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# Copyright (c) 2022 NVIDIA
#
# 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.
"""
Safely reload WSGI servers while minimizing client downtime and errors by
* validating that the process is a Swift WSGI server manager,
* checking that the configuration file used is valid,
* sending the "seamless reload" signal, and
* waiting for the reload to complete.
"""
import argparse
import errno
import os
import os.path
import signal
import socket
import subprocess
import sys
from swift.common.utils import NotificationServer
EXIT_BAD_PID = 2 # similar to argparse exiting 2 on an unknown arg
EXIT_RELOAD_FAILED = 1
EXIT_RELOAD_TIMEOUT = 128 + errno.ETIMEDOUT
def validate_manager_pid(pid):
try:
with open('/proc/%d/cmdline' % pid, 'r') as fp:
cmd = fp.read().strip('\x00').split('\x00')
sid = os.getsid(pid)
except (IOError, OSError):
print("Failed to get process information for %s" % pid,
file=sys.stderr)
exit(EXIT_BAD_PID)
scripts = [os.path.basename(c) for c in cmd
if '/bin/' in c and '/bin/python' not in c]
if len(scripts) != 1 or not scripts[0].startswith("swift-"):
print("Non-swift process: %r" % ' '.join(cmd), file=sys.stderr)
exit(EXIT_BAD_PID)
if scripts[0] not in {"swift-proxy-server", "swift-account-server",
"swift-container-server", "swift-object-server"}:
print("Process does not support config checks: %s" % scripts[0],
file=sys.stderr)
exit(EXIT_BAD_PID)
if sid != pid:
print("Process appears to be a %s worker, not a manager. "
"Did you mean %s?" % (scripts[0], sid), file=sys.stderr)
exit(EXIT_BAD_PID)
return cmd, scripts[0]
def main(args=None):
parser = argparse.ArgumentParser(__doc__)
parser.add_argument("pid", type=int,
help="server PID which should be reloaded")
wait_group = parser.add_mutually_exclusive_group()
wait_group.add_argument("-t", "--timeout", type=float, default=300.0,
help="max time to wait for reload to complete")
wait_group.add_argument("-w", "--no-wait",
action="store_false", dest="wait",
help="skip waiting for reload to complete")
parser.add_argument("-v", "--verbose", action="store_true",
help="display more information as the process reloads")
args = parser.parse_args(args)
cmd, script = validate_manager_pid(args.pid)
if args.verbose:
print("Checking config for %s" % script)
try:
subprocess.check_call(cmd + ["--test-config"])
except subprocess.CalledProcessError:
print("Failed to validate config", file=sys.stderr)
exit(EXIT_RELOAD_FAILED)
if args.wait:
try:
with NotificationServer(args.pid, args.timeout) as notifications:
if args.verbose:
print("Sending USR1 signal")
os.kill(args.pid, signal.SIGUSR1)
try:
ready = False
while not ready:
data = notifications.receive()
for data in data.split(b"\n"):
if args.verbose:
if data in (b"READY=1", b"RELOADING=1",
b"STOPPING=1"):
print("Process is %s" %
data.decode("ascii")[:-2])
else:
print("Received notification %r" % data)
if data == b"READY=1":
ready = True
except socket.timeout:
print("Timed out reloading %s" % script, file=sys.stderr)
exit(EXIT_RELOAD_TIMEOUT)
except OSError as e:
print("Could not bind notification socket: %s" % e,
file=sys.stderr)
exit(EXIT_RELOAD_FAILED)
else: # --no-wait
if args.verbose:
print("Sending USR1 signal")
os.kill(args.pid, signal.SIGUSR1)
print("Reloaded %s" % script)
if __name__ == "__main__":
main()
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