def __init__(self, name, context):
"""Create a new channel to the named PV.
Note: This will _always_ start a new channel even
if one already exists.
"""
self.name, self._ctxt=name, context
self._connected=False # True, False, or None (shutdown)
self.status=CBManager() # connection status callback
self.__eventCon=DeferredManager()
self.__eventDis=DeferredManager()
self.__eventDis.callback(self) # initially disconnected
# Stores a deferred from the client during
# name and circuit lookup phases
self.__L=None
# Store a deferred during the attach phase
self._d=None
self.__T=None # reconnect delay timer
self._chan={18:self._channelOk,
22:self._rights,
26:self._channelFail,
27:self._disconn,
}
self.__Done=self._ctxt.onClose
self.__Done.addCallback(lambda _:self.close())
self._reset()
def __init__(self,
conf=Config.default,
user=None,
host=None,
reactor=reactor):
"""Construct a new client context
Prepare a new context with the given config.
If user and host are None then they are collected
from the environment.
"""
self.conf, self.reactor = conf, reactor
self.circuits = CACircuitFactory(self)
self.resolv = Resolver(self.circuits, conf)
self._onClose = DeferredManager()
if host is None:
from socket import gethostname
host = gethostname()
self.host = host
if user is None:
from getpass import getuser
user = getuser()
self.user = user
reactor.addSystemEventTrigger("before", "shutdown", self.close)
def __init__(self, server):
self.server=server
self.peer=self.tcpport=None
self.prio, self.version=0, 11
self.user,self.host="<NOONE>","<ANONYMOUS>"
self.in_buffer=''
self._circ={0 :self.caver,
1 :self.forwardchan,
2 :self.forwardchan,
4 :self.forwardchan,
12:self.clearchan,
15:self.forwardchan,
18:self.createchan,
19:self.forwardchan,
20:self.caclient,
21:self.cahost,
23:self.ping,
}
self.__C=DeferredManager()
self.__D=DeferredManager()
self.__D.callback(self)
self.channels={}
self.next_sid=0
def connectionLost(self, reason):
self.__C=DeferredManager()
D, self.__D = self.__D, None
D.callback(self)
self.server.circuits.remove(self)
log.debug('Destroy %s',self)
def restart(self, data):
"""Re-send with new value array
"""
if not self.done:
raise RuntimeError('Previous Set not complete')
self._data = data
self.done = False
self._comp = DeferredManager()
d = self.__D = self._chan.whenCon
d.addCallback(self._chanOk)
def connectionMade(self):
self.peer=self.transport.getPeer()
self.tcpport=self.transport.getHost().port
# before 3.14.12 servers didn't send version until client authenticated
# from 3.14.12 clients attempting to do TCP name resolution don't authenticate
# but expect a version message immediately
pkt=CAmessage(cmd=0, dtype=self.prio, count=defs.CA_VERSION)
self.send(pkt.pack())
log.debug('connection from %s',self.peer)
log.debug('Create %s',self)
self.server.circuits.add(self)
self.__D=DeferredManager()
self.__C.callback(self)
def restart(self):
"""Restart request
Send a new request to the server.
Note: A no-op if a request is currently in progress.
"""
if not self.done:
return
self.done = False
self._result = DeferredManager()
d = self.__D = self._chan.whenCon
d.addCallback(self._chanOk)
def attached(conn):
assert self._d is None, '_d must be None before callback'
if conn is None:
# Server died while we were attaching
return
elif conn is False:
# channel not present on server
log.info('channel %s rejected by server', self.name)
return
log.debug('Channel %s Open',self.name)
self.state=self.S_connect
self.__eventDis=DeferredManager()
self.__eventCon.callback(self)
self._connected=True
self.status(self, True)
class MockChannel(object):
implements(IChannel)
dbr = _circ = None
sid = cid = maxcount = 0
def __init__(self):
self._C = DeferredManager()
self._D = DeferredManager()
self._D.callback(None)
@property
def whenCon(self):
return self._C.get()
@property
def whenDis(self):
return self._D.get()
def doCon(self):
self._D = DeferredManager()
self._C.callback(self)
def doFail(self):
d, self._C = self._C, DeferredManager()
d.callback(None)
def doLost(self):
self._C = DeferredManager()
d, self._D = self._D, DeferredManager()
def _reset(self, _=None):
"""Reset to disconnected state
Safe to call in all states
"""
if self._connected is None:
# shutdown already happened
return
log.debug('Channel %s reset',self.name)
if self._connected is True:
# _d is cleared before _connected is True
assert self._d is None
self.status(self, False)
elif self._d:
d, self._d = self._d, None
d.callback(None)
if self.__L is not None:
self.__L.addErrback(lambda e:e.trap(CancelledError))
self.__L.cancel()
self.__L=None
self.cid=self.sid=self.dbr=None
self._circ=None
self.maxcount=self.rights=0
self.state=self.S_init
if self._connected:
self._connected=False
self.__eventCon=DeferredManager()
d, self._eventDis = self.__eventDis, None
d.callback(self)
if self.__T is None:
self.__T=reactor.callLater(self.reconnectDelay,
self._connect)
class CAClientChannel(object):
"""Persistent Client Channel
Handles lookups and (re)connection.
"""
implements(IDispatch, IConnectNotify)
S_init='Disconnected'
S_lookup='PV lookup'
S_waitcirc='Waiting for circuit'
S_attach='Creating channel'
S_connect='Connected'
reconnectDelay=0.1
def __init__(self, name, context):
"""Create a new channel to the named PV.
Note: This will _always_ start a new channel even
if one already exists.
"""
self.name, self._ctxt=name, context
self._connected=False # True, False, or None (shutdown)
self.status=CBManager() # connection status callback
self.__eventCon=DeferredManager()
self.__eventDis=DeferredManager()
self.__eventDis.callback(self) # initially disconnected
# Stores a deferred from the client during
# name and circuit lookup phases
self.__L=None
# Store a deferred during the attach phase
self._d=None
self.__T=None # reconnect delay timer
self._chan={18:self._channelOk,
22:self._rights,
26:self._channelFail,
27:self._disconn,
}
self.__Done=self._ctxt.onClose
self.__Done.addCallback(lambda _:self.close())
self._reset()
@property
def whenCon(self):
return self.__eventCon.get()
@property
def whenDis(self):
return self.__eventDis.get()
def close(self):
"""Close the channel.
This will fail any pending actions.
Once called channel can not be reused.
"""
if self._connected is None:
# shutdown already happened
return
log.debug('Channel %s close',self.name)
self.__Done.cancel()
self.__Done.addErrback(lambda e:e.trap(CancelledError))
self._reset()
if self.__T is not None:
assert self.__T.active(), 'Timer already expired/cancelled'
self.__T.cancel()
self.__T=None
if self._connected:
self.__eventDis.callback(self)
else:
self.__eventCon.callback(None)
self._connected=None
# post condition
# Both __eventDis and __eventCon are fired
# further connection attempts fail immediately
def _reset(self, _=None):
"""Reset to disconnected state
Safe to call in all states
"""
if self._connected is None:
# shutdown already happened
return
log.debug('Channel %s reset',self.name)
if self._connected is True:
# _d is cleared before _connected is True
assert self._d is None
self.status(self, False)
elif self._d:
d, self._d = self._d, None
d.callback(None)
if self.__L is not None:
self.__L.addErrback(lambda e:e.trap(CancelledError))
self.__L.cancel()
self.__L=None
self.cid=self.sid=self.dbr=None
self._circ=None
self.maxcount=self.rights=0
self.state=self.S_init
if self._connected:
self._connected=False
self.__eventCon=DeferredManager()
d, self._eventDis = self.__eventDis, None
d.callback(self)
if self.__T is None:
self.__T=reactor.callLater(self.reconnectDelay,
self._connect)
@property
def connected(self):
"""Test if the channel is currently connected
"""
return self._connected
@property
def running(self):
"""Test if the channel has been shut down
"""
return self._connected is not None
def _connect(self):
"""Start channel connection sequence
lookup -> open circuit -> attach channel -> connected
only safe to call from _reset()
"""
assert self._connected is False and self.state is self.S_init
# prevent error when cancelling.
# _connect is invoked when __T expires
self.__T=None
log.debug('Channel %s connecting...',self.name)
self.state=self.S_lookup
self.__L=self._ctxt.lookup(self.name)
self.__L.pause()
@self.__L.addCallback
def doneLookup(srv):
if srv is None:
# lookups only fail when the client is shutting down
return
self.state=self.S_waitcirc
log.debug('Found %s on %s',self.name,srv)
return self._ctxt.openCircuit(srv)
@self.__L.addCallback
def haveCircuit(circ):
self.__L=None
if circ is None:
# couldn't connect to server
self._reset()
return
self.state=self.S_attach
log.debug('Attaching %s to %s',self.name,circ)
# the circuit is passed only if in the connected state
# but it can drop at any time
self.__L=d=circ.transport.connector.whenDis
d.addCallback(self._circuitLost)
self._d=Deferred()
self._circ=circ
circ.addchan(self)
return self._d
@self.__L.addCallback
def attached(conn):
assert self._d is None, '_d must be None before callback'
if conn is None:
# Server died while we were attaching
return
elif conn is False:
# channel not present on server
log.info('channel %s rejected by server', self.name)
return
log.debug('Channel %s Open',self.name)
self.state=self.S_connect
self.__eventDis=DeferredManager()
self.__eventCon.callback(self)
self._connected=True
self.status(self, True)
self.__L.unpause()
return self.__L
def _circuitLost(self,_):
self.__L=None
log.debug('Channel %s lost circuit',self.name)
self._reset()
def _disconn(self, pkt, peer, circuit):
"""Server has stopped providing the channel
"""
log.warning('Server has disconnected %s',self.name)
self._reset()
def _channelOk(self, pkt, peer, circuit):
self.dbr, self.maxcount=pkt.dtype, pkt.count
self.sid=pkt.p2
self._checkReady()
def _channelFail(self, pkt, peer, circuit):
log.info('Server %s rejects channel %s',peer,self.name)
if self._d:
d, self._d = self._d, None
d.callback(False)
self._reset()
def _rights(self, pkt, peer, circuit):
self.rights=pkt.p2
self._checkReady()
def _checkReady(self):
"""Sometimes the access rights message preceeds the
ack of channel creation...
"""
if self.sid is None or self.rights is None:
return
if self._d:
d, self._d = self._d, None
d.callback(True)
def dispatch(self, pkt, circuit, peer=None):
assert circuit is self._circ
hdl=self._chan.get(pkt.cmd, self._ctxt.dispatch)
if hdl:
hdl(pkt, circuit, peer)
else:
log.debug('Channel %s received unknown %s',self.name,pkt)
def __str__(self):
return 'Channel %(name)s %(state)s %(cid)s:%(sid)s %(dbr)s %(maxcount)s'%self.__dict__
class CAcircuit(Protocol):
implements(IConnectNotify)
def __init__(self, server):
self.server=server
self.peer=self.tcpport=None
self.prio, self.version=0, 11
self.user,self.host="<NOONE>","<ANONYMOUS>"
self.in_buffer=''
self._circ={0 :self.caver,
1 :self.forwardchan,
2 :self.forwardchan,
4 :self.forwardchan,
12:self.clearchan,
15:self.forwardchan,
18:self.createchan,
19:self.forwardchan,
20:self.caclient,
21:self.cahost,
23:self.ping,
}
self.__C=DeferredManager()
self.__D=DeferredManager()
self.__D.callback(self)
self.channels={}
self.next_sid=0
@property
def whenCon(self):
return self.__C.get()
@property
def whenDis(self):
return self.__D.get()
def dropchan(self, channel):
assert channel.sid in self.channels
self.channels.pop(channel.sid)
# CA actions
def caver(self, pkt, x, y):
self.version=min(defs.CA_VERSION, pkt.count)
self.prio=pkt.dtype
log.debug('Version %s',self)
def caclient(self, pkt, x, y):
self.user=str(pkt.body).strip('\0')
log.debug('Update %s',self)
def cahost(self, pkt, x, y):
self.host=str(pkt.body).strip('\0')
# do reverse lookup
host, aliases, z = socket.gethostbyaddr(self.peer.host)
if self.host!=host and self.host not in aliases:
log.warning("""Demoting connection from %s
reverse lookup against %s failed""",self.peer.host,self.host)
self.host='<ANONYMOUS>'
return
log.debug('Update %s',self)
def createchan(self, pkt, x, y):
# Older clients first report version here
self.version=pkt.p2
name=str(pkt.body).strip('\0')
pv = self.server.GetPV(name)
if pv is None:
# PV does not exist
log.debug("Can't create channel for non-existant PV %s",name)
fail = CAmessage(cmd=26, p1=pkt.p1)
self.send(fail.pack())
return
chan=Channel(self.next_sid, pkt.p1, self.server, self, pv)
self.channels[chan.sid]=chan
dtype, maxcount = pv.info(chan)
ok = CAmessage(cmd=18, dtype=dtype, count=maxcount,
p1=pkt.p1, p2=chan.sid)
rights = CAmessage(cmd=22, p1=pkt.p1, p2=chan.rights)
self.send(ok.pack()+rights.pack())
self.next_sid=self.next_sid+1
while self.next_sid in self.channels:
self.next_sid=self.next_sid+1
def clearchan(self, pkt, x, y):
chan=self.channels.get(pkt.p1)
if not chan:
log.warning('Attempt to clean non-existent channel')
return
chan.close()
ok = CAmessage(cmd=12, p1=pkt.p1, p2=pkt.p2)
self.send(ok.pack())
def forwardchan(self, pkt, peer, circuit):
chan=self.channels.get(pkt.p1)
if not chan:
log.warning('Attempt to access non-existent channel')
return
chan.dispatch(pkt, peer, circuit)
def ping(self, pkt, x, y):
self.send(pkt.pack())
# socket operations
def connectionMade(self):
self.peer=self.transport.getPeer()
self.tcpport=self.transport.getHost().port
# before 3.14.12 servers didn't send version until client authenticated
# from 3.14.12 clients attempting to do TCP name resolution don't authenticate
# but expect a version message immediately
pkt=CAmessage(cmd=0, dtype=self.prio, count=defs.CA_VERSION)
self.send(pkt.pack())
log.debug('connection from %s',self.peer)
log.debug('Create %s',self)
self.server.circuits.add(self)
self.__D=DeferredManager()
self.__C.callback(self)
def connectionLost(self, reason):
self.__C=DeferredManager()
D, self.__D = self.__D, None
D.callback(self)
self.server.circuits.remove(self)
log.debug('Destroy %s',self)
def connectionFailed(self, reason):
C, self.__C = self.__C, DeferredManager()
C.callback(None)
def send(self, msg):
self.transport.write(msg)
def sendto(self, msg, peer=None):
self.transport.write(msg)
def dataReceived(self, msg):
msg=self.in_buffer+msg
while msg is not None and len(msg)>=16:
pkt, msg = CAmessage.unpack(msg)
hdl = self._circ.get(pkt.cmd, self.server.dispatch)
hdl(pkt, self, self.peer)
self.in_buffer=msg # save remaining
def __str__(self):
return 'Circuit v4%(version)d to %(peer)s as %(host)s:%(user)s'% \
self.__dict__
def connectionFailed(self, reason):
C, self.__C = self.__C, DeferredManager()
C.callback(None)
def doCon(self):
self._D = DeferredManager()
self._C.callback(self)
def doFail(self):
d, self._C = self._C, DeferredManager()
d.callback(None)
def doLost(self):
self._C = DeferredManager()
d, self._D = self._D, DeferredManager()
class CASet(object):
"""Write to a PV
"""
def __init__(self,
channel,
data,
dbf=None,
meta=META.PLAIN,
dbf_conv=None,
wait=False):
"""Start a new write request
channel: PV name
data: value array
dbf: Field type to write
meta: Meta data class to send
dbf_conv: Treat value array as different field type.
Does a client-side conversion
wait: Request notification on completion
"""
self._chan, self.dbf = channel, dbf
self._data, self.dbf_conv = data, dbf_conv
self._meta, self._wait = meta, wait
self.done, self.ioid = True, None
self.__D = None
if dbf_conv is None and dbf is not None:
self.meta = caMeta(dbf)
elif dbf_conv is not None:
self.meta = caMeta(dbf_conv)
else:
self.meta = None
self.restart(data)
@property
def complete(self):
"""A Deferred called when the write has finished.
This is either when the request is sent, or when
confirmation is received depending on the type of
write.
"""
return self._comp.get()
def close(self):
"""Cancel the request
"""
if self._chan is None:
return # already shutdown
if not self.done and self._comp:
self._comp.callback(None)
if self.__D is not None and hasattr(self.__D, 'cancel'):
d, self.__D = self.__D, None
d.addErrback(lambda e: e.trap(CancelledError))
d.cancel()
self._chan = None
def restart(self, data):
"""Re-send with new value array
"""
if not self.done:
raise RuntimeError('Previous Set not complete')
self._data = data
self.done = False
self._comp = DeferredManager()
d = self.__D = self._chan.whenCon
d.addCallback(self._chanOk)
def _chanOk(self, chan):
self.__D = None
if chan is None:
self.close()
# channel has shutdown
return
assert self._chan is chan
self.ioid = chan._circ.pendingActions.add(self)
dbf = self.dbf
if dbf is None:
dbf, _ = dbr_to_dbf(chan.dbr)
dbr = dbf_to_dbr(dbf, self._meta)
meta = self.meta
if meta is None:
meta = caMeta(dbf)
data = self._data
cnt = len(data)
if cnt > chan.maxcount:
cnt = chan.maxcount
data = data[:chan.maxcount]
data, cnt = tostring(data, meta, dbr, cnt)
log.debug('Set %s to %s', chan, data)
cmd = 19 if self._wait else 4
msg = CAmessage(cmd=cmd,
size=len(data),
dtype=dbr,
count=cnt,
p1=chan.sid,
p2=self.ioid,
body=data).pack()
chan._circ.send(msg)
if not self._wait:
log.debug('Send put request (no wait) %s', self._chan.name)
# do completion here
self.ioid = None
self.done = True
self._comp.callback(ECA_NORMAL)
else:
log.debug('Send put request (wait) %s', self._chan.name)
d = self.__D = self._chan.whenDis
d.addCallback(self._circuitLost)
return chan
def _circuitLost(self, _):
self.__D = None
self.ioid = None
if self.done:
return
d = self.__D = self._chan.whenCon
d.addCallback(self._chanOk)
def dispatch(self, pkt, circuit, peer=None):
if pkt.cmd != 19:
log.warning('Channel %s get ignoring pkt %s', self._chan.name, pkt)
# wait for real reply
chan._circ.pendingActions[self.ioid] = self
return
self.ioid = None
self.done = True
# mark done so callback can restart
if pkt.p1 == ECA_NORMAL:
self._comp.callback(ECA_NORMAL)
else:
self._comp.errback(pkt.p1)
def __str__(self):
cnt = 'Native' if self.count is None else self.count
return 'Set %s of %s from %s' % (cnt, self.dbr, self._chan)
class CAClient(object):
"""Channel Access Client context
Manages name search requests and TCP connections.
"""
implements(IClient, IDispatch)
running = True
def __init__(self,
conf=Config.default,
user=None,
host=None,
reactor=reactor):
"""Construct a new client context
Prepare a new context with the given config.
If user and host are None then they are collected
from the environment.
"""
self.conf, self.reactor = conf, reactor
self.circuits = CACircuitFactory(self)
self.resolv = Resolver(self.circuits, conf)
self._onClose = DeferredManager()
if host is None:
from socket import gethostname
host = gethostname()
self.host = host
if user is None:
from getpass import getuser
user = getuser()
self.user = user
reactor.addSystemEventTrigger("before", "shutdown", self.close)
@property
def onClose(self):
return self._onClose.get()
def close(self):
"""Stop a client context.
This will close all circuits and fail any pending
actions (get, put, monitor, lookup)
Returns a Deferred which is called when shutdown is
complete
"""
if not self.running:
return
self.running = False
self.onClose.callback(self)
d = self.resolv.close()
self.circuits.close()
return d
def lookup(self, name):
"""Request a lookup on a PV name.
Returns a Deferred() which will be called with
a value which can be passed to openCircuit() or
None if a Name lookup is not possible.
Name lookups only fail when the client context
is closed.
"""
if not self.running:
return succeed(None)
return self.resolv.lookup(name)
def openCircuit(self, srv):
"""Request a circuit to the given CA server.
Returns a Deferred() which is called with an
instance of CAClientcircuit or None (failure).
This request fails if the circuit can not be
opened.
"""
if not self.running:
return succeed(None)
return self.circuits.requestCircuit(srv)
def dispatch(self, pkt, circuit, peer=None):
log.info('Client received unexpected from %s %s', peer, pkt)
class CAGet(object):
"""A non-recuring request for data
"""
implements(IDispatch)
done = True
ioid = None
__D = None
def __init__(self,
channel,
dbf=None,
count=None,
meta=META.PLAIN,
dbf_conv=None):
"""Start a new request.
channel: PV name
dbf: Field type requested from server
count: length requested from server
meta: Meta-data class requested
dbf_conv: Additional client side conversion
before data is returned to user.
Note: Server will never return more then count
elements, but may return less.
"""
self._chan, self.dbf = channel, dbf
self._meta, self.count = meta, count
self.dbf_conv = dbf_conv
if dbf_conv is None and dbf is not None:
self.meta = caMeta(dbf)
elif dbf_conv is not None:
self.meta = caMeta(dbf_conv)
else:
self.meta = None
self.restart()
def close(self):
"""Cancel request
"""
if self._chan is None:
return # already shutdown
if not self.done:
self._result.callback(None)
self.done = True
if self.ioid is not None and self._chan._circ is not None:
self._chan._circ.pendingActions.remove(self.ioid)
if self.__D is not None and hasattr(self.__D, 'cancel'):
self.__D.addErrback(lambda e: e.trap(CancelledError))
self.__D.cancel()
self.__D = None
self._chan = None
def restart(self):
"""Restart request
Send a new request to the server.
Note: A no-op if a request is currently in progress.
"""
if not self.done:
return
self.done = False
self._result = DeferredManager()
d = self.__D = self._chan.whenCon
d.addCallback(self._chanOk)
@property
def data(self):
"""A Deferred which will be called with the result
Will be called with a tuple (value array, caMeta)
"""
return self._result.get()
def _chanOk(self, chan):
self.__D = None
if chan is None:
# channel has shutdown
self.close()
return
assert self._chan is chan
ver = chan._circ.version
self.ioid = chan._circ.pendingActions.add(self)
dbf = self.dbf
if dbf is None:
dbf, _ = dbr_to_dbf(chan.dbr)
dbr = dbf_to_dbr(dbf, self._meta)
# use dynamic array length whenever possible
cnt = self.count if ver < 13 else 0
if cnt is None or cnt > chan.maxcount:
cnt = chan.maxcount
msg = CAmessage(cmd=15,
dtype=dbr,
count=cnt,
p1=chan.sid,
p2=self.ioid).pack()
chan._circ.send(msg)
d = self.__D = self._chan.whenDis
d.addCallback(self._circuitLost)
return chan
def _circuitLost(self, _):
self.__D = None
self.ioid = None
if self.done:
return
d = self._chan.eventCon
d.addCallback(self._chanOk)
def dispatch(self, pkt, circuit, peer=None):
if pkt.cmd != 15:
log.warning('Channel %s get ignoring pkt %s', self._chan.name, pkt)
# wait for real reply
chan._circ.pendingActions[self.ioid] = self
return
meta = self.meta
if meta is None:
dbf, _ = dbr_to_dbf(pkt.dtype)
meta = caMeta(dbf)
data = fromstring(pkt.body, pkt.dtype, pkt.count, meta)
self.ioid = None
self.done = True
self._result.callback(data)
def __str__(self):
cnt = 'Native' if self.count is None else self.count
return 'Get %s of %s from %s' % (cnt, self.dbr, self._chan)
def __init__(self):
self._C = DeferredManager()
self._D = DeferredManager()
self._D.callback(None)