def reconnect(self): # recreate a broken connection
"""reconnect() creates or recreates our main connection. Useful in __init__ and in complete communications breakdowns.
If it throws a VXI_11_Transient_Error, the connection exists, but the check_idn() handshake or post_init() failed."""
self.connected = 0
if self.core:
# if this is a reconnect, break old connection the hard way
self.core.close()
if self.abort_channel:
self.abort_channel.close()
self.core = rpc.TCPClient(self.host,
395183,
1,
portmap_proxy_host=self.portmap_proxy_host,
portmap_proxy_port=self.portmap_proxy_port)
self._core_packers, self._core_unpackers = self._link_xdr_defs(
self.core) # construct xdr data type definitions for the core
err, self.lid, self.abortPort, self.maxRecvSize = self.command(
10,
"create_link",
"create_link", (0, 0, self.timeout, self.device_sicl_name),
ignore_connect=1) # execute create_link
# at this stage, we always raise exceptions since there isn't any way to
# bail out or retry reasonably
if err:
raise VXI_11_Error(err)
# never transfer more than 1MB at a shot
self.maxRecvSize = min(self.maxRecvSize, 1048576)
if self.abortPort and self.OneWayAbort:
#self.abort_channel=OneWayAbortClient(self.host, 395184, 1, self.abortPort)
self.abort_channel = rpc.RawUDPClient(self.host, 395184, 1,
self.abortPort)
elif self.abortPort:
self.abort_channel = RawTCPClient(self.host, 395184, 1,
self.abortPort)
else:
self.abort_channel = None
connection_dict[self.lid] = (self.device_name, weakref.ref(self))
self.locklevel = 0
self.connected = 1
self.check_idn()
self.post_init()
def reconnect(self): # recreate a broken connection
"""reconnect() creates or recreates our main connection. Useful in __init__ and in complete communications breakdowns.
If it throws a VXI_11_Transient_Error, the connection exists, but the check_idn() handshake or post_init() failed."""
self.connected = 0
if self.core:
# if this is a reconnect, break old connection the hard way
self.core.close()
if self.abort_channel:
self.abort_channel.close()
self.core = rpc.TCPClient(self.host, 395183, 1,
portmap_proxy_host=self.portmap_proxy_host,
portmap_proxy_port=self.portmap_proxy_port)
self._core_packers, self._core_unpackers = self._link_xdr_defs(
self.core) # construct xdr data type definitions for the core
err, self.lid, self.abortPort, self.maxRecvSize = self.command(
10, "create_link", "create_link",
(0, 0, self.timeout, self.device_sicl_name),
ignore_connect=1) # execute create_link
# at this stage, we always raise exceptions since there isn't any way to
# bail out or retry reasonably
if err:
raise VXI_11_Error(err)
# never transfer more than 1MB at a shot
self.maxRecvSize = min(self.maxRecvSize, 1048576)
if self.abortPort and self.OneWayAbort:
#self.abort_channel=OneWayAbortClient(self.host, 395184, 1, self.abortPort)
self.abort_channel = rpc.RawUDPClient(
self.host, 395184, 1, self.abortPort)
elif self.abortPort:
self.abort_channel = RawTCPClient(self.host, 395184, 1, self.abortPort)
else:
self.abort_channel = None
connection_dict[self.lid] = (self.device_name, weakref.ref(self))
self.locklevel = 0
self.connected = 1
self.check_idn()
self.post_init()
def reconnect(self): #recreate a broken connection """reconnect() creates or recreates our main connection. Useful in __init__ and in complete communications breakdowns. If it throws a VXI_11_Transient_Error, the connection exists, but the check_idn() handshake or post_init() failed.""" self.connected=0 if self.core: self.core.close() #if this is a reconnect, break old connection the hard way if self.abortChannel: self.abortChannel.close() self.core=rpc.TCPClient(self.host, 395183, 1, portmap_proxy_host=self.portmap_proxy_host, portmap_proxy_port=self.portmap_proxy_port) self._core_packers, self._core_unpackers=self._link_xdr_defs(self.core) #construct xdr data type definitions for the core err, self.lid, self.abortPort, self.maxRecvSize=self.command( 10, "create_link","create_link", (0, 0, self.timeout, self.device_sicl_name), ignore_connect=1) #execute create_link if err: #at this stage, we always raise exceptions since there isn't any way to bail out or retry reasonably raise VXI_11_Error(err) self.maxRecvSize=min(self.maxRecvSize, 1048576) #never transfer more than 1MB at a shot if self.OneWayAbort: #self.abort_channel=OneWayAbortClient(self.host, 395184, 1, self.abortPort) self.abort_channel=rpc.RawUDPClient(self.host, 395184, 1, self.abortPort) else: self.abort_channel=RawTCPClient(self.host, 395184, 1, self.abortPort) connection_dict[self.lid]=(self.device_name, weakref.ref(self)) self.locklevel=0 self.connected=1 # Not doing this next line because we never know what we have for # connections until the database tells us it's what we are supposed # to have. We simply want to collect the information. #self.check_idn() # Here is where we collect the information from the GPIB instrument # (if there is one at this address). self.queryIDN() self.post_init()
class vxi_11_connection:
"""vxi_11_connection implements handling of devices compliant with vxi11.1-vxi11.3 protocols, with which
the user should have some familiarity"""
debug_info=0
debug_error=1
debug_warning=2
debug_all=3
debug_level=debug_error
OneWayAbort=0 #by default, this class uses two-way aborts, per official vxi-11 standard
def _list_packer(self, args):
l=map(None, self.pack_type_list, args) # combine lists
for packer, data in l:
packer(data)
def _list_unpacker(self):
return [func() for func in self.unpack_type_list]
def _link_xdr_defs(self, channel):
"self.link_xdr_defs() creates dictionaries of functions for packing and unpacking the various data types"
p=channel.packer
u=channel.unpacker
xdr_packer_defs={
"write": (p.pack_int, p.pack_int, p.pack_int, p.pack_int, p.pack_opaque),
"read": (p.pack_int, p.pack_int, p.pack_int, p.pack_int, p.pack_int, p.pack_int),
"create_link": (p.pack_int, p.pack_bool, p.pack_uint, p.pack_string),
"generic": (p.pack_int, p.pack_int, p.pack_int, p.pack_int),
"lock": (p.pack_int, p.pack_int, p.pack_int),
"id": (p.pack_int,)
}
xdr_unpacker_defs={
"write": (u.unpack_int, u.unpack_int),
"read": (u.unpack_int, u.unpack_int, u.unpack_opaque),
"create_link": (u.unpack_int, u.unpack_int, u.unpack_uint, u.unpack_uint),
"read_stb":(u.unpack_int, u.unpack_int),
"error": (u.unpack_int,)
}
return xdr_packer_defs, xdr_unpacker_defs
def _setup_core_packing(self, pack, unpack):
self.pack_type_list, self.unpack_type_list=self._core_packers[pack],self._core_unpackers[unpack]
def post_init(self):
pass
def simple_log_error(self, message, level=debug_error, file=None):
if level <= self.debug_level:
if file is None:
file=sys.stderr
print >> file, self.device_name, message
def fancy_log_error(self, message, level=debug_error, file=None):
if level <= self.debug_level:
message=str(message).strip()
level_str=("**INFO*****", "**ERROR****", "**WARNING**", "**DEBUG****")[level]
if file is None:
file=sys.stderr
print >> file, time.asctime().strip(), '\t', level_str, '\t', self.shortname, '\t', \
message.replace('\n','\n\t** ').replace('\r','\n\t** ')
def log_error(self, message, level=debug_error, file=None):
"override log_error() for sending messages to special places or formatting differently"
self.fancy_log_error(message, level, file)
def log_traceback(self, main_message='', file=None):
exlist=traceback.format_exception(*sys.exc_info())
s=main_message+'\n'
for i in exlist:
s=s+i
self.log_error(s, self.debug_error, file)
def log_info(self, message, file=None):
self.log_error(message, self.debug_info, file)
def log_warning(self, message, file=None):
self.log_error(message, self.debug_warning, file)
def log_debug(self, message, file=None):
self.log_error(message, self.debug_all, file)
def log_exception(self, main_message='', file=None):
self.log_error(main_message+traceback.format_exception_only(*(sys.exc_info()[:2]))[0], self.debug_error, file)
def __init__(self, host='127.0.0.1', device="inst0", timeout=1000, raise_on_err=None, device_name="Network Device", shortname=None,
portmap_proxy_host=None, portmap_proxy_port=rpc.PMAP_PORT):
self.raise_on_err=raise_on_err
self.lid=None
self.timeout=timeout
self.device_name=device_name
self.device_sicl_name=device
self.host=host
self.portmap_proxy_host=portmap_proxy_host
self.portmap_proxy_port=portmap_proxy_port
self.core=None
self.abortChannel=None
self.mux=None #default is no multiplexer active
if shortname is None:
self.shortname=device_name.strip().replace(' ','').replace('\t','')
else:
self.shortname=shortname.strip().replace(' ','').replace('\t','')
if threads:
self.threadlock=threading.RLock()
try:
self.reconnect()
except VXI_11_Transient_Error:
self.log_exception("Initial connect failed... retry later")
def setup_mux(self, mux=None, global_name=None):
self.mux=mux
self.global_mux_name=global_name
def command(self, id, pack, unpack, arglist, ignore_connect=0):
if not (ignore_connect or self.connected):
raise VXI_11_Device_Not_Connected
self._setup_core_packing(pack, unpack)
try:
result= self.core.make_call(id, arglist, self._list_packer, self._list_unpacker)
except (RuntimeError, EOFError):
#RuntimeError is thrown by recvfrag if the xid is off... it means we lost data in the pipe
#EOFError is thrown if the packet isn't full length, as usually happens when ther is garbage in the pipe read as a length
#so vacuum out the socket, and raise a transient error
rlist=1
ntotal=0
while(rlist):
rlist, wlist, xlist=select.select([self.core.sock],[],[], 1.0)
if rlist:
ntotal+=len(self.core.sock.recv(10000) )#get some data from it
raise VXI_11_Stream_Sync_Lost("sync", ntotal)
err=result[0]
if err and self.raise_on_err:
e=_VXI_11_enumerated_exceptions #common, correctable exceptions
if e.has_key(err):
raise e[err](err) #raise these exceptions explicitly
else:
raise VXI_11_Error(err) #raise generic VXI_11 exception
return result
def do_timeouts(self, timeout, lock_timeout, channel=None):
if channel is None:
channel=self.core
flags=0
if timeout is None:
timeout=self.timeout
if not lock_timeout and hasattr(self,"default_lock_timeout"):
lock_timeout=self.default_lock_timeout
if lock_timeout:
flags |= 1 # append waitlock bit
if channel:
channel.select_timeout_seconds=1.5*max(timeout, lock_timeout)/1000.0 #convert ms to sec, and be generous on hard timeout
return flags, timeout, lock_timeout
def reconnect(self): #recreate a broken connection
"""reconnect() creates or recreates our main connection. Useful in __init__ and in complete communications breakdowns.
If it throws a VXI_11_Transient_Error, the connection exists, but the check_idn() handshake or post_init() failed."""
self.connected=0
if self.core:
self.core.close() #if this is a reconnect, break old connection the hard way
if self.abortChannel:
self.abortChannel.close()
self.core=rpc.TCPClient(self.host, 395183, 1,
portmap_proxy_host=self.portmap_proxy_host,
portmap_proxy_port=self.portmap_proxy_port)
self._core_packers, self._core_unpackers=self._link_xdr_defs(self.core) #construct xdr data type definitions for the core
err, self.lid, self.abortPort, self.maxRecvSize=self.command(
10, "create_link","create_link", (0, 0, self.timeout, self.device_sicl_name), ignore_connect=1) #execute create_link
if err: #at this stage, we always raise exceptions since there isn't any way to bail out or retry reasonably
raise VXI_11_Error(err)
self.maxRecvSize=min(self.maxRecvSize, 1048576) #never transfer more than 1MB at a shot
if self.OneWayAbort:
#self.abort_channel=OneWayAbortClient(self.host, 395184, 1, self.abortPort)
self.abort_channel=rpc.RawUDPClient(self.host, 395184, 1, self.abortPort)
else:
self.abort_channel=RawTCPClient(self.host, 395184, 1, self.abortPort)
connection_dict[self.lid]=(self.device_name, weakref.ref(self))
self.locklevel=0
self.connected=1
self.check_idn()
self.post_init()
def abort(self):
self.abort_channel.select_timeout_seconds=self.timeout/1000.0 #convert to seconds
try:
err=self.abort_channel.make_call(1, self.lid, self.abort_channel.packer.pack_int, self.abort_channel.unpacker.unpack_int) #abort
except EOFError:
raise VXI_11_RPC_EOF("eof")
if err and self.raise_on_err:
raise VXI_11_Error( err)
return err
def disconnect(self):
if self.connected:
try:
err, =self.command(23, "id", "error", (self.lid,)) #execute destroy_link
except:
self.log_traceback() #if we can't close nicely, we'll close anyway
self.connected=0
del connection_dict[self.lid]
self.lid=None
self.core.close()
self.abort_channel.close()
del self.core, self.abort_channel
self.core=None
self.abortChannel=None
def __del__(self):
if self.lid is not None:
self.raise_on_err=0 #no exceptions here from simple errors
try:
self.abort()
except VXI_11_Error:
pass
try:
self.disconnect()
except VXI_11_Error:
pass
def write(self, data, timeout=None, lock_timeout=0):
"""err, bytes_sent=write(data [, timeout] [,lock_timeout]) sends data to device. See do_timeouts() for
semantics of timeout and lock_timeout"""
flags, timeout, lock_timeout=self.do_timeouts(timeout, lock_timeout)
base=0
end=len(data)
while base<end:
n=end-base
if n>self.maxRecvSize:
xfer=self.maxRecvSize
else:
xfer=n
flags |= 8 #write end on last byte
err, count=self.command(11, "write", "write", (self.lid, timeout, lock_timeout, flags, data[base:base+xfer]))
if err: break
base+=count
return err, base
def read(self, timeout=None, lock_timeout=0, count=None, termChar=None):
"""err, reason, result=read([timeout] [,lock_timeout] [,count] [,termChar]) reads up to count bytes from the device,
ending on count, EOI or termChar (if specified). See do_timeouts() for semantics of the timeouts. \n
the returned reason is an inclusive OR of 3 bits (per the VXI-11 specs section B.6.4.device_read):
Bit 2 = END/EOI received,
bit 1 = Terminating Character received,
bit 0 = full requested byte count received.
"""
flags, timeout, lock_timeout=self.do_timeouts(timeout, lock_timeout)
if termChar is not None:
flags |= 128 # append termchrset bit
act_term=termChar
else:
act_term=0
accumdata=""
reason=0
err=0
accumlen=0
while ( (not err) and (not (reason & 4) ) and
( (count is None) or (accumlen < count)) and
( (termChar is None) or (accumdata[-1] != termChar)) ): #wait for END flag or count or matching terminator char
readcount=self.maxRecvSize/2
if count is not None:
readcount=min(readcount, count-accumlen)
err, reason, data = self.command(12, "read","read", (self.lid, readcount, timeout, lock_timeout, flags, act_term))
accumdata+=data
accumlen+=len(data)
#print err, reason, len(data), len(accumdata)
return err, reason, accumdata
def generic(self, code, timeout, lock_timeout):
flags, timeout, lock_timeout=self.do_timeouts(timeout, lock_timeout)
err, = self.command(code, "generic", "error", (self.lid, flags, timeout, lock_timeout))
return err
def trigger(self, timeout=None, lock_timeout=0):
return self.generic(14, timeout, lock_timeout)
def clear(self, timeout=None, lock_timeout=0):
return self.generic(15, timeout, lock_timeout)
def remote(self, timeout=None, lock_timeout=0):
return self.generic(16, timeout, lock_timeout)
def local(self, timeout=None, lock_timeout=0):
return self.generic(17, timeout, lock_timeout)
def read_status_byte(self, timeout=None, lock_timeout=0):
flags, timeout, lock_timeout=self.do_timeouts(timeout, lock_timeout)
err, status = self.command(13, "generic","read_stb", (self.lid, flags, timeout, lock_timeout))
return err, status
def lock(self, lock_timeout=0):
"lock() acquires a lock on a device and the threadlock. If it fails it leaves the connection cleanly unlocked"
err=0
if threads:
self.threadlock.acquire()
if self.locklevel==0:
flags, timeout, lock_timeout=self.do_timeouts(0, lock_timeout)
try:
if self.mux: self.mux.lock_connection(self.global_mux_name)
try:
err, = self.command(18, "lock","error", (self.lid, flags, lock_timeout))
except:
if self.mux: self.mux.unlock_connection(self.global_mux_name)
raise
except:
if threads:
self.threadlock.release()
raise
if err:
if threads:
self.threadlock.release()
else:
self.locklevel+=1
return err
def is_locked(self):
return self.locklevel > 0
def unlock(self, priority=0):
"""unlock(priority=0) unwinds one level of locking, and if the level is zero, really unlocks the device.
Calls to lock() and unlock() should be matched. If there is a danger that they are not, due to bad
exception handling, unlock_completely() should be used as a final cleanup for a series of operations.
Setting priority to non-zero will bias the apparent last-used time in a multiplexer (if one is used),
so setting priority to -10 will effectively mark this channel least-recently-used, while setting it to
+2 will post-date the last-used time 2 seconds, so for the next 2 seconds, the device will be hard to kick
out of the channel cache (but not impossible).
"""
self.locklevel-=1
assert self.locklevel>=0, "Too many unlocks on device: "+self.device_name
err=0
try:
if self.locklevel==0:
try:
err, = self.command(19, "id", "error", (self.lid, ))
finally:
if self.mux:
self.mux.unlock_connection(self.global_mux_name, priority) #this cannot fail, no try needed (??)
elif priority and self.mux:
#even on a non-final unlock, a request for changed priority is always remembered
self.mux.adjust_priority(self.global_mux_name, priority)
finally:
if threads:
self.threadlock.release()
return err
def unlock_completely(self, priority=0):
"unlock_completely() forces an unwind of any locks all the way back to zero for error cleanup. Only exceptions thrown are fatal."
if threads:
self.threadlock.acquire() #make sure we have the threadlock before we try a (possibly failing) full lock
try:
self.lock() #just to be safe, we should already hold one level of lock!
except VXI_11_Locked_Elsewhere:
pass #this is often called on error cleanup when we don't already have a lock, and we don't really care if we can't get it
except VXI_11_Error:
self.log_exception("Unexpected trouble locking in unlock_completely(): ")
if threads:
self.threadlock._RLock__count += (1-self.threadlock._RLock__count)
#unwind to single lock the fast way, and make sure this variable really existed, to shield against internal changes
self.locklevel=1 #unwind our own counter, too
try:
self.unlock(priority)
except VXI_11_Device_Not_Locked:
pass #if we couldn't lock above, we will probably get another exception here, and don't care
except VXI_11_Transient_Error:
self.log_exception("Unexpected trouble unlocking in unlock_completely(): ")
except VXI_11_Error:
self.log_exception("Unexpected trouble unlocking in unlock_completely(): ")
raise
def transaction(self, data, count=None, lock_timeout=0):
"""err, reason, result=transaction(data, [, count] [,lock_timeout]) sends data and waits for a response.
It is guaranteed to leave the lock level at its original value on exit,
unless KeyboardInterrupt breaks the normal flow. If count isn't provided, there is no limit to how much data will be accepted.
See do_timeouts() for semantics on lock_timeout."""
self.lock(lock_timeout)
reason=None
result=None
try:
err, write_count = self.write(data)
if not err:
err, reason, result = self.read(count=count)
finally:
self.unlock()
return err, reason, result
def check_idn(self):
'check_idn() executes "*idn?" and aborts if the result does not start with self.idn_head'
if hasattr(self,"idn"):
return #already done
if hasattr(self,"idn_head") and self.idn_head is not None:
self.lock()
try:
self.clear()
err, reason, idn = self.transaction("*idn?")
print err, reason, idn
finally:
self.unlock()
check=idn.find(self.idn_head)
self.idn=idn.strip() #save for future reference info
if check:
self.disconnect()
assert check==0, "Wrong device type! expecting: "+self.idn_head+"... got: "+self.idn
else:
self.idn="Device *idn? not checked!"
class vxi_11_connection:
"""vxi_11_connection implements handling of devices compliant with vxi11.1-vxi11.3 protocols, with which
the user should have some familiarity"""
debug_info = 0
debug_error = 1
debug_warning = 2
debug_all = 3
debug_level = debug_error
OneWayAbort = 0 #by default, this class uses two-way aborts, per official vxi-11 standard
def _list_packer(self, args):
l = map(None, self.pack_type_list, args) # combine lists
for packer, data in l:
packer(data)
def _list_unpacker(self):
return [func() for func in self.unpack_type_list]
def _link_xdr_defs(self, channel):
"self.link_xdr_defs() creates dictionaries of functions for packing and unpacking the various data types"
p = channel.packer
u = channel.unpacker
xdr_packer_defs = {
"write":
(p.pack_int, p.pack_int, p.pack_int, p.pack_int, p.pack_opaque),
"read": (p.pack_int, p.pack_int, p.pack_int, p.pack_int,
p.pack_int, p.pack_int),
"create_link":
(p.pack_int, p.pack_bool, p.pack_uint, p.pack_string),
"generic": (p.pack_int, p.pack_int, p.pack_int, p.pack_int),
"lock": (p.pack_int, p.pack_int, p.pack_int),
"id": (p.pack_int, )
}
xdr_unpacker_defs = {
"write": (u.unpack_int, u.unpack_int),
"read": (u.unpack_int, u.unpack_int, u.unpack_opaque),
"create_link":
(u.unpack_int, u.unpack_int, u.unpack_uint, u.unpack_uint),
"read_stb": (u.unpack_int, u.unpack_int),
"error": (u.unpack_int, )
}
return xdr_packer_defs, xdr_unpacker_defs
def _setup_core_packing(self, pack, unpack):
self.pack_type_list, self.unpack_type_list = self._core_packers[
pack], self._core_unpackers[unpack]
def post_init(self):
pass
def simple_log_error(self, message, level=debug_error, file=None):
if level <= self.debug_level:
if file is None:
file = sys.stderr
print >> file, self.device_name, message
def fancy_log_error(self, message, level=debug_error, file=None):
if level <= self.debug_level:
message = str(message).strip()
level_str = ("**INFO*****", "**ERROR****", "**WARNING**",
"**DEBUG****")[level]
if file is None:
file = sys.stderr
print >> file, time.asctime().strip(), '\t', level_str, '\t', self.shortname, '\t', \
message.replace('\n','\n\t** ').replace('\r','\n\t** ')
def log_error(self, message, level=debug_error, file=None):
"override log_error() for sending messages to special places or formatting differently"
self.fancy_log_error(message, level, file)
def log_traceback(self, main_message='', file=None):
exlist = traceback.format_exception(*sys.exc_info())
s = main_message + '\n'
for i in exlist:
s = s + i
self.log_error(s, self.debug_error, file)
def log_info(self, message, file=None):
self.log_error(message, self.debug_info, file)
def log_warning(self, message, file=None):
self.log_error(message, self.debug_warning, file)
def log_debug(self, message, file=None):
self.log_error(message, self.debug_all, file)
def log_exception(self, main_message='', file=None):
self.log_error(
main_message +
traceback.format_exception_only(*(sys.exc_info()[:2]))[0],
self.debug_error, file)
def __init__(self,
host='127.0.0.1',
device="inst0",
timeout=1000,
raise_on_err=None,
device_name="Network Device",
shortname=None,
portmap_proxy_host=None,
portmap_proxy_port=rpc.PMAP_PORT,
use_vxi_locking=True):
self.raise_on_err = raise_on_err
self.lid = None
self.timeout = timeout
self.device_name = device_name
self.device_sicl_name = device
self.host = host
self.portmap_proxy_host = portmap_proxy_host
self.portmap_proxy_port = portmap_proxy_port
self.core = None
self.abortChannel = None
self.mux = None #default is no multiplexer active
self.use_vxi_locking = use_vxi_locking
if shortname is None:
self.shortname = device_name.strip().replace(' ',
'').replace('\t', '')
else:
self.shortname = shortname.strip().replace(' ',
'').replace('\t', '')
if threads:
self.threadlock = threading.RLock()
try:
self.reconnect()
except VXI_11_Transient_Error:
self.log_exception("Initial connect failed... retry later")
def setup_mux(self, mux=None, global_name=None):
self.mux = mux
self.global_mux_name = global_name
def command(self, id, pack, unpack, arglist, ignore_connect=0):
if not (ignore_connect or self.connected):
raise VXI_11_Device_Not_Connected
#command has been made atomic, so that things like get_status_byte can be done
#in a multi-threaded environment without needed a full vxi-11 lock to make it safe
if threads:
self.threadlock.acquire() #make this atomic
self._setup_core_packing(pack, unpack)
try:
try:
result = self.core.make_call(id, arglist, self._list_packer,
self._list_unpacker)
except (RuntimeError, EOFError):
#RuntimeError is thrown by recvfrag if the xid is off... it means we lost data in the pipe
#EOFError is thrown if the packet isn't full length, as usually happens when ther is garbage in the pipe read as a length
#so vacuum out the socket, and raise a transient error
rlist = 1
ntotal = 0
while (rlist):
rlist, wlist, xlist = select.select([self.core.sock], [],
[], 1.0)
if rlist:
ntotal += len(
self.core.sock.recv(10000)) #get some data from it
raise VXI_11_Stream_Sync_Lost("sync", ntotal)
finally:
if threads:
self.threadlock.release() #let go
err = result[0]
if err and self.raise_on_err:
e = _VXI_11_enumerated_exceptions #common, correctable exceptions
if e.has_key(err):
raise e[err](err) #raise these exceptions explicitly
else:
raise VXI_11_Error(err) #raise generic VXI_11 exception
return result
def do_timeouts(self, timeout, lock_timeout, channel=None):
if channel is None:
channel = self.core
flags = 0
if timeout is None:
timeout = self.timeout
if not lock_timeout and hasattr(self, "default_lock_timeout"):
lock_timeout = self.default_lock_timeout
if lock_timeout:
flags |= 1 # append waitlock bit
if channel:
channel.select_timeout_seconds = 0.5 + 1.5 * max(
timeout, lock_timeout
) / 1000.0 #convert ms to sec, and be generous on hard timeout
return flags, timeout, lock_timeout
def reconnect(self): #recreate a broken connection
"""reconnect() creates or recreates our main connection. Useful in __init__ and in complete communications breakdowns.
If it throws a VXI_11_Transient_Error, the connection exists, but the check_idn() handshake or post_init() failed."""
self.connected = 0
if self.core:
self.core.close(
) #if this is a reconnect, break old connection the hard way
if self.abortChannel:
self.abortChannel.close()
self.core = rpc.TCPClient(self.host,
395183,
1,
portmap_proxy_host=self.portmap_proxy_host,
portmap_proxy_port=self.portmap_proxy_port)
self._core_packers, self._core_unpackers = self._link_xdr_defs(
self.core) #construct xdr data type definitions for the core
err, self.lid, self.abortPort, self.maxRecvSize = self.command(
10,
"create_link",
"create_link", (0, 0, self.timeout, self.device_sicl_name),
ignore_connect=1) #execute create_link
if err: #at this stage, we always raise exceptions since there isn't any way to bail out or retry reasonably
raise VXI_11_Error(err)
self.maxRecvSize = min(
self.maxRecvSize, 1048576) #never transfer more than 1MB at a shot
if self.OneWayAbort:
#self.abort_channel=OneWayAbortClient(self.host, 395184, 1, self.abortPort)
self.abort_channel = rpc.RawUDPClient(self.host, 395184, 1,
self.abortPort)
else:
self.abort_channel = RawTCPClient(self.host, 395184, 1,
self.abortPort)
connection_dict[self.lid] = (self.device_name, weakref.ref(self))
self.locklevel = 0
self.connected = 1
self.check_idn()
self.post_init()
def abort(self):
self.abort_channel.select_timeout_seconds = self.timeout / 1000.0 #convert to seconds
try:
err = self.abort_channel.make_call(
1, self.lid, self.abort_channel.packer.pack_int,
self.abort_channel.unpacker.unpack_int) #abort
except EOFError:
raise VXI_11_RPC_EOF("eof")
if err and self.raise_on_err:
raise VXI_11_Error(err)
return err
def disconnect(self):
if self.connected:
try:
err, = self.command(23, "id", "error",
(self.lid, )) #execute destroy_link
except:
self.log_traceback(
) #if we can't close nicely, we'll close anyway
self.connected = 0
del connection_dict[self.lid]
self.lid = None
self.core.close()
self.abort_channel.close()
del self.core, self.abort_channel
self.core = None
self.abortChannel = None
def __del__(self):
if self.lid is not None:
self.raise_on_err = 0 #no exceptions here from simple errors
try:
self.abort()
except VXI_11_Error:
pass
try:
self.disconnect()
except VXI_11_Error:
pass
def write(self, data, timeout=None, lock_timeout=0):
"""err, bytes_sent=write(data [, timeout] [,lock_timeout]) sends data to device. See do_timeouts() for
semantics of timeout and lock_timeout"""
flags, timeout, lock_timeout = self.do_timeouts(timeout, lock_timeout)
base = 0
end = len(data)
while base < end:
n = end - base
if n > self.maxRecvSize:
xfer = self.maxRecvSize
else:
xfer = n
flags |= 8 #write end on last byte
err, count = self.command(11, "write", "write",
(self.lid, timeout, lock_timeout, flags,
data[base:base + xfer]))
if err: break
base += count
return err, base
def read(self, timeout=None, lock_timeout=0, count=None, termChar=None):
"""err, reason, result=read([timeout] [,lock_timeout] [,count] [,termChar]) reads up to count bytes from the device,
ending on count, EOI or termChar (if specified). See do_timeouts() for semantics of the timeouts. \n
the returned reason is an inclusive OR of 3 bits (per the VXI-11 specs section B.6.4.device_read):
Bit 2 = END/EOI received,
bit 1 = Terminating Character received,
bit 0 = full requested byte count received.
"""
flags, timeout, lock_timeout = self.do_timeouts(timeout, lock_timeout)
if termChar is not None:
flags |= 128 # append termchrset bit
act_term = termChar
else:
act_term = 0
accumdata = ""
reason = 0
err = 0
accumlen = 0
while ((not err) and (not (reason & 6)) and (
(count is None) or
(accumlen < count))): #wait for END or CHR reason flag or count
readcount = self.maxRecvSize
if count is not None:
readcount = min(readcount, count - accumlen)
err, reason, data = self.command(
12, "read", "read",
(self.lid, readcount, timeout, lock_timeout, flags, act_term))
accumdata += data
accumlen += len(data)
#print err, reason, len(data), len(accumdata)
return err, reason, accumdata
def generic(self, code, timeout, lock_timeout):
flags, timeout, lock_timeout = self.do_timeouts(timeout, lock_timeout)
err, = self.command(code, "generic", "error",
(self.lid, flags, timeout, lock_timeout))
return err
def trigger(self, timeout=None, lock_timeout=0):
return self.generic(14, timeout, lock_timeout)
def clear(self, timeout=None, lock_timeout=0):
return self.generic(15, timeout, lock_timeout)
def remote(self, timeout=None, lock_timeout=0):
return self.generic(16, timeout, lock_timeout)
def local(self, timeout=None, lock_timeout=0):
return self.generic(17, timeout, lock_timeout)
def read_status_byte(self, timeout=None, lock_timeout=0):
flags, timeout, lock_timeout = self.do_timeouts(timeout, lock_timeout)
err, status = self.command(13, "generic", "read_stb",
(self.lid, flags, timeout, lock_timeout))
return err, status
def lock(self, lock_timeout=0):
"""lock() acquires a lock on a device and the threadlock. If it fails it leaves the connection cleanly unlocked.
If self.use_vxi_locking is false, it acquires only a thread lock locally, and does not really lock the vxi-11 device.
This is useful if only one process is talking to a given device, and saves time."""
err = 0
if threads:
self.threadlock.acquire()
if self.use_vxi_locking and self.locklevel == 0:
flags, timeout, lock_timeout = self.do_timeouts(0, lock_timeout)
try:
if self.mux: self.mux.lock_connection(self.global_mux_name)
try:
err, = self.command(18, "lock", "error",
(self.lid, flags, lock_timeout))
except:
if self.mux:
self.mux.unlock_connection(self.global_mux_name)
raise
except:
if threads:
self.threadlock.release()
raise
if err:
if threads:
self.threadlock.release()
else:
self.locklevel += 1
return err
def is_locked(self):
return self.locklevel > 0
def unlock(self, priority=0):
"""unlock(priority=0) unwinds one level of locking, and if the level is zero, really unlocks the device.
Calls to lock() and unlock() should be matched. If there is a danger that they are not, due to bad
exception handling, unlock_completely() should be used as a final cleanup for a series of operations.
Setting priority to non-zero will bias the apparent last-used time in a multiplexer (if one is used),
so setting priority to -10 will effectively mark this channel least-recently-used, while setting it to
+2 will post-date the last-used time 2 seconds, so for the next 2 seconds, the device will be hard to kick
out of the channel cache (but not impossible).
"""
self.locklevel -= 1
assert self.locklevel >= 0, "Too many unlocks on device: " + self.device_name
err = 0
try:
if self.use_vxi_locking and self.locklevel == 0:
try:
err, = self.command(19, "id", "error", (self.lid, ))
finally:
if self.mux:
self.mux.unlock_connection(
self.global_mux_name,
priority) #this cannot fail, no try needed (??)
elif priority and self.mux:
#even on a non-final unlock, a request for changed priority is always remembered
self.mux.adjust_priority(self.global_mux_name, priority)
finally:
if threads:
self.threadlock.release()
return err
def unlock_completely(self, priority=0):
"unlock_completely() forces an unwind of any locks all the way back to zero for error cleanup. Only exceptions thrown are fatal."
if threads:
self.threadlock.acquire(
) #make sure we have the threadlock before we try a (possibly failing) full lock
try:
self.lock(
) #just to be safe, we should already hold one level of lock!
except VXI_11_Locked_Elsewhere:
pass #this is often called on error cleanup when we don't already have a lock, and we don't really care if we can't get it
except VXI_11_Error:
self.log_exception(
"Unexpected trouble locking in unlock_completely(): ")
if threads:
self.threadlock._RLock__count += (1 -
self.threadlock._RLock__count)
#unwind to single lock the fast way, and make sure this variable really existed, to shield against internal changes
self.locklevel = 1 #unwind our own counter, too
try:
self.unlock(priority)
except VXI_11_Device_Not_Locked:
pass #if we couldn't lock above, we will probably get another exception here, and don't care
except VXI_11_Transient_Error:
self.log_exception(
"Unexpected trouble unlocking in unlock_completely(): ")
except VXI_11_Error:
self.log_exception(
"Unexpected trouble unlocking in unlock_completely(): ")
raise
def transaction(self, data, count=None, lock_timeout=0):
"""err, reason, result=transaction(data, [, count] [,lock_timeout]) sends data and waits for a response.
It is guaranteed to leave the lock level at its original value on exit,
unless KeyboardInterrupt breaks the normal flow. If count isn't provided, there is no limit to how much data will be accepted.
See do_timeouts() for semantics on lock_timeout."""
self.lock(lock_timeout)
reason = None
result = None
try:
err, write_count = self.write(data)
if not err:
err, reason, result = self.read(count=count)
finally:
self.unlock()
return err, reason, result
def check_idn(self):
'check_idn() executes "*idn?" and aborts if the result does not start with self.idn_head'
if hasattr(self, "idn"):
return #already done
if hasattr(self, "idn_head") and self.idn_head is not None:
self.lock()
try:
self.clear()
err, reason, idn = self.transaction("*idn?")
finally:
self.unlock()
check = idn.find(self.idn_head)
self.idn = idn.strip() #save for future reference info
if check:
self.disconnect()
assert check == 0, "Wrong device type! expecting: " + self.idn_head + "... got: " + self.idn
else:
self.idn = "Device *idn? not checked!"
