ref(transactions): Bring back discard transactions feature flag

CHANGELOG.md

@@ -32,6 +32,7 @@
 - Match patterns iteratively instead of recursively. ([#6188](https://github.com/getsentry/relay/pull/6188))
 - Expand size of outcome quantities from `u32` to `u64`. ([#6133](https://github.com/getsentry/relay/pull/6133))
 - Internally handle outcomes as metrics. ([#6107](https://github.com/getsentry/relay/pull/6107))
+- Re-introduce `projects:discard-transaction` feature flag. ([#6199](https://github.com/getsentry/relay/pull/6199))
 - Have relay generate metric billing outcomes. ([#6066](https://github.com/getsentry/relay/pull/6066))
 - Update sentry-conventions to 0.12.0.
 - Update sentry-conventions to 0.13.0. ([#6139](https://github.com/getsentry/relay/pull/6139))

relay-filter/src/common.rs

@@ -42,6 +42,11 @@ pub enum FilterStatKey {
     /// Filtered due to the namespace being disabled.
     DisabledNamespace,
 
+    /// Filtered by Relay.
+    ///
+    /// This is currently only used for transactions, after spans have been extracted.
+    Discarded,
+
     /// Filtered due to a generic filter.
     GenericFilter(String),
 }
@@ -73,6 +78,7 @@ impl FilterStatKey {
             FilterStatKey::FilteredTransactions => "filtered-transaction",
             FilterStatKey::DeniedName => "denied-name",
             FilterStatKey::DisabledNamespace => "disabled-namespace",
+            FilterStatKey::Discarded => "discarded",
             FilterStatKey::GenericFilter(filter_identifier) => {
                 return Cow::Owned(filter_identifier);
             }

relay-server/src/processing/transactions/types/output.rs

@@ -53,6 +53,8 @@ impl Forward for TransactionOutput {
         ctx: ForwardContext<'_>,
     ) -> Result<(), Rejected<()>> {
         use crate::services::store::StoreEvent;
+        use relay_dynamic_config::Feature;
+        use relay_filter::FilterStatKey;
 
         let (spans, transaction) = match self {
             TransactionOutput::Full(managed) => {
@@ -67,7 +69,7 @@ impl Forward for TransactionOutput {
 
         let performance_issues_spans = ctx
             .project_info
-            .has_feature(relay_dynamic_config::Feature::PerformanceIssuesSpans);
+            .has_feature(Feature::PerformanceIssuesSpans);
 
         if let Some(spans) = spans {
             let event_id = transaction.headers.event_id();
@@ -112,7 +114,11 @@ impl Forward for TransactionOutput {
             (profile, event)
         });
 
-        s.send_event(event);
+        let discard_transactions = ctx.project_info.has_feature(Feature::DiscardTransaction);
+        match discard_transactions {
+            false => s.send_event(event),
+            true => drop(event.reject_err(Outcome::Filtered(FilterStatKey::Discarded))),
+        }
 
         if let Some(profile) = profile.transpose() {
             s.send_to_store(profile.map(|p, _| store::convert_profile(p, true, ctx)));

tests/integration/test_spans.py

@@ -14,8 +14,6 @@
 
 TEST_CONFIG = {
     "aggregator": {
-        "bucket_interval": 1,
-        "initial_delay": 0,
         "shift_key": "none",
     }
 }
@@ -1070,6 +1068,42 @@ def summarize_outcomes():
         assert span_usage_metric() == 2
 
 
+def test_discard_transaction(
+    mini_sentry,
+    relay_with_processing,
+    transactions_consumer,
+    spans_consumer,
+    outcomes_consumer,
+):
+    transactions_consumer = transactions_consumer()
+    spans_consumer = spans_consumer()
+    outcomes_consumer = outcomes_consumer()
+
+    project_id = 42
+    project_config = mini_sentry.add_full_project_config(project_id)
+    project_config["config"].setdefault("features", []).append(
+        "projects:discard-transaction"
+    )
+
+    relay = relay_with_processing(options=TEST_CONFIG)
+
+    start = datetime.now(timezone.utc)
+    end = start + timedelta(seconds=1)
+
+    relay.send_envelope(project_id, envelope_with_transaction_and_spans(start, end))
+
+    # We have one nested span and the transaction itself becomes a span
+    spans = spans_consumer.get_spans(n=2)
+    assert len(spans) == 2
+
+    outcomes = outcomes_consumer.get_outcomes()
+    assert [(o["category"], o["outcome"], o["reason"]) for o in outcomes] == [
+        (9, 1, "discarded"),  # TransactionIndexed, Filtered
+    ]
+
+    transactions_consumer.assert_empty()
+
+
 def test_span_filtering_with_generic_inbound_filter(
     mini_sentry, relay_with_processing, spans_consumer, outcomes_consumer
 ):