Commit 0c16ca07 authored by kaliko's avatar kaliko
Browse files

Add socket timeout

parent a8a20607
Pipeline #333403013 passed with stages
in 1 minute and 44 seconds
python-musicpd Changes List
===========================
Changes in 0.6.1
Changes in 0.7.0
----------------
* Add socket timeout (disabled by default)
* MPD_TIMEOUT is set for both tcp and unix sockets
* Raises an exception if command contains '\n'
Changes in 0.6.0
----------------
......
......@@ -3,6 +3,8 @@ musicpd namespace
.. autodata:: musicpd.CONNECTION_TIMEOUT
.. autodata:: musicpd.SOCKET_TIMEOUT
.. autoclass:: musicpd.MPDClient
:members:
......
......@@ -35,7 +35,7 @@ The client honors the following environment variables:
| For abstract socket use "@" as prefix : "`@socket`" and then with a password "`pass@@socket`"
| Regular unix socket are set with an absolute path: "`/run/mpd/socket`"
* ``MPD_PORT`` MPD port, relevant for TCP socket only, ie with :abbr:`FQDN (fully qualified domain name)` defined host
* ``MPD_TIMEOUT`` timeout for connecting to MPD and for waiting for MPD’s response in seconds
* ``MPD_TIMEOUT`` timeout for connecting to MPD and waiting for MPD’s response in seconds
* ``XDG_RUNTIME_DIR`` path to look for potential socket: ``${XDG_RUNTIME_DIR}/mpd/socket``
Defaults settings
......@@ -172,4 +172,68 @@ You can also use `readpicture` command to fetch embedded picture:
Refer to `MPD protocol documentation`_ for the meaning of `binary`, `size` and `data`.
Socket timeout
--------------
.. note::
When the timeout is reached it raises a :py:obj:`socket.timeout` exception. An :py:obj:`OSError` subclass.
A timeout is used for the initial MPD connection (``connect`` command), then
the socket is put in blocking mode with no timeout. Its value is set in
:py:obj:`musicpd.CONNECTION_TIMEOUT` at module level and
:py:obj:`musicpd.MPDClient.mpd_timeout` in MPDClient instances . However it
is possible to set socket timeout for all command setting
:py:obj:`musicpd.MPDClient.socket_timeout` attribute to a value in second.
Having ``socket_timeout`` enabled can help to detect "half-open connection".
For instance loosing connectivity without the server explicitly closing the
connection (switching network interface ethernet/wifi, router down, etc…).
**Nota bene**: with ``socket_timeout`` enabled each command sent to MPD might
timeout. A couple of seconds should be enough for commands to complete except
for the special case of ``idle`` command which by definition *“ waits until
there is a noteworthy change in one or more of MPD’s subsystems.”* (cf. `MPD
protocol documentation`_).
Here is a solution to use ``idle`` command with ``socket_timeout``:
.. code-block:: python
import musicpd
import select
import socket
cli = musicpd.MPDClient()
try:
cli.socket_timeout = 10 # seconds
select_timeout = 5 # second
cli.connect()
while True:
cli.send_idle() # use send_ API to avoid blocking on read
_read, _, _ = select.select([cli], [], [], select_timeout)
if _read: # tries to read response
ret = cli.fetch_idle()
print(', '.join(ret)) # Do something
else: # cancels idle
cli.noidle()
except socket.timeout as err:
print(f'{err} (timeout {cli.socket_timeout})')
except KeyboardInterrupt:
pass
Some explanations:
* First launch a non blocking ``idle`` command. This call do not wait for a
response to avoid socket timeout waiting for an MPD event.
* ``select`` waits for something to read on the socket (the idle response
in this case), returns after ``select_timeout`` seconds anyway.
* In case there is something to read read it using ``fetch_idle``
* Nothing to read, cancel idle with ``noidle``
All three commands in the while loop (send_idle, fetch_idle, noidle) are not
triggering a socket timeout unless the connection is actually lost (actually it
could also be that MPD took to much time to answer, but MPD taking more than a
couple of seconds for these commands should never occur).
.. _MPD protocol documentation: http://www.musicpd.org/doc/protocol/
......@@ -28,10 +28,12 @@ HELLO_PREFIX = "OK MPD "
ERROR_PREFIX = "ACK "
SUCCESS = "OK"
NEXT = "list_OK"
VERSION = '0.6.1'
#: seconds before a tcp connection attempt times out (overriden by MPD_TIMEOUT env. var.)
VERSION = '0.7.0'
#: Seconds before a connection attempt times out
#: (overriden by MPD_TIMEOUT env. var.)
CONNECTION_TIMEOUT = 30
#: Socket timeout in second (Default is None for no timeout)
SOCKET_TIMEOUT = None
def iterator_wrapper(func):
......@@ -157,6 +159,11 @@ class MPDClient:
def __init__(self):
self.iterate = False
#: Socket timeout value in seconds
self._socket_timeout = SOCKET_TIMEOUT
#: Current connection timeout value, defaults to
#: :py:attr:`musicpd.MPD_TIMEOUT` or env. var. ``MPD_TIMEOUT`` if provided
self.mpd_timeout = None
self._reset()
self._commands = {
# Status Commands
......@@ -324,7 +331,7 @@ class MPDClient:
self.mpd_timeout = os.getenv('MPD_TIMEOUT')
if self.mpd_timeout and self.mpd_timeout.isdigit():
self.mpd_timeout = int(self.mpd_timeout)
else: # Use 30s default even is MPD_TIMEOUT carries gargage
else: # Use CONNECTION_TIMEOUT as default even if MPD_TIMEOUT carries gargage
self.mpd_timeout = CONNECTION_TIMEOUT
def __getattr__(self, attr):
......@@ -611,7 +618,9 @@ class MPDClient:
if path.startswith('@'):
path = '\0'+path[1:]
sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
sock.settimeout(self.mpd_timeout)
sock.connect(path)
sock.settimeout(self.socket_timeout)
return sock
def _connect_tcp(self, host, port):
......@@ -629,7 +638,7 @@ class MPDClient:
sock = socket.socket(af, socktype, proto)
sock.settimeout(self.mpd_timeout)
sock.connect(sa)
sock.settimeout(None)
sock.settimeout(self.socket_timeout)
return sock
except socket.error as socket_err:
err = socket_err
......@@ -658,14 +667,18 @@ class MPDClient:
The connect method honors MPD_HOST/MPD_PORT environment variables.
The underlying tcp socket also honors MPD_TIMEOUT environment variable
and defaults to :py:obj:`musicpd.CONNECTION_TIMEOUT`.
The underlying socket also honors MPD_TIMEOUT environment variable
and defaults to :py:obj:`musicpd.CONNECTION_TIMEOUT` (connect command only).
If you want to have a timeout for each command once you got connected,
set its value in :py:obj:`MPDClient.socket_timeout` (in second) or at
module level in :py:obj:`musicpd.SOCKET_TIMEOUT`.
.. note:: Default host/port
If host evaluate to :py:obj:`False`
* use ``MPD_HOST`` environment variable if set, extract password if present,
* else looks for a existing file in ``${XDG_RUNTIME_DIR:-/run/}/mpd/socket``
* else looks for an existing file in ``${XDG_RUNTIME_DIR:-/run/}/mpd/socket``
* else set host to ``localhost``
If port evaluate to :py:obj:`False`
......@@ -695,6 +708,18 @@ class MPDClient:
self.disconnect()
raise
@property
def socket_timeout(self):
"""Socket timeout in second (defaults to :py:obj:`SOCKET_TIMEOUT`).
Use None to disable socket timout."""
return self._socket_timeout
@socket_timeout.setter
def socket_timeout(self, timeout):
self._socket_timeout = timeout
if getattr(self._sock, 'settimeout', False):
self._sock.settimeout(self._socket_timeout)
def disconnect(self):
"""Closes the MPD connection.
The client closes the actual socket, it does not use the
......
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