#!/usr/bin/env python
# PySys System Test Framework, Copyright (C) 2006-2020 M.B. Grieve
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
"""
Dynamic TCP port allocation.
This is used by the `pysys.process.user.ProcessUser` class (and its subclasses e.g. BaseTest) which should
usually be used to access this functionality.
"""
import collections, random, subprocess, sys
import io
import logging
import time
import platform
from pysys import process_lock
from pysys.constants import *
from pysys.utils.fileutils import openfile
# LRU queue of server TCP ports for allocation to tests which need to
# start TCP servers. Initialized to None since it might not actually be used.
# Properly initialize only on demand.
tcpServerPortPool = None
_log = logging.getLogger('pysys.allocport')
[docs]def getEphemeralTCPPortRange():
"""Returns the minimum and maximum TCP ports this operating system uses to allocate
ephemeral/dynamic ports (the client side of the TCP connection).
This function is used by `getServerTCPPorts()` to ensure that no ephemeral/client-side ports are allocated for
server-side purposes by PySys (this could cause random port clashes).
If the available server ports are overridden using the ``PYSYS_PORTS`` or ``PYSYS_PORTS_FILE`` environment
variables, this function is not called.
:return: A tuple (ephemeral_min: int, ephemeral_max: int) giving the ephemeral port range for this platform.
:raises Exception: If the ephemeral port range cannot be determined, which will prevent PySys from running any tests.
"""
# Find the smallest and largest ephemeral port
if PLATFORM == 'linux':
port_file = '/proc/sys/net/ipv4/ip_local_port_range'
if not os.path.exists(port_file):
# There's no perfect default that works for all OSes (and the config may be customized by the OS anyway),
# but it's useful to avoid an error to help on environments like Windows Subsystem for Linux v1.
# We pick the IANA range as our default
ephemeral_low, ephemeral_high = 49152, 65535
_log.warning('PySys cannot determine the local/ephemeral port range on this OS (%s) as "%s" is missing; falling back to default IANA range %d-%d. Consider using the PYSYS_PORTS=minport-maxport environment variable to explicitly configure the range of non-ephemeral/server ports for PySys to use.', platform.platform(), port_file, ephemeral_low, ephemeral_high)
else:
with openfile(port_file) as f:
s = f.readline().split()
ephemeral_low = int(s[0])
ephemeral_high = int(s[1])
elif PLATFORM == 'sunos':
def runNdd(driver, parameter):
p = subprocess.Popen(['/usr/sbin/ndd', driver, parameter], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
return int(p.communicate()[0].strip())
ephemeral_low = runNdd('/dev/tcp', 'tcp_smallest_anon_port')
ephemeral_high = runNdd('/dev/tcp', 'tcp_largest_anon_port')
elif PLATFORM == 'darwin':
def runSysctl(parameter):
p = subprocess.Popen(['/usr/sbin/sysctl', '-n', parameter], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
return int(p.communicate()[0].strip())
ephemeral_low = runSysctl('net.inet.ip.portrange.first')
ephemeral_high = runSysctl('net.inet.ip.portrange.last')
elif PLATFORM == 'win32':
try:
# The port defaults have changed in various windows releases, so executing this command is the most reliable solution
# We assume that IPv6 (if used) is configured the same
netsh = subprocess.check_output(['netsh', 'int', 'ipv4', 'show', 'dynamicport', 'tcp'])
ephemeral_low = int(re.search(b'Start Port *: *([0-9]+)', netsh).group(1))
ephemeral_high = int(re.search(b'Number of Ports *: *([0-9]+)', netsh).group(1)) + ephemeral_low
except Exception as ex:
# This is a fallback just in case the above command doesn't work
_log.debug('Failed to get Windows dynamic port range using netsh - %s: %s', type(ex).__name__, ex)
ephemeral_low = 1025
ephemeral_high = 5000 # The default
if sys.version_info[0] == 2:
import _winreg as winreg
else:
import winreg
with winreg.OpenKey(winreg.HKEY_LOCAL_MACHINE, r'SYSTEM\CurrentControlSet\Services\Tcpip\Parameters') as h:
try:
ephemeral_high = winreg.QueryValueEx(h, 'MaxUserPort')[0]
_log.debug('Read ephemeral_high value from MaxUserPort in registry: %s', ephemeral_high)
except Exception:
# Accept the default if there isn't a value in the registry
pass
if ephemeral_high > 65535-100:
# this suggests we're on one of the more recent OSes which use the IANA range rather than the low 1025+
# part of the range for ephemeral ports (and anyway, we'd end up
# with no non-dynamic ports on which to start servers on if we didn't do this!)
ephemeral_low = 49152
_log.debug('Forcing ephemeral_low to %s since with ephemeral_high=%s there would be no server ports otherwise',
ephemeral_low, ephemeral_high)
else:
raise Exception("PySys cannot determine the ephemeral port range on platform %s (consider using the PYSYS_PORTS=min-max or PYSYS_PORTS_FILE= environment variables)" % sys.platform)
assert ephemeral_low <= ephemeral_high, [ephemeral_low, ephemeral_high]
return (ephemeral_low, ephemeral_high)
[docs]def getServerTCPPorts():
"""Returns a list of the TCP ports that PySys tests can use when starting servers that listen on a port.
This function is usually called when `pysys.baserunner.BaseRunner` is constructed to help decide the
pool of available ports that can be allocated by `pysys.basetest.BaseTest.getNextAvailableTCPPort()`.
PySys treats all ports from 1024-65536 as server ports except for the client-side ephemeral/dynamic port range
as determined by `getEphemeralTCPPortRange()`. Alternatively, the set of server ports can be overridden by the
following environment variables:
- ``PYSYS_PORTS=minport-maxport,port,...`` PySys will use the specified ports and/or port ranges (inclusive)
allocating server ports.
- ``PYSYS_PORTS_FILE=file_path.txt`` PySys will use ports from the specified ASCII text file, one port per line.
If using these variables, be sure to avoid none of the ports reserved for ephemeral use is in the set of server
ports you specify.
:return: A list or set of all the server ports that can be used, e.g. [1024, 1025, ...].
:raises Exception: If the port range cannot be determined, which will prevent PySys from running any tests.
"""
if os.getenv('PYSYS_PORTS', None):
specs = os.environ['PYSYS_PORTS'].split(',')
elif os.getenv('PYSYS_PORTS_FILE',None):
with io.open(os.environ['PYSYS_PORTS_FILE'], 'r', encoding='utf-8') as f:
specs = f.readlines()
else:
ephemeral_low, ephemeral_high = getEphemeralTCPPortRange()
# The standard implementation: allocate server ports from all non-privileged, non-ephemeral ports
ports = list(range(1024, ephemeral_low)) + list(range(ephemeral_high,65536))
_log.debug('TCP ephemeral port range is: %d-%d; this leaves a total of %d ports for running servers', ephemeral_low, ephemeral_high, len(ports))
if len(ports)<50:
fallback_low, fallback_high = (1024, 49152-1)
_log.warning('PySys has detected that only %d ports are remaining for starting servers, after removing the %d-%d ephemeral/dynamic port range on this machine (%s). To ensure enough ports are available, PySys is falling back to using the server port range %d-%d, however this may result in clashes between server ports and ephemeral ports so it is recommended to change your TCP configuration on this machine to provide more balance between the number of ephemeral vs server ports. ', len(ports), ephemeral_low, ephemeral_high, platform.platform(), fallback_low, fallback_high)
ports = list(range(fallback_low, fallback_high+1))
return ports
ports = set()
for x in specs:
x = x.strip()
if len(x)==0: continue
if '-' in x:
envrange = x.split('-')
for p in range(int(envrange[0].strip()), int(envrange[1].strip())+1):
ports.add(p)
else:
ports.add(int(x.strip()))
return ports
def initializePortPool():
"""Initialize the pool of ports we can allocate TCP server ports from
i.e. ports that processes can bind to without clashes with other
processes.
Called from BaseRuner.__init__ (not when this module is imported) so that it's possible to monkey-patch
getEphemeralTCPPortRange() in user code (e.g. when the custom runner is imported) if required e.g. for a new platform.
:meta private: Not public API
"""
global tcpServerPortPool
assert tcpServerPortPool is None, 'Cannot call initializePortPool() more than once per process'
tcpServerPortPool = list(getServerTCPPorts())
# Randomize the port set to reduce the chance of clashes between
# simultaneous runs on the same machine
random.shuffle(tcpServerPortPool)
# Convert to an LRU queue of ports
tcpServerPortPool = collections.deque(tcpServerPortPool)
def portIsInUse(port, host='', socketAddressFamily=socket.AF_INET, type=socket.SOCK_STREAM, proto=0):
# Try to bind to the post on the specified address to see if anyone else is using it
with process_lock:
s = socket.socket(socketAddressFamily, type, proto=proto)
try:
# Set SO_LINGER since we don't want any accidentally
# connecting clients to cause the socket to hang
# around
if IS_WINDOWS:
s.setsockopt(socket.SOL_SOCKET, socket.SO_LINGER, 0)
# Set non-blocking since we want to fail fast rather
# than block
s.setblocking(0)
try:
s.bind( (host, port) )
except Exception as e:
# If we get any exception assume it is because
# the port is in use
return True
# Listen may not be necessary, but on unix it seems to
# help do a more complete shutdown if listen is called
s.listen(1)
try:
s.shutdown(socket.SHUT_RDWR)
except Exception:
# Do nothing - on windows shutdown sometimes
# fails even after listen
pass
except Exception as e:
# Don't expect this but just in case
_log.error('Exception from port allocator portIsInUse check for %s:%d - %s: %s', host or 'INADDR_ANY', port, e.__class__.__name__, e)
return True
finally:
s.close()
return False
def allocateTCPPort(hosts=['', 'localhost'], socketAddressFamily=socket.AF_INET, type=socket.SOCK_STREAM, proto=0):
# nb: expose socket type and protocol number here but not higher up the stack just in case someone needs them, but
# not very likely
t = time.time()
haslogged = False
while time.time()-t < TIMEOUTS['WaitForAvailableTCPPort']:
# in case we've allocated all the available ports, loop
# until another test terminates and free up some ports
try:
port = tcpServerPortPool.popleft()
except Exception:
time.sleep(2)
if not haslogged:
# Useful to know about this as it shouldn't really happen if the TCP stack is configured in a sane way
# and the tests aren't not leaking ports
_log.warning('Unable to allocate a TCP port yet as all are in use by PySys; will wait for up to %0.1fs', TIMEOUTS['WaitForAvailableTCPPort'])
haslogged = True
continue
if any(portIsInUse(port, socketAddressFamily=socketAddressFamily, type=type, proto=proto, host=host) for host in hosts):
# Toss the port back at the end of the queue
tcpServerPortPool.append(port)
time.sleep(0.5) # avoid spinning
else:
if haslogged:
_log.info(' successfully allocated TCP port %d after %0.1fs', port, time.time()-t)
return port
raise Exception('Timed out trying to allocate a free TCP server port after %0.1f secs; other tests are currently using all the available ports (hint: check that PySys has correctly detected the range of ephemeral vs server ports by running with -vDEBUG)'%TIMEOUTS['WaitForAvailableTCPPort'])
[docs]class TCPPortOwner(object):
"""
Class that allocates a free server port when constructed,
and returns it to the pool of available ports when `cleanup` is called.
:param list(Str) hosts: A list of the host names or IP addresses to check when establishing that a potential
allocated port isn't already in use by a process outside the PySys framework.
By default we check ``""`` (which corresponds to ``INADDR_ANY`` and depending on the OS means
either one or all non-localhost IPv4 addresses) and also ``localhost``.
Many machines have multiple network cards each with its own host IP address, and typically you'll only be using
one of them in your test, most commonly ``localhost``. If you do know which host/IP you'll actually be using,
just specify that directly to save time, and avoid needlessly opening remote ports on hosts you're not using.
A list of available host addresses and corresponding family/type/proto can be found from
``socket.getaddrinfo('', None)``.
:param int socketAddressFamily: The address family to use when checking if the port is in use, e.g. to indicate
IPv4 vs IPv6. See ``socket.socket`` in the Python standard library for more information.
:ivar int ~.port: The port allocated and owned by this instance.
"""
def __init__(self, hosts=['', 'localhost'], socketAddressFamily=socket.AF_INET):
self.port = allocateTCPPort(hosts=hosts, socketAddressFamily=socketAddressFamily)
[docs] def cleanup(self):
"""Must be called when this port is no longer needed to return it to PySys' pool of available ports.
"""
tcpServerPortPool.append(self.port)