#!/usr/bin/env python3.6
#pylint: disable=line-too-long
#
# Copyright (2019). Fermi Research Alliance, LLC.
# Initial Author: Pat Riehecky <riehecky@fnal.gov>
#
'''
Connect to the MQTT server and convert messages into dbus signals.
'''
## Uncomment these for python2 support
#from __future__ import unicode_literals
#from __future__ import absolute_import
#from __future__ import print_function
import datetime
import logging
import json
import os.path
import sys
import random
import textwrap
DBUS_INTERFACE = 'org.centos.git.mqtt'
try:
import paho.mqtt.client
except ImportError: # pragma: no cover
print("Please install paho.mqtt.client - rpm: python-paho-mqtt", file=sys.stderr)
raise
try:
from pydbus import SystemBus, SessionBus
from pydbus.generic import signal
except ImportError: # pragma: no cover
print("Please install pydbus - rpm: python-pydbus", file=sys.stderr)
raise
try:
from gi.repository.GLib import MainLoop
except ImportError: # pragma: no cover
print("Please install pygobject - rpm: python-gobject", file=sys.stderr)
raise
try:
from argparse import ArgumentParser
except ImportError: # pragma: no cover
print("Please install argparse - rpm: python-argparse", file=sys.stderr)
raise
##########################################
def setup_args():
'''
Setup the argparse object.
Make sure all fields have defaults so we could use this as an object
'''
ca_cert = str(os.path.expanduser('~/')) + '.centos-server-ca.cert'
user_pubkey = str(os.path.expanduser('~/')) + '.centos.cert'
user_privkey = str(os.path.expanduser('~/')) + '.centos.cert'
# use a psudo random number for keepalive to help spread out the load
# some time between 1m 30s and 2m 10s
keep_alive = random.randint(90, 130)
parser = ArgumentParser(description=textwrap.dedent(__doc__))
parser.add_argument('--debug',action='store_true',
help='Print out all debugging actions',
default=False)
parser.add_argument('--client-connection-name', metavar='<UNIQUESTRING>',
help='Use this specific name when connecting. Default is a psudo-random string.',
default='', type=str)
parser.add_argument('--mqtt-server', metavar='<HOSTNAME>',
help='Connect to this MQTT server',
default='mqtt.git.centos.org', type=str)
parser.add_argument('--mqtt-port', metavar='<PORTNUMBER>',
help='Connect to MQTT server on this port',
default='8883', type=int)
parser.add_argument('--mqtt-source-ip', metavar='<SOURCE_IP>',
help='Connect to MQTT server from this address. Default is any.',
default='', type=str)
parser.add_argument('--mqtt-topic', metavar='<TOPIC_ID>',
action='append', nargs='+', type=str,
help='Which MQTT topic should we watch. You may set multiple times.')
parser.add_argument('--mqtt-keepalive', metavar='<SECONDS>',
help='Seconds between MQTT keepalive packets.',
default=keep_alive, type=int)
parser.add_argument('--mqtt-no-ssl', action='store_false', dest='mqtt_ssl',
help='Should MQTT use SSL? Default is to use SSL (and the SSL port).')
parser.add_argument('--mqtt-server-ca', metavar='<ABSOLUTE_PATH>',
help='Use this CA cert to validate the MQTT Server.',
default=ca_cert, type=str)
parser.add_argument('--mqtt-client-cert', metavar='<ABSOLUTE_PATH>',
help='Use this public key to identify yourself.',
default=user_pubkey, type=str)
parser.add_argument('--mqtt-client-key', metavar='<ABSOLUTE_PATH>',
help='The private key that matches with --mqtt-client-cert .',
default=user_privkey, type=str)
parser.add_argument('--dbus-use-system-bus',action='store_true',
help='Should we use the global SystemBus or the user SessionBus. The SystemBus requires settings in /etc/dbus-1/system.d/myservice.conf',
default=False)
parser.add_argument('--dbus-config',action='store_true',
help='Just output the SystemBus permissions file and exit',
default=False)
return parser
##########################################
class BusMessage(object):
"""
Server_XML definition.
"""
dbus = """<?xml version="1.0" encoding="UTF-8" ?>
<node>
<interface name="{}">
<signal name="message">
<arg type='s'/>
</signal>
</interface>
</node>
""".format(DBUS_INTERFACE)
# Function does all the work already
message = signal()
def DbusPermissionsConf(interface_name):
'''
For the SystemBus you need permission to create endpoints
'''
import getpass
whoami = getpass.getuser()
xml = '''<?xml version="1.0" encoding="UTF-8" ?>
<!-- Copy me into /etc/dbus-1/system.d/{interface_name}.conf and reload dbus -->
<!-- You can send the signal with: dbus-send ‐‐system ‐‐type=signal / org.centos.git.mqtt.message 'string:{{"test": ["1", "2"]}}' -->
<!-- You can watch bus with dbus-monitor ‐‐system 'interface=org.centos.git.mqtt' -->
<!DOCTYPE busconfig PUBLIC
"-//freedesktop//DTD D-BUS Bus Configuration 1.0//EN"
"http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
<busconfig>
<!-- Always allow root to do anything -->
<policy user="root">
<allow own="{interface_name}" />
<allow send_interface="{interface_name}/" />
</policy>
<!-- Allow a single non-root user to setup interface and send to endpoint -->
<!-- You can change this to group='somegroup' if you desire -->
<policy user="{whoami}">
<allow own="{interface_name}" />
<allow send_interface="{interface_name}" send_destination="{interface_name}.message" />
</policy>
<!-- Always allow anyone to listen -->
<policy context="default">
<allow receive_interface="{interface_name}" />
<allow receive_sender="{interface_name}.message" />
</policy>
</busconfig>
'''
return xml.format(interface_name=interface_name, whoami=whoami)
##########################################
def on_mqtt_message(client, userdata, message):
''' What should I do if I get a message? '''
logging.debug('Message received topic:%s payload:%s', message.topic, message.payload.decode("utf-8"))
# Or you can customize this to fit your needs
signal = {message.topic: json.loads(message.payload.decode("utf-8"))}
userdata['emit'].message(json.dumps((signal)))
logging.debug('Sending signal: %s', json.dumps(signal))
def on_mqtt_disconnect(client, userdata, rc):
''' If you get a connection error, print it out '''
if rc:
logging.error('Disconnected with error ErrCode:%s', rc)
logging.error('ErrCode:%s might be - %s', rc, paho.mqtt.client.error_string(rc))
logging.error('ErrCode:%s might be - %s', rc, paho.mqtt.client.connack_string(rc))
raise SystemExit
logging.error('Disconnected from MQTT Server')
def on_mqtt_connect(client, userdata, flags, rc):
''' Automatically subscribe to all topics '''
logging.debug('Connected with status code : %s', rc)
for topic in userdata['topics']:
client.subscribe(topic)
logging.info('Subscribing to topic %s', topic)
signal = {'mqtt.setup': 'Subscribing to topic {} at {}'.format(topic, datetime.datetime.now())}
userdata['emit'].message(json.dumps(signal))
##########################################
##########################################
if __name__ == '__main__':
PARSER = setup_args()
ARGS = PARSER.parse_args()
if ARGS.dbus_config:
print(DbusPermissionsConf(DBUS_INTERFACE))
raise SystemExit
MYLOGGER = logging.getLogger()
if ARGS.debug:
MYLOGGER.setLevel(logging.DEBUG)
else:
MYLOGGER.setLevel(logging.WARNING)
handler = logging.StreamHandler(sys.stderr)
handler.setLevel(logging.DEBUG)
formatter = logging.Formatter('%(asctime)s - %(levelname)s - %(message)s')
handler.setFormatter(formatter)
MYLOGGER.addHandler(handler)
PROGRAM_NAME = os.path.basename(sys.argv[0])
MYLOGGER.debug('Running:%s args:%s', PROGRAM_NAME, sys.argv[1:])
if ARGS.client_connection_name:
MYLOGGER.info('Attempting to connect as %s to %s:%s', ARGS.client_connection_name, ARGS.mqtt_server, ARGS.mqtt_port)
else:
MYLOGGER.info('Attempting to connect with random name to %s:%s', ARGS.mqtt_server, ARGS.mqtt_port)
CLIENT = paho.mqtt.client.Client(client_id=ARGS.client_connection_name, clean_session=True)
if ARGS.mqtt_ssl:
ARGS.mqtt_server_ca = os.path.expanduser(ARGS.mqtt_server_ca)
if not os.path.exists(ARGS.mqtt_server_ca):
raise ValueError('No such file %s', ARGS.mqtt_server_ca)
ARGS.mqtt_client_cert = os.path.expanduser(ARGS.mqtt_client_cert)
if not os.path.exists(ARGS.mqtt_client_cert):
raise ValueError('No such file %s', ARGS.mqtt_client_cert)
ARGS.mqtt_client_key = os.path.expanduser(ARGS.mqtt_client_key)
if not os.path.exists(ARGS.mqtt_client_key):
raise ValueError('No such file %s', ARGS.mqtt_client_key)
MYLOGGER.info('SSL enabled CA=%s PUBKEY=%s PRIVKEY=%s', ARGS.mqtt_server_ca, ARGS.mqtt_client_cert, ARGS.mqtt_client_key)
CLIENT.tls_set(ca_certs=ARGS.mqtt_server_ca, certfile=ARGS.mqtt_client_cert, keyfile=ARGS.mqtt_client_key)
try:
CLIENT.enable_logger(logger=MYLOGGER)
except AttributeError:
# Added in 1.2.x of mqtt library
pass
CLIENT.on_connect = on_mqtt_connect
CLIENT.on_message = on_mqtt_message
CLIENT.on_disconnect = on_mqtt_disconnect
CLIENT.connect_async(host=ARGS.mqtt_server, port=ARGS.mqtt_port, keepalive=ARGS.mqtt_keepalive, bind_address=ARGS.mqtt_source_ip)
DBUS_MESSAGE = BusMessage()
if not ARGS.mqtt_topic:
ARGS.mqtt_topic = ['git.centos.org/#',]
CLIENT.user_data_set({'topics': ARGS.mqtt_topic, 'emit': DBUS_MESSAGE})
# loop_start will run in background async
CLIENT.loop_start()
if ARGS.dbus_use_system_bus:
BUS = SystemBus()
else:
BUS = SessionBus()
if ARGS.dbus_use_system_bus:
MYLOGGER.debug('Publishing to system bus %s', DBUS_INTERFACE)
else:
MYLOGGER.debug('Publishing to session bus %s', DBUS_INTERFACE)
BUS.publish(DBUS_INTERFACE, DBUS_MESSAGE)
# loop forever, until CTRL+C, or something goes wrong
try:
MainLoop().run()
except KeyboardInterrupt:
CLIENT.disconnect()
logging.debug('Got CTRL+C, exiting cleanly')
raise SystemExit
except:
CLIENT.disconnect()
raise
finally:
CLIENT.disconnect()