MockTracer cannot start span with a parent span

[moonshine-fish]

opentracing-python/opentracing/mocktracer/tracer.py

Line 162 in aef28a7

if parent_ctx._baggage is not None:

If I want to test with MockTracer, and in my business code it calls start_span with child_of parameter, an error will occur as original SpanContext doesn't have _baggage property

        # Assemble the child ctx
        ctx = SpanContext(span_id=self._generate_id())
        if parent_ctx is not None:
>           if parent_ctx._baggage is not None:
E           AttributeError: 'SpanContext' object has no attribute '_baggage'

opentracing.mocktracer.SpanContext has _baggage property, but how can I use it in my business code?

[yurishkuro]

Please refer to the API and not to private fields of implementation classes.

opentracing-python/opentracing/span.py

Lines 168 to 190 in aef28a7

	def set_baggage_item(self, key, value):
	"""Stores a Baggage item in the :class:`Span` as a key/value pair.
	Enables powerful distributed context propagation functionality where
	arbitrary application data can be carried along the full path of
	request execution throughout the system.
	Note 1: Baggage is only propagated to the future (recursive) children
	of this :class:`Span`.
	Note 2: Baggage is sent in-band with every subsequent local and remote
	calls, so this feature must be used with care.
	:param key: Baggage item key
	:type key: str
	:param value: Baggage item value
	:type value: str
	:rtype: Span
	:return: itself, for chaining the calls.
	"""
	return self

opentracing-python/opentracing/span.py

Lines 192 to 201 in aef28a7

	def get_baggage_item(self, key):
	"""Retrieves value of the baggage item with the given key.
	:param key: key of the baggage item
	:type key: str
	:rtype: str
	:return: value of the baggage item with given key, or ``None``.
	"""
	return None