fix(tracing): record remote sample rate provenance

Author: mabdinur

ddtrace/_trace/product.py

@@ -3,6 +3,7 @@
 
 from envier import En
 
+from ddtrace.internal.constants import REMOTE_RATE_PROVENANCE
 from ddtrace.internal.logger import get_logger
 from ddtrace.internal.native import RemoteConfigCapabilities
 from ddtrace.internal.settings import env
@@ -138,7 +139,7 @@ def _convert_rc_trace_sampling_rules(lib_config) -> t.Optional[str]:
                 rule["tags"] = {tag["key"]: tag["value_glob"] for tag in rule["tags"]}
 
     if global_sample_rate is not None:
-        rc_rules.append({"sample_rate": global_sample_rate})
+        rc_rules.append({"sample_rate": global_sample_rate, "provenance": REMOTE_RATE_PROVENANCE})
 
     if rc_rules:
         return json.dumps(rc_rules)

ddtrace/_trace/sampler.py

@@ -14,6 +14,7 @@
 
 from ..constants import ENV_KEY
 from ..internal.constants import MAX_UINT_64BITS
+from ..internal.constants import REMOTE_RATE_PROVENANCE
 from ..internal.constants import SAMPLING_HASH_MODULO
 from ..internal.constants import SAMPLING_KNUTH_FACTOR
 from ..internal.constants import SamplingMechanism
@@ -24,7 +25,7 @@
 from .sampling_rule import SamplingRule
 
 
-PROVENANCE_ORDER = ["customer", "dynamic", "default"]
+PROVENANCE_ORDER = ["customer", "dynamic", REMOTE_RATE_PROVENANCE, "default"]
 
 
 log = get_logger(__name__)
@@ -211,7 +212,7 @@ def sample(self, span: Span) -> bool:
         return sampled
 
     def _get_sampling_mechanism(self, matched_rule: Optional[SamplingRule], agent_service_based: bool) -> int:
-        if matched_rule and matched_rule.provenance == "customer":
+        if matched_rule and matched_rule.provenance in ("customer", REMOTE_RATE_PROVENANCE):
             return SamplingMechanism.REMOTE_USER_TRACE_SAMPLING_RULE
         elif matched_rule and matched_rule.provenance == "dynamic":
             return SamplingMechanism.REMOTE_DYNAMIC_TRACE_SAMPLING_RULE

ddtrace/internal/constants.py

@@ -158,6 +158,8 @@ def __getitem__(self, k: str) -> Any:
 LOG_ATTR_VALUE_ZERO = "0"
 LOG_ATTR_VALUE_EMPTY = ""
 
+REMOTE_RATE_PROVENANCE = "remote_rate"
+
 
 class SamplingMechanism(object):
     DEFAULT = 0

tests/internal/test_settings.py

@@ -376,25 +376,36 @@ def test_remoteconfig_global_sample_rate_and_rules(ddtrace_run_python_code_in_su
 with tracer.trace("sample_rate") as span:
     pass
 assert span.get_metric("_dd.rule_psr") == 0.2
-assert span.get_tag("_dd.p.dm") == "-3"
+assert span.get_tag("_dd.p.dm") == "-11"
 # Ensure the previous sampling rule with operation name "rules" is not used
 with tracer.trace("rules") as span:
     pass
 assert span.get_metric("_dd.rule_psr") == 0.2
-assert span.get_tag("_dd.p.dm") == "-3"
+assert span.get_tag("_dd.p.dm") == "-11"
 
-# Set a new sampling rules via rc
-call_apm_tracing_rc(_base_rc_config({"tracing_sampling_rate": 0.3}), config)
+# Set a dynamic sampling rule and a default sampling rate via rc
+call_apm_tracing_rc(_base_rc_config({
+    "tracing_sampling_rate": 0.3,
+    "tracing_sampling_rules": [
+        {
+            "service": "*",
+            "name": "rules",
+            "resource": "*",
+            "provenance": "dynamic",
+            "sample_rate": 0.1,
+        }
+    ],
+}), config)
 # Ensure that the new default sampling rate is used
 with tracer.trace("sample_rate") as span:
     pass
 assert span.get_metric("_dd.rule_psr") == 0.3
-assert span.get_tag("_dd.p.dm") == "-3"
-# Ensure the previous sampling rule with operation name "rules" is not used
+assert span.get_tag("_dd.p.dm") == "-11"
+# Ensure that the dynamic sampling rule takes precedence over the default rate
 with tracer.trace("rules") as span:
     pass
-assert span.get_metric("_dd.rule_psr") == 0.3
-assert span.get_tag("_dd.p.dm") == "-3"
+assert span.get_metric("_dd.rule_psr") == 0.1
+assert span.get_tag("_dd.p.dm") == "-12"
 
 # Remove all sampling rules from remote config
 call_apm_tracing_rc(_base_rc_config({}), config)