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)