From: Euan Harris <euan.harris@citrix.com>
To: xen-devel@lists.xenproject.org
Cc: Euan Harris <euan.harris@citrix.com>, marmarek@invisiblethingslab.com
Subject: [PATCH v3 0/3] python: Add non-blocking Xenstore watch bindings
Date: Fri, 22 Sep 2017 17:21:11 +0100 [thread overview]
Message-ID: <1506097274-130806-1-git-send-email-euan.harris@citrix.com> (raw)
Expose xs_fileno() and xs_check_watch() to Python. These functions
make it posible to write event-driven Xenstore clients in Python:
#!/usr/bin/env python
import xen.lowlevel.xs
import sys
import errno
from select import select
import time
# Connect to XenStore and set watch
xsh = xen.lowlevel.xs.xs()
xsh.watch("/foo", "footoken")
xsh.watch("/bar", "bartoken")
# Start polling loop
xsfd = xsh.fileno()
while True:
readable, writable, exceptional = select([xsfd], [], [xsfd], 1.0)
print "%d tick" % time.time()
if readable:
while True:
watch = xsh.check_watch()
if not watch:
break
path, token = watch
print "%d watch fired: path=%s, token=%s" % (time.time(),
path, token)
value = xsh.read("", path)
print "%d read %s = %s" % (time.time(), path, value)
if exceptional:
print "select error"
The polling loop can be simplified further by wrapping the call to
xsh.check_watch() in a generator, but this is easier to do in Python
than in the C bindings.
Euan Harris (3):
python: Add binding for xs_fileno()
python: Extract registered watch search logic from xspy_read_watch()
python: Add binding for non-blocking xs_check_watch()
tools/python/xen/lowlevel/xs/xs.c | 108 ++++++++++++++++++++++++++++++--------
1 file changed, 85 insertions(+), 23 deletions(-)
--
1.8.3.1
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next reply other threads:[~2017-09-22 16:21 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-22 16:21 Euan Harris [this message]
2017-09-22 16:21 ` [PATCH v3 1/3] python: Add binding for xs_fileno() Euan Harris
2017-09-22 17:50 ` Marek Marczykowski-Górecki
2017-09-25 8:40 ` Wei Liu
2017-09-22 16:21 ` [PATCH v3 2/3] python: Extract registered watch search logic from xspy_read_watch() Euan Harris
2017-09-22 16:21 ` [PATCH v3 3/3] python: Add binding for non-blocking xs_check_watch() Euan Harris
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