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improve error handling on callbacks

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errors in callback functions should be reported to log,
but not stop the callback chain

Change-Id: I4fc509b7121960ebe59e1ad4f4b4746dfb4d5ba3
Reviewed-on: https://forge.frm2.tum.de/review/c/secop/frappy/+/30950
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>
This commit is contained in:
zolliker
2023-04-13 16:00:10 +02:00
parent 827d27ed59
commit ea5cdbbe44
2 changed files with 47 additions and 42 deletions
Download Patch File Download Diff File Expand all files Collapse all files

86
frappy/client/__init__.py
View File

@ -46,10 +46,10 @@ UPDATE_MESSAGES = {EVENTREPLY, READREPLY, WRITEREPLY, ERRORPREFIX + READREQUEST,
VERSIONFMT= re.compile(r'^[^,]*?ISSE[^,]*,SECoP,')
class UNREGISTER:
"""a magic value, used a returned value in a callback
to indicate it has to be unregistered
class UnregisterCallback(Exception):
"""raise in a callback to indicate it has to be unregistered
used to implement one shot callbacks
"""
@ -157,8 +157,8 @@ class CacheItem(tuple):
class ProxyClient:
"""common functionality for proxy clients"""
CALLBACK_NAMES = ('updateEvent', 'updateItem', 'descriptiveDataChange',
'nodeStateChange', 'unhandledMessage')
CALLBACK_NAMES = {'updateEvent', 'updateItem', 'descriptiveDataChange',
'nodeStateChange', 'unhandledMessage'}
online = False # connected or reconnecting since a short time
state = 'disconnected' # further possible values: 'connecting', 'reconnecting', 'connected'
log = None
@ -181,42 +181,41 @@ class ProxyClient:
"""
for cbfunc in args:
kwds[cbfunc.__name__] = cbfunc
for cbname in self.CALLBACK_NAMES:
cbfunc = kwds.pop(cbname, None)
if not cbfunc:
continue
cbdict = self.callbacks[cbname]
cbdict[key].append(cbfunc)
for cbname, cbfunc in kwds.items():
if cbname not in self.CALLBACK_NAMES:
raise TypeError(f"unknown callback: {', '.join(kwds)}")
# immediately call for some callback types
if cbname == 'updateItem':
if key is None:
for (mname, pname), data in self.cache.items():
cbfunc(mname, pname, data)
if cbname in ('updateItem', 'updateEvent'):
if key is None: # case generic callback
cbargs = [(m, p, d) for (m, p), d in self.cache.items()]
else:
data = self.cache.get(key, None)
if data:
cbfunc(*key, data) # case single parameter
if data: # case single parameter
cbargs = [key + (data,)]
else: # case key = module
for (mname, pname), data in self.cache.items():
if mname == key:
cbfunc(mname, pname, data)
elif cbname == 'updateEvent':
if key is None:
for (mname, pname), data in self.cache.items():
cbfunc(mname, pname, *data)
else:
data = self.cache.get(key, None)
if data:
cbfunc(*key, *data) # case single parameter
else: # case key = module
for (mname, pname), data in self.cache.items():
if mname == key:
cbfunc(mname, pname, *data)
cbargs = [(m, p, d) for (m, p), d in self.cache.items() if m == key]
if cbname == 'updateEvent':
# expand entry argument to (value, timestamp, readerror)
cbargs = [a[0:2] + a[2] for a in cbargs]
elif cbname == 'nodeStateChange':
cbfunc(self.online, self.state)
if kwds:
raise TypeError(f"unknown callback: {', '.join(kwds)}")
cbargs = [(self.online, self.state)]
else:
cbargs = []
do_append = True
for args in cbargs:
try:
cbfunc(*args)
except UnregisterCallback:
do_append = False
except Exception as e:
if self.log:
self.log.error('error %r calling %s%r', e, cbfunc.__name__, args)
if do_append:
self.callbacks[cbname][key].append(cbfunc)
def unregister_callback(self, key, *args, **kwds):
"""unregister a callback
@ -240,20 +239,27 @@ class ProxyClient:
key=(<module name>, <parameter name): callbacks for specified parameter
"""
cblist = self.callbacks[cbname].get(key, [])
self.callbacks[cbname][key] = [cb for cb in cblist if cb(*args) is not UNREGISTER]
for cbfunc in list(cblist):
try:
cbfunc(*args)
except UnregisterCallback:
cblist.remove(cbfunc)
except Exception as e:
if self.log:
self.log.error('error %r calling %s%r', e, cbfunc.__name__, args)
return bool(cblist)
def updateValue(self, module, param, value, timestamp, readerror):
entry = CacheItem(value, timestamp, readerror,
self.modules[module]['parameters'][param]['datatype'])
self.modules[module]['parameters'][param]['datatype'])
self.cache[(module, param)] = entry
self.callback(None, 'updateItem', module, param, entry)
self.callback(module, 'updateItem', module, param, entry)
self.callback((module, param), 'updateItem', module, param, entry)
# TODO: change clients to use updateItem instead of updateEvent
self.callback(None, 'updateEvent', module, param, value, timestamp, readerror)
self.callback(module, 'updateEvent', module, param, value, timestamp, readerror)
self.callback((module, param), 'updateEvent', module, param, value, timestamp, readerror)
self.callback(None, 'updateEvent', module, param, *entry)
self.callback(module, 'updateEvent', module, param, *entry)
self.callback((module, param), 'updateEvent', module, param, *entry)
class SecopClient(ProxyClient):

3
frappy/protocol/router.py
View File

@ -122,8 +122,7 @@ class Router(frappy.protocol.dispatcher.Dispatcher):
self.node_by_module[module] = node
self.nodes.append(node)
self.restart()
return frappy.client.UNREGISTER
return None
raise frappy.client.UnregisterCallback()
node.register_callback(None, nodeStateChange)
logger.warning('can not connect to node %r', node.nodename)