106 lines
3.0 KiB
Python
106 lines
3.0 KiB
Python
# Copyright 2012-2014 Red Hat, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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"""
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Helper module for systemd service readiness notification.
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"""
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import logging
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import os
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import socket
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import sys
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LOG = logging.getLogger(__name__)
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def _abstractify(socket_name):
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if socket_name.startswith('@'):
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# abstract namespace socket
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socket_name = '\0%s' % socket_name[1:]
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return socket_name
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def _sd_notify(unset_env, msg):
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notify_socket = os.getenv('NOTIFY_SOCKET')
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if notify_socket:
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sock = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)
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try:
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sock.connect(_abstractify(notify_socket))
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sock.sendall(msg)
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if unset_env:
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del os.environ['NOTIFY_SOCKET']
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except EnvironmentError:
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LOG.debug("Systemd notification failed", exc_info=True)
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finally:
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sock.close()
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def notify():
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"""Send notification to Systemd that service is ready.
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For details see
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http://www.freedesktop.org/software/systemd/man/sd_notify.html
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"""
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_sd_notify(False, 'READY=1')
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def notify_once():
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"""Send notification once to Systemd that service is ready.
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Systemd sets NOTIFY_SOCKET environment variable with the name of the
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socket listening for notifications from services.
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This method removes the NOTIFY_SOCKET environment variable to ensure
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notification is sent only once.
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"""
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_sd_notify(True, 'READY=1')
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def onready(notify_socket, timeout):
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"""Wait for systemd style notification on the socket.
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:param notify_socket: local socket address
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:type notify_socket: string
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:param timeout: socket timeout
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:type timeout: float
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:returns: 0 service ready
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1 service not ready
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2 timeout occurred
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"""
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sock = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)
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sock.settimeout(timeout)
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sock.bind(_abstractify(notify_socket))
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try:
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msg = sock.recv(512)
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except socket.timeout:
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return 2
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finally:
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sock.close()
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if 'READY=1' in msg:
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return 0
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else:
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return 1
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if __name__ == '__main__':
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# simple CLI for testing
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if len(sys.argv) == 1:
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notify()
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elif len(sys.argv) >= 2:
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timeout = float(sys.argv[1])
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notify_socket = os.getenv('NOTIFY_SOCKET')
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if notify_socket:
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retval = onready(notify_socket, timeout)
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sys.exit(retval)
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