[observability] Update Python calltracer implementation (#33899)

src/python/grpcio_observability/grpc_observability/client_call_tracer.cc

@@ -56,10 +56,24 @@ void PythonOpenCensusCallTracer::GenerateContext() {}
 
 void PythonOpenCensusCallTracer::RecordAnnotation(
     absl::string_view annotation) {
-  // If tracing is disabled, the following will be a no-op.
+  if (!context_.SpanContext().IsSampled()) {
+    return;
+  }
   context_.AddSpanAnnotation(annotation);
 }
 
+void PythonOpenCensusCallTracer::RecordAnnotation(
+    const Annotation& annotation) {
+  if (!context_.SpanContext().IsSampled()) {
+    return;
+  }
+
+  switch (annotation.type()) {
+    default:
+      context_.AddSpanAnnotation(annotation.ToString());
+  }
+}
+
 PythonOpenCensusCallTracer::~PythonOpenCensusCallTracer() {
   if (PythonCensusStatsEnabled()) {
     context_.Labels().emplace_back(kClientMethod, std::string(method_));
@@ -275,8 +289,22 @@ void PythonOpenCensusCallTracer::PythonOpenCensusCallAttemptTracer::RecordEnd(
 
 void PythonOpenCensusCallTracer::PythonOpenCensusCallAttemptTracer::
     RecordAnnotation(absl::string_view annotation) {
-  // If tracing is disabled, the following will be a no-op.
+  if (!context_.SpanContext().IsSampled()) {
+    return;
+  }
   context_.AddSpanAnnotation(annotation);
 }
 
+void PythonOpenCensusCallTracer::PythonOpenCensusCallAttemptTracer::
+    RecordAnnotation(const Annotation& annotation) {
+  if (!context_.SpanContext().IsSampled()) {
+    return;
+  }
+
+  switch (annotation.type()) {
+    default:
+      context_.AddSpanAnnotation(annotation.ToString());
+  }
+}
+
 }  // namespace grpc_observability

src/python/grpcio_observability/grpc_observability/client_call_tracer.h

@@ -76,6 +76,7 @@ class PythonOpenCensusCallTracer : public grpc_core::ClientCallTracer {
     void RecordCancel(grpc_error_handle cancel_error) override;
     void RecordEnd(const gpr_timespec& /*latency*/) override;
     void RecordAnnotation(absl::string_view annotation) override;
+    void RecordAnnotation(const Annotation& annotation) override;
 
    private:
     // Maximum size of trace context is sent on the wire.
@@ -115,6 +116,7 @@ class PythonOpenCensusCallTracer : public grpc_core::ClientCallTracer {
       bool is_transparent_retry) override;
 
   void RecordAnnotation(absl::string_view annotation) override;
+  void RecordAnnotation(const Annotation& annotation) override;
 
  private:
   PythonCensusContext CreateCensusContextForCallAttempt();

src/python/grpcio_observability/grpc_observability/server_call_tracer.cc

@@ -150,9 +150,23 @@ class PythonOpenCensusServerCallTracer : public grpc_core::ServerCallTracer {
   void RecordEnd(const grpc_call_final_info* final_info) override;
 
   void RecordAnnotation(absl::string_view annotation) override {
+    if (!context_.SpanContext().IsSampled()) {
+      return;
+    }
     context_.AddSpanAnnotation(annotation);
   }
 
+  void RecordAnnotation(const Annotation& annotation) override {
+    if (!context_.SpanContext().IsSampled()) {
+      return;
+    }
+
+    switch (annotation.type()) {
+      default:
+        context_.AddSpanAnnotation(annotation.ToString());
+    }
+  }
+
  private:
   PythonCensusContext context_;
   // server method