Refactor is_valid to be an instance attribute (#1005)

opentelemetry-api/CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## Unreleased
 
+- Refactor `SpanContext.is_valid` from a method to a data attribute
+  ([#1005](https://github.com/open-telemetry/opentelemetry-python/pull/1005))
 - Moved samplers from API to SDK
   ([#1023](https://github.com/open-telemetry/opentelemetry-python/pull/1023))
 

opentelemetry-api/src/opentelemetry/trace/span.py

@@ -187,6 +187,10 @@ def __init__(
         self.trace_flags = trace_flags
         self.trace_state = trace_state
         self.is_remote = is_remote
+        self.is_valid = (
+            self.trace_id != INVALID_TRACE_ID
+            and self.span_id != INVALID_SPAN_ID
+        )
 
     def __repr__(self) -> str:
         return (
@@ -199,20 +203,6 @@ def __repr__(self) -> str:
             self.is_remote,
         )
 
-    def is_valid(self) -> bool:
-        """Get whether this `SpanContext` is valid.
-
-        A `SpanContext` is said to be invalid if its trace ID or span ID is
-        invalid (i.e. ``0``).
-
-        Returns:
-            True if the `SpanContext` is valid, false otherwise.
-        """
-        return (
-            self.trace_id != INVALID_TRACE_ID
-            and self.span_id != INVALID_SPAN_ID
-        )
-
 
 class DefaultSpan(Span):
     """The default Span that is used when no Span implementation is available.

opentelemetry-api/tests/trace/test_defaultspan.py

@@ -32,4 +32,4 @@ def test_ctor(self):
     def test_invalid_span(self):
         self.assertIsNotNone(trace.INVALID_SPAN)
         self.assertIsNotNone(trace.INVALID_SPAN.get_context())
-        self.assertFalse(trace.INVALID_SPAN.get_context().is_valid())
+        self.assertFalse(trace.INVALID_SPAN.get_context().is_valid)

opentelemetry-sdk/src/opentelemetry/sdk/trace/__init__.py

@@ -774,7 +774,7 @@ def start_span(  # pylint: disable=too-many-locals
         ):
             raise TypeError("parent must be a Span, SpanContext or None.")
 
-        if parent_context is None or not parent_context.is_valid():
+        if parent_context is None or not parent_context.is_valid:
             parent = parent_context = None
             trace_id = generate_trace_id()
             trace_flags = None

opentelemetry-sdk/tests/trace/test_trace.py

@@ -165,7 +165,7 @@ def test_start_span_invalid_spancontext(self):
         new_span = tracer.start_span(
             "root", parent=trace_api.INVALID_SPAN_CONTEXT
         )
-        self.assertTrue(new_span.context.is_valid())
+        self.assertTrue(new_span.context.is_valid)
         self.assertIsNone(new_span.parent)
 
     def test_instrumentation_info(self):