async def _connect(self, endpoints):
if len(endpoints) == 0:
raise errors.JujuConnectionError('no endpoints to connect to')
async def _try_endpoint(endpoint, cacert, delay):
if delay:
await asyncio.sleep(delay)
return await self._open(endpoint, cacert)
# Try all endpoints in parallel, with slight increasing delay (+100ms
# for each subsequent endpoint); the delay allows us to prefer the
# earlier endpoints over the latter. Use first successful connection.
tasks = [
self.loop.create_task(_try_endpoint(endpoint, cacert, 0.1 * i))
for i, (endpoint, cacert) in enumerate(endpoints)
]
for task in asyncio.as_completed(tasks, loop=self.loop):
try:
result = await task
break
except ConnectionError:
continue # ignore; try another endpoint
else:
raise errors.JujuConnectionError(
'Unable to connect to any endpoint: {}'.format(', '.join(
[endpoint for endpoint, cacert in endpoints])))
for task in tasks:
task.cancel()
self.ws = result[0]
self.addr = result[1]
self.endpoint = result[2]
self.cacert = result[3]
self._receiver_task.start()
log.info("Driver connected to juju %s", self.addr)
self.monitor.close_called.clear()
async def _connect(self, endpoints):
if len(endpoints) == 0:
raise errors.JujuConnectionError('no endpoints to connect to')
async def _try_endpoint(endpoint, cacert, delay):
if delay:
await asyncio.sleep(delay)
return await self._open(endpoint, cacert)
# Try all endpoints in parallel, with slight increasing delay (+100ms
# for each subsequent endpoint); the delay allows us to prefer the
# earlier endpoints over the latter. Use first successful connection.
tasks = [
self.loop.create_task(_try_endpoint(endpoint, cacert, 0.1 * i))
for i, (endpoint, cacert) in enumerate(endpoints)
]
for attempt in range(self._retries + 1):
for task in asyncio.as_completed(tasks, loop=self.loop):
try:
result = await task
break
except ConnectionError:
continue # ignore; try another endpoint
else:
_endpoints_str = ', '.join(
[endpoint for endpoint, cacert in endpoints])
if attempt < self._retries:
log.debug('Retrying connection to endpoints: {}; '
'attempt {} of {}'.format(
_endpoints_str, attempt + 1,
self._retries + 1))
await asyncio.sleep((attempt + 1) * self._retry_backoff)
continue
else:
raise errors.JujuConnectionError(
'Unable to connect to any endpoint: '
'{}'.format(_endpoints_str))
# only executed if inner loop's else did not continue
# (i.e., inner loop did break due to successful connection)
break
for task in tasks:
task.cancel()
self.ws = result[0]
self.addr = result[1]
self.endpoint = result[2]
self.cacert = result[3]
self._receiver_task.start()
log.debug("Driver connected to juju %s", self.addr)
self.monitor.close_called.clear()
def _build_facades(self, facades):
self.facades.clear()
for facade in facades:
name = facade['name']
# the following attempts to get the best facade version for the
# client. The client knows about the best facade versions it speaks,
# so in order to be compatible forwards and backwards we speak a
# common facade versions.
if (name
not in client_facades) and (name
not in self.specified_facades):
# if a facade is required but the client doesn't know about
# it, then log a warning.
log.warning('unknown facade {}'.format(name))
try:
known = []
# allow the ability to specify a set of facade versions, so the
# client can define the non-conservitive facade client pinning.
if name in self.specified_facades:
known = self.specified_facades[name]['versions']
elif name in client_facades:
known = client_facades[name]['versions']
else:
raise errors.JujuConnectionError(
"unexpected facade {}".format(name))
discovered = facade['versions']
version = max(set(known).intersection(set(discovered)))
except ValueError:
# this can occur if known is [1, 2] and discovered is [3, 4]
# there is just no way to know how to communicate with the
# facades we're trying to call.
log.warning(
"unknown common facade version for {}".format(name))
except errors.JujuConnectionError:
# If the facade isn't with in the local facades then it's not
# possible to reason about what version should be used. In this
# case we should log the facade was found, but we couldn't
# handle it.
log.warning(
"unexpected facade {} found, unable to decipher version to use"
.format(name))
else:
self.facades[name] = version