def _validate_start(self, *args, **kwargs):
# check base class invariants first
if not self.connection:
# only if we have connection we can expect some data on it
# at the latest "just before start" we need connection
raise NoConnectionProvided(self)
# ----------------------------------------------------------------------
# We intentionally do not check if connection is open here.
# In such case net result anyway will be failed/timeouted observer -
# - so, user will need to investigate "why".
# Checking connection state would benefit in early detection of:
# "error condition - no chance to succeed since connection is closed".
# However, drawback is a requirement on connection to have is_open() API
# We choose minimalistic dependency over better troubleshooting support.
# ----------------------------------------------------------------------
if self.timeout <= 0.0:
raise ConnectionObserverTimeout(self, self.timeout, "before run", "timeout is not positive value")
def _validate_start(self, *args, **kwargs):
# check base class invariants first
if not self.connection:
# only if we have connection we can expect some data on it
# at the latest "just before start" we need connection
raise NoConnectionProvided(self)