Add option to enable propagation of parent span tags

DoumanAsh · DoumanAsh · commit 665dca235f40 · 2025-03-01T18:43:13.000+09:00
diff --git a/sentry-tracing/src/converters.rs b/sentry-tracing/src/converters.rs
@@ -9,7 +9,7 @@ use tracing_subscriber::layer::Context;
 use tracing_subscriber::registry::LookupSpan;
 
 use super::layer::SentrySpanData;
-use crate::TAGS_PREFIX;
+use crate::{SpanPropagation, TAGS_PREFIX};
 
 /// Converts a [`tracing_core::Level`] to a Sentry [`Level`]
 fn convert_tracing_level(level: &tracing_core::Level) -> Level {
@@ -53,40 +53,34 @@ fn extract_event_data(event: &tracing_core::Event) -> (Option<String>, FieldVisi
 
 fn extract_event_data_with_context<S>(
     event: &tracing_core::Event,
-    ctx: Option<Context<S>>,
+    ctx: Option<(SpanPropagation, Context<S>)>,
 ) -> (Option<String>, FieldVisitor)
 where
     S: Subscriber + for<'a> LookupSpan<'a>,
 {
     let (message, mut visitor) = extract_event_data(event);
 
     // Add the context fields of every parent span.
-    let current_span = ctx.as_ref().and_then(|ctx| {
+    let current_span = ctx.as_ref().and_then(|(propagation, ctx)| {
         event
             .parent()
-            .and_then(|id| ctx.span(id))
-            .or_else(|| ctx.lookup_current())
+            .and_then(|id| ctx.span(id).map(|span| (*propagation, span)))
+            .or_else(|| ctx.lookup_current().map(|span| (*propagation, span)))
     });
-    if let Some(span) = current_span {
+    if let Some((propagation, span)) = current_span {
         for span in span.scope() {
             let name = span.name();
             let ext = span.extensions();
             if let Some(span_data) = ext.get::<SentrySpanData>() {
                 match &span_data.sentry_span {
                     TransactionOrSpan::Span(span) => {
                         for (key, value) in span.data().iter() {
-                            if key != "message" {
-                                let key = format!("{}:{}", name, key);
-                                visitor.json_values.insert(key, value.clone());
-                            }
+                            visitor.propagate_span_attr(key, value, propagation, name);
                         }
                     }
                     TransactionOrSpan::Transaction(transaction) => {
                         for (key, value) in transaction.data().iter() {
-                            if key != "message" {
-                                let key = format!("{}:{}", name, key);
-                                visitor.json_values.insert(key, value.clone());
-                            }
+                            visitor.propagate_span_attr(key, value, propagation, name);
                         }
                     }
                 }
@@ -105,6 +99,26 @@ pub(crate) struct FieldVisitor {
 }
 
 impl FieldVisitor {
+    fn propagate_span_attr(
+        &mut self,
+        key: &str,
+        value: &Value,
+        span_propagation: SpanPropagation,
+        span_name: &str,
+    ) {
+        if key != "message" {
+            if span_propagation.is_tags_enabled() && key.starts_with(TAGS_PREFIX) {
+                //Propagate tags as it is, it will be extracted later on
+                if !self.json_values.contains_key(key) {
+                    self.json_values.insert(key.to_owned(), value.clone());
+                }
+            } else if span_propagation.is_attrs_enabled() {
+                let key = format!("{}:{}", span_name, key);
+                self.json_values.insert(key, value.clone());
+            }
+        }
+    }
+
     fn record<T: Into<Value>>(&mut self, field: &Field, value: T) {
         self.json_values
             .insert(field.name().to_owned(), value.into());
@@ -143,12 +157,17 @@ impl Visit for FieldVisitor {
 /// Creates a [`Breadcrumb`] from a given [`tracing_core::Event`]
 pub fn breadcrumb_from_event<'context, S>(
     event: &tracing_core::Event,
-    ctx: impl Into<Option<Context<'context, S>>>,
+    ctx: impl Into<Option<(SpanPropagation, Context<'context, S>)>>,
 ) -> Breadcrumb
 where
     S: Subscriber + for<'a> LookupSpan<'a>,
 {
-    let (message, visitor) = extract_event_data_with_context(event, ctx.into());
+    let ctx = match ctx.into() {
+        Some((propagation, ctx)) if propagation.is_attrs_enabled() => Some((propagation, ctx)),
+        //Breadcrumb has no tags, so propagate only attributes
+        _ => None,
+    };
+    let (message, visitor) = extract_event_data_with_context(event, ctx);
     Breadcrumb {
         category: Some(event.metadata().target().to_owned()),
         ty: "log".into(),
@@ -219,7 +238,7 @@ fn contexts_from_event(
 /// Creates an [`Event`] from a given [`tracing_core::Event`]
 pub fn event_from_event<'context, S>(
     event: &tracing_core::Event,
-    ctx: impl Into<Option<Context<'context, S>>>,
+    ctx: impl Into<Option<(SpanPropagation, Context<'context, S>)>>,
 ) -> Event<'static>
 where
     S: Subscriber + for<'a> LookupSpan<'a>,
@@ -239,7 +258,7 @@ where
 /// Creates an exception [`Event`] from a given [`tracing_core::Event`]
 pub fn exception_from_event<'context, S>(
     event: &tracing_core::Event,
-    ctx: impl Into<Option<Context<'context, S>>>,
+    ctx: impl Into<Option<(SpanPropagation, Context<'context, S>)>>,
 ) -> Event<'static>
 where
     S: Subscriber + for<'a> LookupSpan<'a>,
diff --git a/sentry-tracing/src/layer.rs b/sentry-tracing/src/layer.rs
@@ -11,7 +11,7 @@ use tracing_subscriber::layer::{Context, Layer};
 use tracing_subscriber::registry::LookupSpan;
 
 use crate::converters::*;
-use crate::TAGS_PREFIX;
+use crate::{SpanPropagation, TAGS_PREFIX};
 
 /// The action that Sentry should perform for a [`Metadata`]
 #[derive(Debug, Clone, Copy)]
@@ -70,7 +70,7 @@ pub struct SentryLayer<S> {
 
     span_filter: Box<dyn Fn(&Metadata) -> bool + Send + Sync>,
 
-    with_span_attributes: bool,
+    span_propagation: Option<SpanPropagation>,
 }
 
 impl<S> SentryLayer<S> {
@@ -123,8 +123,14 @@ impl<S> SentryLayer<S> {
     /// the [traces_sample_rate][sentry_core::ClientOptions::traces_sample_rate] to `1.0`
     /// while configuring your sentry client.
     #[must_use]
-    pub fn enable_span_attributes(mut self) -> Self {
-        self.with_span_attributes = true;
+    pub fn enable_span_attributes(self) -> Self {
+        self.enable_span_propagation(SpanPropagation::Attributes)
+    }
+
+    #[must_use]
+    /// Configures span propagation for events' creation
+    pub fn enable_span_propagation(mut self, propagation: SpanPropagation) -> Self {
+        self.span_propagation = Some(propagation);
         self
     }
 }
@@ -140,7 +146,7 @@ where
 
             span_filter: Box::new(default_span_filter),
 
-            with_span_attributes: false,
+            span_propagation: None,
         }
     }
 }
@@ -210,7 +216,7 @@ where
         let item = match &self.event_mapper {
             Some(mapper) => mapper(event, ctx),
             None => {
-                let span_ctx = self.with_span_attributes.then_some(ctx);
+                let span_ctx = self.span_propagation.map(|propagation| (propagation, ctx));
                 match (self.event_filter)(event.metadata()) {
                     EventFilter::Ignore => EventMapping::Ignore,
                     EventFilter::Breadcrumb => {
diff --git a/sentry-tracing/src/lib.rs b/sentry-tracing/src/lib.rs
@@ -147,3 +147,32 @@ pub use converters::*;
 pub use layer::*;
 
 const TAGS_PREFIX: &str = "tags.";
+
+#[derive(Debug, Clone, Copy)]
+/// Controls propagation of span data when creating event
+///
+/// Note that the root span is considered a [transaction][sentry_core::protocol::Transaction]
+/// so its context will only be grabbed only if you set the transaction to be sampled.
+/// The most straightforward way to do this is to set
+/// the [traces_sample_rate][sentry_core::ClientOptions::traces_sample_rate] to `1.0`
+/// while configuring your sentry client.
+pub enum SpanPropagation {
+    /// Collects all attributes prefixed with span name
+    Attributes,
+    /// Accumulates tags from within attributes as event tags, without overriding existing tags
+    Tags,
+    /// Collects both tags and attributes
+    All,
+}
+
+impl SpanPropagation {
+    #[inline(always)]
+    pub(crate) const fn is_tags_enabled(&self) -> bool {
+        matches!(self, Self::Tags | Self::All)
+    }
+
+    #[inline(always)]
+    pub(crate) const fn is_attrs_enabled(&self) -> bool {
+        matches!(self, Self::Attributes | Self::All)
+    }
+}
