fix(tracing): calculate traceid in python not clickhouse to avoid nullable checks (#52061)

Author: frankh

products/tracing/backend/logic.py

@@ -176,11 +176,12 @@ def where(self) -> ast.Expr:
             )
 
         if self.query.traceId:
+            trace_id_b64 = base64.b64encode(bytes.fromhex(self.query.traceId)).decode("ascii")
             exprs.append(
                 parse_expr(
-                    "trace_id = assumeNotNull(base64Encode(unhex({traceId})))",
+                    "trace_id = {traceId}",
                     placeholders={
-                        "traceId": ast.Constant(value=self.query.traceId),
+                        "traceId": ast.Constant(value=trace_id_b64),
                     },
                 )
             )

products/tracing/backend/presentation/views.py

@@ -84,6 +84,11 @@ def query(self, request: Request, *args, **kwargs) -> Response:
     def trace(self, request: Request, trace_id: str, *args, **kwargs) -> Response:
         query_data = request.data or {}
         date_range = self.get_model(query_data.get("dateRange", {"date_from": "-24h"}), DateRange)
+        try:
+            # verify the trace_id is valid
+            base64.b64encode(bytes.fromhex(trace_id)).decode("ascii")
+        except ValueError:
+            return Response(status=status.HTTP_400_BAD_REQUEST)
 
         spans_query = TraceSpansQuery(
             dateRange=date_range,