Include extra trace attributes from env

This allows us to include arbitrary values from the k8s downward API beyond just the pod labels that are included in the trace attributes file. See linkerd/linkerd2#13544 for the corresponding control plane change. Signed-off-by: Scott Fleener <[email protected]>
sfleen · Jan 14, 2025 · bedbace · bedbace
1 parent 387197e
commit bedbace
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Showing 4 changed files with 58 additions and 27 deletions.
diff --git a/linkerd/app/src/env.rs b/linkerd/app/src/env.rs
@@ -149,6 +149,7 @@ const ENV_OUTBOUND_DISABLE_INFORMATIONAL_HEADERS: &str =
 const ENV_TRACE_ATTRIBUTES_PATH: &str = "LINKERD2_PROXY_TRACE_ATTRIBUTES_PATH";
 const ENV_TRACE_PROTOCOL: &str = "LINKERD2_PROXY_TRACE_PROTOCOL";
 const ENV_TRACE_SERVICE_NAME: &str = "LINKERD2_PROXY_TRACE_SERVICE_NAME";
+const ENV_TRACE_EXTRA_ATTRIBUTES: &str = "LINKERD2_PROXY_TRACE_EXTRA_ATTRIBUTES";
 
 /// Constrains which destination names may be used for profile/route discovery.
 ///
@@ -432,6 +433,7 @@ pub fn parse_config<S: Strings>(strings: &S) -> Result<super::Config, EnvError>
     let hostname = strings.get(ENV_HOSTNAME);
 
     let trace_attributes_file_path = strings.get(ENV_TRACE_ATTRIBUTES_PATH);
+    let trace_extra_attributes = strings.get(ENV_TRACE_EXTRA_ATTRIBUTES);
     let trace_protocol = strings.get(ENV_TRACE_PROTOCOL);
     let trace_service_name = strings.get(ENV_TRACE_SERVICE_NAME);
 
@@ -831,12 +833,17 @@ pub fn parse_config<S: Strings>(strings: &S) -> Result<super::Config, EnvError>
             } else {
                 outbound.http_request_queue.failfast_timeout
             };
-            let attributes = trace_attributes_file_path
+            let mut attributes = trace_attributes_file_path
                 .map(|path| match path.and_then(|p| p.parse::<PathBuf>().ok()) {
                     Some(path) => trace::read_trace_attributes(&path),
                     None => HashMap::new(),
                 })
                 .unwrap_or_default();
+            if let Ok(Some(attrs)) = trace_extra_attributes {
+                if !attrs.is_empty() {
+                    attributes.extend(trace::parse_env_trace_attributes(&attrs));
+                }
+            }
 
             let trace_protocol = trace_protocol
                 .map(|proto| proto.and_then(|p| p.parse::<CollectorProtocol>().ok()))

diff --git a/linkerd/app/src/env/trace.rs b/linkerd/app/src/env/trace.rs
@@ -14,6 +14,10 @@ pub(super) fn read_trace_attributes(path: &std::path::Path) -> HashMap<String, S
     }
 }
 
+pub(super) fn parse_env_trace_attributes(attrs: &str) -> HashMap<String, String> {
+    parse_attrs(attrs)
+}
+
 fn parse_attrs(attrs: &str) -> HashMap<String, String> {
     attrs
         .lines()

diff --git a/linkerd/app/src/trace_collector.rs b/linkerd/app/src/trace_collector.rs
@@ -1,11 +1,14 @@
-use linkerd_app_core::http_tracing::{CollectorProtocol, SpanSink};
-use linkerd_app_core::metrics::ControlHttp as HttpMetrics;
-use linkerd_app_core::svc::NewService;
-use linkerd_app_core::{control, dns, identity, opencensus, opentelemetry};
+use linkerd_app_core::{
+    control, dns,
+    http_tracing::{CollectorProtocol, SpanSink},
+    identity,
+    metrics::ControlHttp as HttpMetrics,
+    opencensus, opentelemetry,
+    svc::NewService,
+};
 use linkerd_error::Error;
-use std::collections::HashMap;
-use std::future::Future;
-use std::pin::Pin;
+use otel_collector::OtelCollectorAttributes;
+use std::{collections::HashMap, future::Future, pin::Pin};
 
 pub mod oc_collector;
 pub mod otel_collector;
@@ -92,14 +95,19 @@ impl Config {
                         svc,
                         legacy_oc_metrics,
                     ),
-                    CollectorProtocol::OpenTelemetry => otel_collector::create_collector(
-                        addr.clone(),
-                        inner.hostname,
-                        svc_name,
-                        inner.attributes,
-                        svc,
-                        legacy_otel_metrics,
-                    ),
+                    CollectorProtocol::OpenTelemetry => {
+                        let attributes = OtelCollectorAttributes {
+                            hostname: inner.hostname,
+                            service_name: svc_name,
+                            extra: inner.attributes,
+                        };
+                        otel_collector::create_collector(
+                            addr.clone(),
+                            attributes,
+                            svc,
+                            legacy_otel_metrics,
+                        )
+                    }
                 };
 
                 Ok(TraceCollector::Enabled(Box::new(collector)))

diff --git a/linkerd/app/src/trace_collector/otel_collector.rs b/linkerd/app/src/trace_collector/otel_collector.rs
@@ -4,20 +4,29 @@ use linkerd_app_core::{
 };
 use linkerd_opentelemetry::{
     self as opentelemetry, metrics,
-    proto::proto::common::v1::{any_value, AnyValue, KeyValue},
-    proto::transform::common::ResourceAttributesWithSchema,
+    proto::{
+        proto::common::v1::{any_value, AnyValue, KeyValue},
+        transform::common::ResourceAttributesWithSchema,
+    },
+};
+use std::{
+    collections::HashMap,
+    time::{SystemTime, UNIX_EPOCH},
 };
-use std::{collections::HashMap, time::SystemTime, time::UNIX_EPOCH};
 use tokio::sync::mpsc;
 use tokio_stream::wrappers::ReceiverStream;
 use tonic::{body::BoxBody, client::GrpcService};
 use tracing::Instrument;
 
+pub(super) struct OtelCollectorAttributes {
+    pub hostname: Option<String>,
+    pub service_name: String,
+    pub extra: HashMap<String, String>,
+}
+
 pub(super) fn create_collector<S>(
     addr: ControlAddr,
-    hostname: Option<String>,
-    service_name: String,
-    attributes: HashMap<String, String>,
+    attributes: OtelCollectorAttributes,
     svc: S,
     legacy_metrics: metrics::Registry,
 ) -> EnabledCollector
@@ -36,7 +45,7 @@ where
     resources
         .attributes
         .0
-        .push(service_name.with_key("service.name"));
+        .push(attributes.service_name.with_key("service.name"));
     resources
         .attributes
         .0
@@ -49,13 +58,16 @@ where
             .unwrap_or_else(|e| -(e.duration().as_secs() as i64))
             .with_key("process.start_timestamp"),
     );
-    resources
-        .attributes
-        .0
-        .push(hostname.unwrap_or_default().with_key("host.name"));
+    resources.attributes.0.push(
+        attributes
+            .hostname
+            .unwrap_or_default()
+            .with_key("host.name"),
+    );
 
     resources.attributes.0.extend(
         attributes
+            .extra
             .into_iter()
             .map(|(key, value)| value.with_key(&key)),
     );