OpenTracing

This module is available only if you have opentracing installed

trace_future

satella.opentracing.trace_future(future, span)

Install a handler that will close a span upon a future completing, attaching the exception contents if the future ends with an exception.

Parameters:
  • future (Union[ResponseFuture, Future]) – can be either a normal Future or a Cassandra’s ResponseFuture

  • span (Span) – span to close on future’s completion

trace_function

satella.opentracing.trace_function(tracer, name, tags=None, tags_factory=None)

Return a decorator that will trace the execution of a given function using tracer.start_active_span.

Can optionally construct it’s tags from a predicate building, example:

>>> class Device:
>>>     device_id = 'test'
>>> @trace_function(tracer, 'Processing', tags_factory=[('device_id', x[0].device_id)])
>>> def process(device: Device):
>>>     ...
Parameters:
  • tracer – tracer to use

  • name (str) – Name of the trace

  • tags (Optional[dict]) – optional tags to use

  • tags_factory (Optional[Union[Dict[str, Callable], List[Tuple[str, Callable]]]]) – a list of tuple (tag name, callable that is called with *args and **kwargs passed to this function as a sole argument). Extra tags will be generated from this. Can be also a dict.

trace_exception

satella.opentracing.trace_exception(span, exc_type=None, exc_val=None, exc_tb=None, max_tb_length=None)

Log an exception’s information to the chosen span, as logs and tags.

Parameters:
  • span (Optional[Span]) – span to log into or None for a no-op

  • exc_type (Optional[Type[Exception]]) – exception type. If None this will be taken from sys.exc_info.

  • exc_val (Optional[Exception]) – exception value. If None this will be taken from sys.exc_info.

  • exc_tb (Optional[TracebackType]) – exception traceback. If None this will be taken from sys.exc_info.

  • max_tb_length (Optional[int]) – maximum traceback length. If traceback is longer than that, it will be trimmed. The default is 65536. You can set it by satella.opentracing.set_maximum_traceback_length()

Return type:

None

set_maximum_traceback_length

satella.opentracing.set_maximum_traceback_length(length)

Set a new maximum traceback length

Parameters:

length (int) – maximum traceback length, in bytes

Return type:

None