Conform zipkin traceId, spanId, parentId specs

Using v1 API defined in https://github.com/openzipkin/zipkin-api/blob/7692ca7be4dc3be9225db550d60c4d30e6e9ec59/zipkin-api.yaml

traceId to 32 character lowercase hex string
spanId to 16 character lowercase hex string
parentId to be absent for root span

baseplate/__init__.py

@@ -122,8 +122,9 @@ def new(cls) -> "TraceInfo":
         with any upstream requests.
 
         """
-        trace_id = random.getrandbits(64)
-        return cls(trace_id=trace_id, parent_id=None, span_id=trace_id, sampled=None, flags=None)
+        trace_id = "{0:0{1}x}".format(random.getrandbits(128), 32)
+        span_id = "{0:0{1}x}".format(random.getrandbits(64), 16)
+        return cls(trace_id=trace_id, parent_id=None, span_id=span_id, sampled=None, flags=None)
 
     @classmethod
     def from_upstream(
@@ -767,7 +768,8 @@ def make_child(
         :param component_name: Name to identify local component
             this span is recording in if it is a local span.
         """
-        span_id = random.getrandbits(64)
+        span_id = "{0:0{1}x}".format(random.getrandbits(64), 16)
+
 
         context_copy = self.context.clone()
         span: Span

baseplate/observers/tracing.py

@@ -279,7 +279,9 @@ def _to_span_obj(
             "binaryAnnotations": binary_annotations,
         }
 
-        span["parentId"] = self.span.parent_id or 0
+        if self.span.parent_id:
+            span["parentId"] = self.span.parent_id
+
         return span
 
     def _serialize(self) -> Dict[str, Any]: