feat(metrics): Add target_project_id tag to root counter metrics (#4170)

Adds a new tag named `target_project_id` to the `count_per_root_project`
metrics in the spans and transactions namespace. The tag contains the
numeric identifier of the project where the transaction or spans are
sent, in contrast to the root project where the trace originated.

This tag is added so that we can track and display stats about the
individual data volume that flows from a root project into a specific
target project.

The tag key will not be added to static strings in the metrics indexer.
Therefore, it will not be possible run cross-org queries that filter or
group by this tag.

CHANGELOG.md

@@ -9,7 +9,8 @@
 
 **Internal:**
 
-- Add a metric that counts span volume in the root project for dynamic sampling (`c:spans/count_per_root_project@none`) ([#4134](https://github.com/getsentry/relay/pull/4134))
+- Add a metric that counts span volume in the root project for dynamic sampling (`c:spans/count_per_root_project@none`). ([#4134](https://github.com/getsentry/relay/pull/4134))
+- Add a tag `target_project_id` to both root project metrics for dynamic sampling (`c:transactions/count_per_root_project@none` and `c:spans/count_per_root_project@none`) which shows the flow trace traffic from root to target projects. ([#4170](https://github.com/getsentry/relay/pull/4170))
 - Emit `indexed` tag for the usage metrics. ([#4158](https://github.com/getsentry/relay/pull/4158))
 
 ## 24.10.0

relay-server/src/metrics_extraction/event.rs

@@ -1,5 +1,6 @@
 use std::collections::BTreeMap;
 
+use relay_base_schema::project::ProjectId;
 use relay_common::time::UnixTimestamp;
 use relay_dynamic_config::CombinedMetricExtractionConfig;
 use relay_event_normalization::span::description::ScrubMongoDescription;
@@ -54,6 +55,7 @@ pub fn extract_metrics(
     event: &mut Event,
     config: CombinedMetricExtractionConfig<'_>,
     sampling_decision: SamplingDecision,
+    target_project_id: ProjectId,
     max_tag_value_size: usize,
     extract_spans: bool,
 ) -> ExtractedMetrics {
@@ -67,6 +69,7 @@ pub fn extract_metrics(
             event,
             config,
             sampling_decision,
+            target_project_id,
             max_tag_value_size,
             &mut metrics,
         );
@@ -79,6 +82,7 @@ fn extract_span_metrics_for_event(
     event: &mut Event,
     config: CombinedMetricExtractionConfig<'_>,
     sampling_decision: SamplingDecision,
+    target_project_id: ProjectId,
     max_tag_value_size: usize,
     output: &mut ExtractedMetrics,
 ) {
@@ -113,7 +117,13 @@ fn extract_span_metrics_for_event(
         // This function assumes it is only called when span metrics should be extracted, hence we
         // extract the span root counter unconditionally.
         let transaction = transactions::get_transaction_name(event);
-        let bucket = create_span_root_counter(event, transaction, span_count, sampling_decision);
+        let bucket = create_span_root_counter(
+            event,
+            transaction,
+            span_count,
+            sampling_decision,
+            target_project_id,
+        );
         output.sampling_metrics.extend(bucket);
     });
 }
@@ -127,6 +137,7 @@ pub fn create_span_root_counter<T: Extractable>(
     transaction: Option<String>,
     span_count: u32,
     sampling_decision: SamplingDecision,
+    target_project_id: ProjectId,
 ) -> Option<Bucket> {
     if span_count == 0 {
         return None;
@@ -144,6 +155,10 @@ pub fn create_span_root_counter<T: Extractable>(
 
     let mut tags = BTreeMap::new();
     tags.insert("decision".to_owned(), sampling_decision.to_string());
+    tags.insert(
+        "target_project_id".to_owned(),
+        target_project_id.to_string(),
+    );
     if let Some(transaction) = transaction {
         tags.insert("transaction".to_owned(), transaction);
     }
@@ -1267,6 +1282,7 @@ mod tests {
             event.value_mut().as_mut().unwrap(),
             combined_config(features, None).combined(),
             SamplingDecision::Keep,
+            ProjectId::new(4711),
             200,
             true,
         )
@@ -1484,6 +1500,7 @@ mod tests {
             event.value_mut().as_mut().unwrap(),
             combined_config([Feature::ExtractCommonSpanMetricsFromEvent], None).combined(),
             SamplingDecision::Keep,
+            ProjectId::new(4711),
             200,
             true,
         );
@@ -1541,6 +1558,7 @@ mod tests {
             event.value_mut().as_mut().unwrap(),
             combined_config([Feature::ExtractCommonSpanMetricsFromEvent], None).combined(),
             SamplingDecision::Keep,
+            ProjectId::new(4711),
             200,
             true,
         );
@@ -1575,6 +1593,7 @@ mod tests {
             event.value_mut().as_mut().unwrap(),
             combined_config([Feature::ExtractCommonSpanMetricsFromEvent], None).combined(),
             SamplingDecision::Keep,
+            ProjectId::new(4711),
             200,
             true,
         );
@@ -1839,6 +1858,7 @@ mod tests {
             event.value_mut().as_mut().unwrap(),
             combined_config([Feature::ExtractCommonSpanMetricsFromEvent], None).combined(),
             SamplingDecision::Keep,
+            ProjectId::new(4711),
             200,
             true,
         )
@@ -1983,6 +2003,7 @@ mod tests {
             event.value_mut().as_mut().unwrap(),
             config,
             SamplingDecision::Keep,
+            ProjectId::new(4711),
             200,
             true,
         );

relay-server/src/metrics_extraction/transactions/mod.rs

@@ -1,6 +1,7 @@
 use std::collections::{BTreeMap, BTreeSet};
 
 use relay_base_schema::events::EventType;
+use relay_base_schema::project::ProjectId;
 use relay_common::time::UnixTimestamp;
 use relay_dynamic_config::{CombinedMetricExtractionConfig, TransactionMetricsConfig};
 use relay_event_normalization::span::country_subregion::Subregion;
@@ -255,6 +256,7 @@ pub struct TransactionExtractor<'a> {
     pub generic_config: Option<CombinedMetricExtractionConfig<'a>>,
     pub transaction_from_dsc: Option<&'a str>,
     pub sampling_decision: SamplingDecision,
+    pub target_project_id: ProjectId,
     pub has_profile: bool,
 }
 
@@ -434,6 +436,7 @@ impl TransactionExtractor<'_> {
 
             TransactionCPRTags {
                 decision: self.sampling_decision.to_string(),
+                target_project_id: self.target_project_id,
                 universal_tags,
             }
         };
@@ -615,6 +618,7 @@ mod tests {
             generic_config: None,
             transaction_from_dsc: Some("test_transaction"),
             sampling_decision: SamplingDecision::Keep,
+            target_project_id: ProjectId::new(4711),
             has_profile: false,
         };
 
@@ -994,6 +998,7 @@ mod tests {
             generic_config: None,
             transaction_from_dsc: Some("test_transaction"),
             sampling_decision: SamplingDecision::Keep,
+            target_project_id: ProjectId::new(4711),
             has_profile: false,
         };
 
@@ -1169,6 +1174,7 @@ mod tests {
             generic_config: None,
             transaction_from_dsc: Some("test_transaction"),
             sampling_decision: SamplingDecision::Keep,
+            target_project_id: ProjectId::new(4711),
             has_profile: false,
         };
 
@@ -1320,6 +1326,7 @@ mod tests {
             generic_config: None,
             transaction_from_dsc: Some("test_transaction"),
             sampling_decision: SamplingDecision::Keep,
+            target_project_id: ProjectId::new(4711),
             has_profile: false,
         };
 
@@ -1395,6 +1402,7 @@ mod tests {
             generic_config: None,
             transaction_from_dsc: Some("test_transaction"),
             sampling_decision: SamplingDecision::Keep,
+            target_project_id: ProjectId::new(4711),
             has_profile: false,
         };
 
@@ -1560,6 +1568,7 @@ mod tests {
             generic_config: None,
             transaction_from_dsc: Some("test_transaction"),
             sampling_decision: SamplingDecision::Keep,
+            target_project_id: ProjectId::new(4711),
             has_profile: false,
         };
 
@@ -1599,6 +1608,7 @@ mod tests {
             generic_config: None,
             transaction_from_dsc: Some("test_transaction"),
             sampling_decision: SamplingDecision::Keep,
+            target_project_id: ProjectId::new(4711),
             has_profile: false,
         };
 
@@ -1667,6 +1677,7 @@ mod tests {
             generic_config: None,
             transaction_from_dsc: Some("test_transaction"),
             sampling_decision: SamplingDecision::Keep,
+            target_project_id: ProjectId::new(4711),
             has_profile: false,
         };
 
@@ -1773,6 +1784,7 @@ mod tests {
             generic_config: None,
             transaction_from_dsc: Some("test_transaction"),
             sampling_decision: SamplingDecision::Keep,
+            target_project_id: ProjectId::new(4711),
             has_profile: false,
         };
 
@@ -1806,6 +1818,7 @@ mod tests {
             generic_config: None,
             transaction_from_dsc: Some("test_transaction"),
             sampling_decision: SamplingDecision::Keep,
+            target_project_id: ProjectId::new(4711),
             has_profile: false,
         };
 
@@ -1843,6 +1856,7 @@ mod tests {
             generic_config: None,
             transaction_from_dsc: Some("root_transaction"),
             sampling_decision: SamplingDecision::Keep,
+            target_project_id: ProjectId::new(4711),
             has_profile: false,
         };
 
@@ -1860,6 +1874,7 @@ mod tests {
                 ),
                 tags: {
                     "decision": "keep",
+                    "target_project_id": "4711",
                     "transaction": "root_transaction",
                 },
                 metadata: BucketMetadata {
@@ -2112,6 +2127,7 @@ mod tests {
             generic_config: None,
             transaction_from_dsc: Some("test_transaction"),
             sampling_decision: SamplingDecision::Keep,
+            target_project_id: ProjectId::new(4711),
             has_profile: false,
         };
 
@@ -2213,6 +2229,7 @@ mod tests {
             generic_config: Some(combined_config),
             transaction_from_dsc: Some("test_transaction"),
             sampling_decision: SamplingDecision::Keep,
+            target_project_id: ProjectId::new(4711),
             has_profile: false,
         };
 

relay-server/src/metrics_extraction/transactions/types.rs

@@ -2,6 +2,7 @@ use std::borrow::Cow;
 use std::collections::BTreeMap;
 use std::fmt::Display;
 
+use relay_base_schema::project::ProjectId;
 use relay_common::time::UnixTimestamp;
 use relay_metrics::{
     Bucket, BucketMetadata, BucketValue, DistributionType, DurationUnit, MetricNamespace,
@@ -193,13 +194,18 @@ impl From<TransactionMeasurementTags> for BTreeMap<String, String> {
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub struct TransactionCPRTags {
     pub decision: String,
+    pub target_project_id: ProjectId,
     pub universal_tags: CommonTags,
 }
 
 impl From<TransactionCPRTags> for BTreeMap<String, String> {
     fn from(value: TransactionCPRTags) -> Self {
         let mut map: BTreeMap<String, String> = value.universal_tags.into();
         map.insert("decision".to_string(), value.decision);
+        map.insert(
+            "target_project_id".to_string(),
+            value.target_project_id.to_string(),
+        );
         map
     }
 }

relay-server/src/services/processor.rs

@@ -1495,6 +1495,7 @@ impl EnvelopeProcessorService {
             event,
             combined_config,
             sampling_decision,
+            state.project_id,
             self.inner
                 .config
                 .aggregator_config_for(MetricNamespace::Spans)
@@ -1519,6 +1520,7 @@ impl EnvelopeProcessorService {
                 generic_config: Some(combined_config),
                 transaction_from_dsc,
                 sampling_decision,
+                target_project_id: state.project_id,
                 has_profile: profile_id.is_some(),
             };
 

relay-server/src/services/processor/span/processing.rs

@@ -147,8 +147,13 @@ pub fn process(
                     .value()
                     .and_then(|d| d.segment_name.value())
                     .cloned();
-                let bucket =
-                    event::create_span_root_counter(span, transaction, 1, sampling_decision);
+                let bucket = event::create_span_root_counter(
+                    span,
+                    transaction,
+                    1,
+                    sampling_decision,
+                    state.project_id,
+                );
                 state
                     .extracted_metrics
                     .extend_sampling_metrics(bucket, Some(sampling_decision));

tests/integration/test_metrics.py

@@ -919,6 +919,7 @@ def assert_transaction():
         "retention_days": 90,
         "tags": {
             "decision": "drop" if discard_data else "keep",
+            "target_project_id": "42",
             "transaction": "transaction_which_starts_trace",
         },
         "name": "c:transactions/count_per_root_project@none",
@@ -989,7 +990,7 @@ def test_transaction_metrics_count_per_root_project(
         "org_id": 1,
         "project_id": 41,
         "retention_days": 90,
-        "tags": {"decision": "keep", "transaction": "test"},
+        "tags": {"decision": "keep", "target_project_id": "42", "transaction": "test"},
         "name": "c:transactions/count_per_root_project@none",
         "type": "c",
         "value": 1.0,
@@ -1000,7 +1001,7 @@ def test_transaction_metrics_count_per_root_project(
         "org_id": 1,
         "project_id": 42,
         "retention_days": 90,
-        "tags": {"decision": "keep"},
+        "tags": {"decision": "keep", "target_project_id": "42"},
         "name": "c:transactions/count_per_root_project@none",
         "type": "c",
         "value": 2.0,