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mirror of https://github.com/ARM-software/devlib.git synced 2025-01-31 02:00:45 +00:00
devlib/devlib/connection.py
Jonathan Paynter 33397649b6 connection,targets: enable file transfer polling
For connections that allow for it (ADB and SSH using SFTP
and SCP) this change enables file transfers to be polled to check
if the transfer is still in progress after some period of time or
whether the transfer should be terminated.

If a timeout is specified in the call to ``pull`` or ``push`` then the
transfer will not be polled and will terminate ordinarily when either
the transfer completes or the timeout is reached. If a timeout is
not specified, then the transfer will be polled if ``poll_transfers`` is
set, otherwise the transfer will continue with no timeout at all.

SSH transfers supply a callback to the transfer, that is called
after every block of the source is transferred. If the callback has not
been triggered within one poll period, then the transfer is cancelled.

ADB transfers have the destination size polled every poll period, and
the size compared to the previous poll to check if the transfer has
stalled. When the destination is no longer growing in size, the poller
will attempt to kill the subprocess to end the transfer.

If the transfer is still active, but the total transfer time has
exceeded the ``total_timeout`` (default: 1 hour) the transfer will then
also be killed.

Transfer polling will only begin after the ``start_transfer_poll_delay``
time has elapsed.

Polling periods that are too small may incorrectly cancel transfers.
2020-11-03 10:01:43 +00:00

523 lines
15 KiB
Python

# Copyright 2019 ARM Limited
#
# 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.
#
from abc import ABC, abstractmethod
from contextlib import contextmanager
from datetime import datetime
from functools import partial
from weakref import WeakSet
from shlex import quote
from time import monotonic
import os
import signal
import socket
import subprocess
import threading
import time
import logging
from devlib.utils.misc import InitCheckpoint
_KILL_TIMEOUT = 3
def _kill_pgid_cmd(pgid, sig):
return 'kill -{} -{}'.format(sig.value, pgid)
class ConnectionBase(InitCheckpoint):
"""
Base class for all connections.
"""
def __init__(self):
self._current_bg_cmds = WeakSet()
self._closed = False
self._close_lock = threading.Lock()
self.busybox = None
def cancel_running_command(self):
bg_cmds = set(self._current_bg_cmds)
for bg_cmd in bg_cmds:
bg_cmd.cancel()
@abstractmethod
def _close(self):
"""
Close the connection.
The public :meth:`close` method makes sure that :meth:`_close` will
only be called once, and will serialize accesses to it if it happens to
be called from multiple threads at once.
"""
def close(self):
# Locking the closing allows any thread to safely call close() as long
# as the connection can be closed from a thread that is not the one it
# started its life in.
with self._close_lock:
if not self._closed:
self._close()
self._closed = True
# Ideally, that should not be relied upon but that will improve the chances
# of the connection being properly cleaned up when it's not in use anymore.
def __del__(self):
# Since __del__ will be called if an exception is raised in __init__
# (e.g. we cannot connect), we only run close() when we are sure
# __init__ has completed successfully.
if self.initialized:
self.close()
class BackgroundCommand(ABC):
"""
Allows managing a running background command using a subset of the
:class:`subprocess.Popen` API.
Instances of this class can be used as context managers, with the same
semantic as :class:`subprocess.Popen`.
"""
@abstractmethod
def send_signal(self, sig):
"""
Send a POSIX signal to the background command's process group ID
(PGID).
:param signal: Signal to send.
:type signal: signal.Signals
"""
def kill(self):
"""
Send SIGKILL to the background command.
"""
self.send_signal(signal.SIGKILL)
@abstractmethod
def cancel(self, kill_timeout=_KILL_TIMEOUT):
"""
Try to gracefully terminate the process by sending ``SIGTERM``, then
waiting for ``kill_timeout`` to send ``SIGKILL``.
"""
@abstractmethod
def wait(self):
"""
Block until the background command completes, and return its exit code.
"""
@abstractmethod
def poll(self):
"""
Return exit code if the command has exited, None otherwise.
"""
@property
@abstractmethod
def stdin(self):
"""
File-like object connected to the background's command stdin.
"""
@property
@abstractmethod
def stdout(self):
"""
File-like object connected to the background's command stdout.
"""
@property
@abstractmethod
def stderr(self):
"""
File-like object connected to the background's command stderr.
"""
@property
@abstractmethod
def pid(self):
"""
Process Group ID (PGID) of the background command.
Since the command is usually wrapped in shell processes for IO
redirections, sudo etc, the PID cannot be assumed to be the actual PID
of the command passed by the user. It's is guaranteed to be a PGID
instead, which means signals sent to it as such will target all
subprocesses involved in executing that command.
"""
@abstractmethod
def close(self):
"""
Close all opened streams and then wait for command completion.
:returns: Exit code of the command.
.. note:: If the command is writing to its stdout/stderr, it might be
blocked on that and die when the streams are closed.
"""
def __enter__(self):
return self
def __exit__(self, *args, **kwargs):
self.close()
class PopenBackgroundCommand(BackgroundCommand):
"""
:class:`subprocess.Popen`-based background command.
"""
def __init__(self, popen):
self.popen = popen
def send_signal(self, sig):
return os.killpg(self.popen.pid, sig)
@property
def stdin(self):
return self.popen.stdin
@property
def stdout(self):
return self.popen.stdout
@property
def stderr(self):
return self.popen.stderr
@property
def pid(self):
return self.popen.pid
def wait(self):
return self.popen.wait()
def poll(self):
return self.popen.poll()
def cancel(self, kill_timeout=_KILL_TIMEOUT):
popen = self.popen
os.killpg(os.getpgid(popen.pid), signal.SIGTERM)
try:
popen.wait(timeout=_KILL_TIMEOUT)
except subprocess.TimeoutExpired:
os.killpg(os.getpgid(popen.pid), signal.SIGKILL)
def close(self):
self.popen.__exit__(None, None, None)
return self.popen.returncode
def __enter__(self):
self.popen.__enter__()
return self
def __exit__(self, *args, **kwargs):
self.popen.__exit__(*args, **kwargs)
class ParamikoBackgroundCommand(BackgroundCommand):
"""
:mod:`paramiko`-based background command.
"""
def __init__(self, conn, chan, pid, as_root, stdin, stdout, stderr, redirect_thread):
self.chan = chan
self.as_root = as_root
self.conn = conn
self._pid = pid
self._stdin = stdin
self._stdout = stdout
self._stderr = stderr
self.redirect_thread = redirect_thread
def send_signal(self, sig):
# If the command has already completed, we don't want to send a signal
# to another process that might have gotten that PID in the meantime.
if self.poll() is not None:
return
# Use -PGID to target a process group rather than just the process
# itself
cmd = _kill_pgid_cmd(self.pid, sig)
self.conn.execute(cmd, as_root=self.as_root)
@property
def pid(self):
return self._pid
def wait(self):
return self.chan.recv_exit_status()
def poll(self):
if self.chan.exit_status_ready():
return self.wait()
else:
return None
def cancel(self, kill_timeout=_KILL_TIMEOUT):
self.send_signal(signal.SIGTERM)
# Check if the command terminated quickly
time.sleep(10e-3)
# Otherwise wait for the full timeout and kill it
if self.poll() is None:
time.sleep(kill_timeout)
self.send_signal(signal.SIGKILL)
self.wait()
@property
def stdin(self):
return self._stdin
@property
def stdout(self):
return self._stdout
@property
def stderr(self):
return self._stderr
def close(self):
for x in (self.stdin, self.stdout, self.stderr):
if x is not None:
x.close()
exit_code = self.wait()
thread = self.redirect_thread
if thread:
thread.join()
return exit_code
class AdbBackgroundCommand(BackgroundCommand):
"""
``adb``-based background command.
"""
def __init__(self, conn, adb_popen, pid, as_root):
self.conn = conn
self.as_root = as_root
self.adb_popen = adb_popen
self._pid = pid
def send_signal(self, sig):
self.conn.execute(
_kill_pgid_cmd(self.pid, sig),
as_root=self.as_root,
)
@property
def stdin(self):
return self.adb_popen.stdin
@property
def stdout(self):
return self.adb_popen.stdout
@property
def stderr(self):
return self.adb_popen.stderr
@property
def pid(self):
return self._pid
def wait(self):
return self.adb_popen.wait()
def poll(self):
return self.adb_popen.poll()
def cancel(self, kill_timeout=_KILL_TIMEOUT):
self.send_signal(signal.SIGTERM)
try:
self.adb_popen.wait(timeout=_KILL_TIMEOUT)
except subprocess.TimeoutExpired:
self.send_signal(signal.SIGKILL)
self.adb_popen.kill()
def close(self):
self.adb_popen.__exit__(None, None, None)
return self.adb_popen.returncode
def __enter__(self):
self.adb_popen.__enter__()
return self
def __exit__(self, *args, **kwargs):
self.adb_popen.__exit__(*args, **kwargs)
class TransferManagerBase(ABC):
def _pull_dest_size(self, dest):
if os.path.isdir(dest):
return sum(
os.stat(os.path.join(dirpath, f)).st_size
for dirpath, _, fnames in os.walk(dest)
for f in fnames
)
else:
return os.stat(dest).st_size
return 0
def _push_dest_size(self, dest):
cmd = '{} du -s {}'.format(quote(self.conn.busybox), quote(dest))
out = self.conn.execute(cmd)
try:
return int(out.split()[0])
except ValueError:
return 0
def __init__(self, conn, poll_period, start_transfer_poll_delay, total_timeout):
self.conn = conn
self.poll_period = poll_period
self.total_timeout = total_timeout
self.start_transfer_poll_delay = start_transfer_poll_delay
self.logger = logging.getLogger('FileTransfer')
self.managing = threading.Event()
self.transfer_started = threading.Event()
self.transfer_completed = threading.Event()
self.transfer_aborted = threading.Event()
self.monitor_thread = None
self.sources = None
self.dest = None
self.direction = None
@abstractmethod
def _cancel(self):
pass
def cancel(self, reason=None):
msg = 'Cancelling file transfer {} -> {}'.format(self.sources, self.dest)
if reason is not None:
msg += ' due to \'{}\''.format(reason)
self.logger.warning(msg)
self.transfer_aborted.set()
self._cancel()
@abstractmethod
def isactive(self):
pass
@contextmanager
def manage(self, sources, dest, direction):
try:
self.sources, self.dest, self.direction = sources, dest, direction
m_thread = threading.Thread(target=self._monitor)
self.transfer_completed.clear()
self.transfer_aborted.clear()
self.transfer_started.set()
m_thread.start()
yield self
except BaseException:
self.cancel(reason='exception during transfer')
raise
finally:
self.transfer_completed.set()
self.transfer_started.set()
m_thread.join()
self.transfer_started.clear()
self.transfer_completed.clear()
self.transfer_aborted.clear()
def _monitor(self):
start_t = monotonic()
self.transfer_completed.wait(self.start_transfer_poll_delay)
while not self.transfer_completed.wait(self.poll_period):
if not self.isactive():
self.cancel(reason='transfer inactive')
elif monotonic() - start_t > self.total_timeout:
self.cancel(reason='transfer timed out')
class PopenTransferManager(TransferManagerBase):
def __init__(self, conn, poll_period=30, start_transfer_poll_delay=30, total_timeout=3600):
super().__init__(conn, poll_period, start_transfer_poll_delay, total_timeout)
self.transfer = None
self.last_sample = None
def _cancel(self):
if self.transfer:
self.transfer.cancel()
self.transfer = None
def isactive(self):
size_fn = self._push_dest_size if self.direction == 'push' else self._pull_dest_size
curr_size = size_fn(self.dest)
self.logger.debug('Polled file transfer, destination size {}'.format(curr_size))
active = True if self.last_sample is None else curr_size > self.last_sample
self.last_sample = curr_size
return active
def set_transfer_and_wait(self, popen_bg_cmd):
self.transfer = popen_bg_cmd
ret = self.transfer.wait()
if ret and not self.transfer_aborted.is_set():
raise subprocess.CalledProcessError(ret, self.transfer.popen.args)
elif self.transfer_aborted.is_set():
raise TimeoutError(self.transfer.popen.args)
class SSHTransferManager(TransferManagerBase):
def __init__(self, conn, poll_period=30, start_transfer_poll_delay=30, total_timeout=3600):
super().__init__(conn, poll_period, start_transfer_poll_delay, total_timeout)
self.transferer = None
self.progressed = False
self.transferred = None
self.to_transfer = None
def _cancel(self):
self.transferer.close()
def isactive(self):
progressed = self.progressed
self.progressed = False
msg = 'Polled transfer: {}% [{}B/{}B]'
pc = format((self.transferred / self.to_transfer) * 100, '.2f')
self.logger.debug(msg.format(pc, self.transferred, self.to_transfer))
return progressed
@contextmanager
def manage(self, sources, dest, direction, transferer):
with super().manage(sources, dest, direction):
try:
self.progressed = False
self.transferer = transferer # SFTPClient or SCPClient
yield self
except socket.error as e:
if self.transfer_aborted.is_set():
self.transfer_aborted.clear()
method = 'SCP' if self.conn.use_scp else 'SFTP'
raise TimeoutError('{} {}: {} -> {}'.format(method, self.direction, sources, self.dest))
else:
raise e
def progress_cb(self, *args):
if self.transfer_started.is_set():
self.progressed = True
if len(args) == 3: # For SCPClient callbacks
self.transferred = args[2]
self.to_transfer = args[1]
elif len(args) == 2: # For SFTPClient callbacks
self.transferred = args[0]
self.to_transfer = args[1]