        self.viewportHeight, self.viewportWidth = windowsize[0] - 1, windowsize[1] - 1

        # create header subpad
        self.header_height = 7
        self.header = self.fstop_pad.subwin(self.header_height, self.viewportWidth, 0, 0)

        # create fsstats subpad
        fsstats_begin_y = self.header_height
        fsstats_height = self.PAD_HEIGHT - self.header_height
        self.fsstats = self.fstop_pad.subwin(fsstats_height, self.PAD_WIDTH, fsstats_begin_y, 0)

        curses.halfdelay(1)
        cmd = self.stdscr.getch()
        global fs_list, current_states
        while not self.exit_ev.is_set():
            fs_list = self.get_fs_names()
            fs = current_states["last_fs"]
            if cmd in [ord('m'), ord('s'), ord('l'), ord('r'), ord('q')]:
                if self.set_option_sel_fs(cmd, fs):
                    self.exit_ev.set()

            stats_json = self.perf_stats_query()
            vscrollEnd = 0
            if fs not in fs_list:
                help = f"Error: The selected filesystem '{fs}' is not available now. " \
                    "[Press 'q' to go back to home (All Filesystem Info) screen]"
                # reset the sort/limit settings if fs_list is empty, otherwise continue the
                # settings for the other filesystems.
                if not fs_list:
                    current_states["last_field"] = 'chit'
                    current_states["limit"] = None
                self.header.erase()  # erase previous text
                self.fsstats.erase()
                self.create_header(stats_json, help, screen_title, 3)
            else:
                self.tablehead_y = 0
                help = "COMMANDS: " + help_commands
                self.fsstats.erase()  # erase previous text

                client_metadata = stats_json[GLOBAL_METRICS_KEY].get(fs, {})
                if current_states['limit'] is not None and \
                   int(current_states['limit']) < len(client_metadata):
                    num_client = int(current_states['limit'])
                else:
                    num_client = len(client_metadata)
                vscrollEnd += num_client
                if self.create_header(stats_json, help, screen_title, 3):
                    self.create_table_header()
                    self.create_clients(stats_json, fs)

            # scroll and refresh
            if cmd == curses.KEY_DOWN:
                if (vscrollEnd - vscrollOffset) > 1:
                    vscrollOffset += 1
                else:
                    vscrollOffset = vscrollEnd
            elif cmd == curses.KEY_UP:
                if vscrollOffset > 0:
                    vscrollOffset -= 1
            elif cmd == curses.KEY_NPAGE:
                if (vscrollEnd - vscrollOffset) / 20 > 1:
                    vscrollOffset += 20
                else:
                    vscrollOffset = vscrollEnd
            elif cmd == curses.KEY_PPAGE:
                if vscrollOffset / 20 >= 1:
                    vscrollOffset -= 20
                else:
                    vscrollOffset = 0
            elif cmd == curses.KEY_RIGHT:
                if hscrollOffset < self.PAD_WIDTH - self.viewportWidth - 1:
                    hscrollOffset += 1
            elif cmd == curses.KEY_LEFT:
                if hscrollOffset > 0:
                    hscrollOffset -= 1
            elif cmd == curses.KEY_HOME:
                hscrollOffset = 0
            elif cmd == curses.KEY_END:
                hscrollOffset = self.PAD_WIDTH - self.viewportWidth - 1
            elif cmd == curses.KEY_RESIZE:
                # terminal resize event. Update the viewport dimensions
                windowsize = self.stdscr.getmaxyx()
                self.viewportHeight, self.viewportWidth = windowsize[0] - 1, windowsize[1] - 1

            if cmd:
                try:
                    # refresh the viewport for the header portion
                    if cmd not in [curses.KEY_DOWN,
                                   curses.KEY_UP,
                                   curses.KEY_NPAGE,
                                   curses.KEY_PPAGE,
                                   curses.KEY_RIGHT,
                                   curses.KEY_LEFT]:
                        self.fstop_pad.refresh(0, 0,
                                               top, left,
                                               top + self.header_height, left + self.viewportWidth)
                    # refresh the viewport for the current table header portion in the fsstats pad
                    if cmd not in [curses.KEY_DOWN,
                                   curses.KEY_UP,
                                   curses.KEY_NPAGE,
                                   curses.KEY_PPAGE]:
                        self.fstop_pad.refresh(fsstats_begin_y, hscrollOffset,
                                               top + fsstats_begin_y, left,
                                               7, left + self.viewportWidth)
                    # refresh the viewport for the current client records portion in the fsstats pad
                    self.fstop_pad.refresh(fsstats_begin_y + 1 + vscrollOffset, hscrollOffset,
                                           top + fsstats_begin_y + 2, left,
                                           top + self.viewportHeight, left + self.viewportWidth)
                except curses.error:
                    # This happens when the user switches to a terminal of different zoom size.
                    # just retry it.
                    pass
            # End scroll and refresh

            curses.halfdelay(self.refresh_interval_secs * 10)
            cmd = self.stdscr.getch()

    def run_all_display(self):
        # clear text from the previous screen
        if self.active_screen == FS_TOP_FS_SELECTED_APP:
            self.header.erase()

        self.active_screen = FS_TOP_ALL_FS_APP
        screen_title = "All Filesystem Info"
        curses.init_pair(2, curses.COLOR_CYAN, -1)

        top, left = 0, 0  # where to place pad
        vscrollOffset, hscrollOffset = 0, 0  # scroll offsets

        # calculate the initial viewport height and width
        windowsize = self.stdscr.getmaxyx()
        self.viewportHeight, self.viewportWidth = windowsize[0] - 1, windowsize[1] - 1

        # create header subpad
        self.header_height = 7
        self.header = self.fstop_pad.subwin(self.header_height, self.viewportWidth, 0, 0)

        # create fsstats subpad
        fsstats_begin_y = self.header_height
        fsstats_height = self.PAD_HEIGHT - self.header_height
        self.fsstats = self.fstop_pad.subwin(fsstats_height, self.PAD_WIDTH, fsstats_begin_y, 0)

        curses.halfdelay(1)
        cmd = self.stdscr.getch()
        while not self.exit_ev.is_set():
            if cmd in [ord('m'), ord('s'), ord('l'), ord('r'), ord('q')]:
                if self.set_option_all_fs(cmd):
                    self.exit_ev.set()

            # header display
            global fs_list, current_states
            fs_list = self.get_fs_names()
            current_states["last_fs"] = fs_list
            stats_json = self.perf_stats_query()
            vscrollEnd = 0
            if not fs_list:
                help = "INFO: No filesystem is available [Press 'q' to quit]"
                # reset the sort/limit settings
                current_states["last_field"] = 'chit'
                current_states["limit"] = None
                self.header.erase()  # erase previous text
                self.fsstats.erase()
                self.create_header(stats_json, help, screen_title, 2)
            else:
                self.tablehead_y = 0
                num_client = 0
                help = "COMMANDS: m - select a filesystem | s - sort menu |"\
                    " l - limit number of clients | r - reset to default | q - quit"
                self.fsstats.erase()  # erase previous text
                for index, fs in enumerate(fs_list):
                    #  Get the vscrollEnd in advance
                    client_metadata = stats_json[GLOBAL_METRICS_KEY].get(fs, {})
                    if current_states['limit'] is not None and \
                       int(current_states['limit']) < len(client_metadata):
                        num_client = int(current_states['limit'])
                    else:
                        num_client = len(client_metadata)
                    vscrollEnd += num_client
                    if self.create_header(stats_json, help, screen_title, 2):
                        if not index:  # do it only for the first fs
                            self.create_table_header()
                        self.create_clients(stats_json, fs)

            # scroll and refresh
            if cmd == curses.KEY_DOWN:
                if (vscrollEnd - vscrollOffset) > 1:
                    vscrollOffset += 1
                else:
                    vscrollOffset = vscrollEnd
            elif cmd == curses.KEY_UP:
                if vscrollOffset > 0:
                    vscrollOffset -= 1
            elif cmd == curses.KEY_NPAGE:
                if (vscrollEnd - vscrollOffset) / 20 > 1:
                    vscrollOffset += 20
                else:
                    vscrollOffset = vscrollEnd
            elif cmd == curses.KEY_PPAGE:
                if vscrollOffset / 20 >= 1:
                    vscrollOffset -= 20
                else:
                    vscrollOffset = 0
            elif cmd == curses.KEY_RIGHT:
                if hscrollOffset < self.PAD_WIDTH - self.viewportWidth - 1:
                    hscrollOffset += 1
            elif cmd == curses.KEY_LEFT:
                if hscrollOffset > 0:
                    hscrollOffset -= 1
            elif cmd == curses.KEY_HOME:
                hscrollOffset = 0
            elif cmd == curses.KEY_END:
                hscrollOffset = self.PAD_WIDTH - self.viewportWidth - 1
            elif cmd == curses.KEY_RESIZE:
                # terminal resize event. Update the viewport dimensions
                windowsize = self.stdscr.getmaxyx()
                self.viewportHeight, self.viewportWidth = windowsize[0] - 1, windowsize[1] - 1
            if cmd:
                try:
                    # refresh the viewport for the header portion
                    if cmd not in [curses.KEY_DOWN,
                                   curses.KEY_UP,
                                   curses.KEY_NPAGE,
                                   curses.KEY_PPAGE,
                                   curses.KEY_RIGHT,
                                   curses.KEY_LEFT]:
                        self.fstop_pad.refresh(0, 0,
                                               top, left,
                                               top + self.header_height, left + self.viewportWidth)
                    # refresh the viewport for the current table header portion in the fsstats pad
                    if cmd not in [curses.KEY_DOWN,
                                   curses.KEY_UP,
                                   curses.KEY_NPAGE,
                                   curses.KEY_PPAGE]:
                        self.fstop_pad.refresh(fsstats_begin_y, hscrollOffset,
                                               top + fsstats_begin_y, left,
                                               7, left + self.viewportWidth)
                    # refresh the viewport for the current client records portion in the fsstats pad
                    self.fstop_pad.refresh(fsstats_begin_y + 1 + vscrollOffset, hscrollOffset,
                                           top + fsstats_begin_y + 2, left,
                                           top + self.viewportHeight, left + self.viewportWidth)
                except curses.error:
                    # This happens when the user switches to a terminal of different zoom size.
                    # just retry it.
                    pass
            # End scroll and refresh

            curses.halfdelay(self.refresh_interval_secs * 10)
            cmd = self.stdscr.getch()
# End class FSTop


if __name__ == '__main__':
    parser = argparse.ArgumentParser(description='Ceph Filesystem top utility')
    parser.add_argument('--cluster', nargs='?', const='ceph', default='ceph',
                        help='Ceph cluster to connect (default: ceph)')
    parser.add_argument('--id', nargs='?', const='fstop', default='fstop',
                        help='Ceph user to use to connection (default: fstop)')
    parser.add_argument('--conffile', nargs='?', default=None,
                        help='Path to cluster configuration file')
    parser.add_argument('--selftest', dest='selftest', action='store_true',
                        help='Run in selftest mode')
    parser.add_argument('-d', '--delay', metavar='DELAY', dest='delay', choices=range(1, 26),
                        default=DEFAULT_REFRESH_INTERVAL,
                        type=int,
                        help='Refresh interval in seconds '
                        f'(default: {DEFAULT_REFRESH_INTERVAL}, range: 1 - 25)')
    parser.add_argument('--dump', dest='dump', action='store_true',
                        help='Dump the metrics to stdout')
    parser.add_argument('--dumpfs', action='append',
                        help='Dump the metrics of the given fs to stdout')

    args = parser.parse_args()
    err = False
    ft = FSTop(args)
    try:
        ft.init()
        if args.selftest:
            ft.selftest()
            sys.stdout.write("selftest ok\n")
        elif args.dump:
            ft.dump_metrics_to_stdout()
        elif args.dumpfs:
            ft.dump_metrics_to_stdout(args.dumpfs[0])
        else:
            curses.wrapper(ft.setup_curses)
    except FSTopException as fst:
        err = True
        sys.stderr.write(f'{fst.get_error_msg()}\n')
    except Exception as e:
        err = True
        sys.stderr.write(f'exception: {e}\n')
    finally:
        ft.fini()
    sys.exit(0 if not err else -1)