feat(logs): Count log envelopes with dynamic sampling context (#5420)

Author: jjbayer

relay-server/src/processing/logs/mod.rs

@@ -138,6 +138,7 @@ impl processing::Processor for LogsProcessor {
         ctx: Context<'_>,
     ) -> Result<Output<Self::Output>, Rejected<Error>> {
         validate::container(&logs).reject(&logs)?;
+        validate::dsc(&logs);
 
         // Fast filters, which do not need expanded logs.
         filter::feature_flag(ctx).reject(&logs)?;

relay-server/src/processing/logs/validate.rs

@@ -1,5 +1,6 @@
 use crate::processing::Managed;
 use crate::processing::logs::{Error, Result, SerializedLogs};
+use crate::statsd::RelayCounters;
 
 /// Validates that there is only a single log container processed at a time.
 ///
@@ -18,3 +19,17 @@ pub fn container(logs: &Managed<SerializedLogs>) -> Result<()> {
 
     Ok(())
 }
+
+/// Validate that the envelope has no trace context header.
+///
+/// For now, this only emits a metric so we can verify that logs envelopes do not
+/// contain a trace context.
+pub fn dsc(logs: &Managed<SerializedLogs>) {
+    relay_statsd::metric!(
+        counter(RelayCounters::EnvelopeWithLogs) += 1,
+        dsc = match logs.headers.dsc() {
+            Some(_) => "yes",
+            None => "no",
+        }
+    )
+}

relay-server/src/statsd.rs

@@ -936,6 +936,11 @@ pub enum RelayCounters {
     /// - `type`: `envelope` or `attachment_v2`
     #[cfg(feature = "processing")]
     AttachmentUpload,
+    /// Whether a logs envelope has a trace context header or not
+    ///
+    /// This metric is tagged with:
+    /// - `dsc`: yes or no
+    EnvelopeWithLogs,
 }
 
 impl CounterMetric for RelayCounters {
@@ -992,6 +997,7 @@ impl CounterMetric for RelayCounters {
             RelayCounters::SamplingDecision => "sampling.decision",
             #[cfg(feature = "processing")]
             RelayCounters::AttachmentUpload => "attachment.upload",
+            RelayCounters::EnvelopeWithLogs => "logs.envelope",
         }
     }
 }