chore(tracing): Remove OpenCensus remnants

There were a few abstractions over the trace backend (enums, etc.) that can be removed now that OpenCensus has been removed in #4216.

Signed-off-by: Scott Fleener <scott@buoyant.io>

Author: sfleen

Cargo.lock

@@ -4019,13 +4019,6 @@ dependencies = [
  "syn",
 ]
 
-[[package]]
-name = "tools"
-version = "0.1.0"
-dependencies = [
- "tonic-build",
-]
-
 [[package]]
 name = "tower"
 version = "0.5.2"

linkerd/app/core/src/http_tracing.rs

@@ -5,27 +5,9 @@ use linkerd_trace_context::{
     export::{ExportSpan, SpanKind, SpanLabels},
     Span, TraceContext,
 };
-use std::{str::FromStr, sync::Arc};
+use std::sync::Arc;
 use tokio::sync::mpsc;
 
-#[derive(Debug, Copy, Clone, Default)]
-pub enum CollectorProtocol {
-    #[default]
-    OpenTelemetry,
-}
-
-impl FromStr for CollectorProtocol {
-    type Err = ();
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        if s.eq_ignore_ascii_case("opentelemetry") {
-            Ok(Self::OpenTelemetry)
-        } else {
-            Err(())
-        }
-    }
-}
-
 pub type SpanSink = mpsc::Sender<ExportSpan>;
 
 pub fn server<S>(

linkerd/app/src/env.rs

@@ -3,7 +3,6 @@ use linkerd_app_core::{
     addr,
     config::*,
     control::{Config as ControlConfig, ControlAddr},
-    http_tracing::CollectorProtocol,
     proxy::http::{h1, h2},
     tls,
     transport::{DualListenAddr, Keepalive, ListenAddr, UserTimeout},
@@ -155,7 +154,6 @@ const ENV_INBOUND_METRICS_AUTHORITY_LABELS: &str =
     "LINKERD2_PROXY_INBOUND_METRICS_AUTHORITY_LABELS";
 
 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";
 // This doesn't have the LINKERD2_ prefix because it is a conventional env var from OpenTelemetry:
@@ -445,7 +443,6 @@ pub fn parse_config<S: Strings>(strings: &S) -> Result<super::Config, EnvError>
     let trace_attributes_file_path = strings.get(ENV_TRACE_ATTRIBUTES_PATH);
     let trace_extra_attributes = strings.get(ENV_TRACE_EXTRA_ATTRIBUTES);
     let trace_otel_attributes = strings.get(ENV_OTEL_TRACE_ATTRIBUTES);
-    let trace_protocol = strings.get(ENV_TRACE_PROTOCOL);
     let trace_service_name = strings.get(ENV_TRACE_SERVICE_NAME);
 
     let trace_collector_addr = parse_control_addr(strings, ENV_TRACE_COLLECTOR_SVC_BASE);
@@ -873,12 +870,6 @@ pub fn parse_config<S: Strings>(strings: &S) -> Result<super::Config, EnvError>
                 }
             }
 
-            let trace_protocol = trace_protocol
-                .map(|proto| proto.and_then(|p| p.parse::<CollectorProtocol>().ok()))
-                .ok()
-                .flatten()
-                .unwrap_or_default();
-
             let trace_service_name = trace_service_name.ok().flatten();
 
             trace_collector::Config::Enabled(Box::new(trace_collector::EnabledConfig {
@@ -893,7 +884,6 @@ pub fn parse_config<S: Strings>(strings: &S) -> Result<super::Config, EnvError>
                         failfast_timeout,
                     },
                 },
-                kind: trace_protocol,
             }))
         }
     };

linkerd/app/src/trace_collector.rs

@@ -1,10 +1,6 @@
 use linkerd_app_core::{
-    control, dns,
-    http_tracing::{CollectorProtocol, SpanSink},
-    identity,
-    metrics::ControlHttp as HttpMetrics,
-    opentelemetry,
-    svc::NewService,
+    control, dns, http_tracing::SpanSink, identity, metrics::ControlHttp as HttpMetrics,
+    opentelemetry, svc::NewService,
 };
 use linkerd_error::Error;
 use otel_collector::OtelCollectorAttributes;
@@ -27,7 +23,6 @@ pub struct EnabledConfig {
     pub attributes: HashMap<String, String>,
     pub hostname: Option<String>,
     pub service_name: Option<String>,
-    pub kind: CollectorProtocol,
 }
 
 pub type Task = Pin<Box<dyn Future<Output = ()> + Send + 'static>>;
@@ -39,7 +34,6 @@ pub enum TraceCollector {
 
 pub struct EnabledCollector {
     pub addr: control::ControlAddr,
-    pub kind: CollectorProtocol,
     pub span_sink: SpanSink,
     pub task: Task,
 }
@@ -57,9 +51,7 @@ impl Config {
     pub fn metrics_prefix(&self) -> Option<&'static str> {
         match self {
             Config::Disabled => None,
-            Config::Enabled(config) => match config.kind {
-                CollectorProtocol::OpenTelemetry => Some("opentelemetry"),
-            },
+            Config::Enabled(_) => Some("opentelemetry"),
         }
     }
 
@@ -83,20 +75,18 @@ impl Config {
                     .service_name
                     .unwrap_or_else(|| SERVICE_NAME.to_string());
 
-                let collector = match inner.kind {
-                    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,
-                        )
-                    }
+                let collector = {
+                    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)))

linkerd/app/src/trace_collector/otel_collector.rs

@@ -1,7 +1,5 @@
 use super::EnabledCollector;
-use linkerd_app_core::{
-    control::ControlAddr, http_tracing::CollectorProtocol, proxy::http::Body, Error,
-};
+use linkerd_app_core::{control::ControlAddr, proxy::http::Body, Error};
 use linkerd_opentelemetry::{
     self as opentelemetry, metrics,
     proto::{
@@ -82,7 +80,6 @@ where
         addr,
         task,
         span_sink,
-        kind: CollectorProtocol::OpenTelemetry,
     }
 }