better fail metric labels

Author: mrlevitas

reddit_decider/__init__.py

@@ -1024,15 +1024,15 @@ def inc_failure_counter(failure_type: str) -> None:
 
         # check for `span`'s presence
         if span is None:
-            inc_failure_counter("missing_span")
+            inc_failure_counter("missing:'span'")
             logger.debug("`span` is `None` in reddit_decider `make_object_for_context()`.")
             return self._minimal_decider(internal=rs_decider, name=name, span=span)
 
         # check for `span.context`'s presence
         request = getattr(span, "context", None)
 
         if request is None:
-            inc_failure_counter("missing_span_context")
+            inc_failure_counter("missing:'span.context'")
             return self._minimal_decider(
                 internal=rs_decider,
                 name=name,
@@ -1060,6 +1060,7 @@ def inc_failure_counter(failure_type: str) -> None:
         ec = getattr(request, "edge_context", None)
         # if `edge_context` is inaccessible, bail field extraction early
         if ec is None:
+            inc_failure_counter("missing:'request.edge_context'")
             return self._minimal_decider(
                 internal=rs_decider,
                 name=name,

tests/decider_tests.py

@@ -239,7 +239,7 @@ def test_make_object_for_context_without_span(self, metric_counter_labels):
             metric_counter_labels.assert_called_once_with(
                 operation="make_object_for_context",
                 success="false",
-                error_type="missing_span",
+                error_type="missing:'span'",
                 pkg_version=mock.ANY,
             )
 
@@ -273,7 +273,7 @@ def test_make_object_for_context_with_span_context_as_None(self, metric_counter_
             metric_counter_labels.assert_called_once_with(
                 operation="make_object_for_context",
                 success="false",
-                error_type="missing_span_context",
+                error_type="missing:'span_context'",
                 pkg_version=mock.ANY,
             )