chore(tracing)!: Remove OpenCensus trace protocol

OpenCensus as a protocol has been sunset for some time now. Additionally, we have supported its replacement, OpenTelemetry, for a long time now, and we don't even expose the OpenCensus configuration from the linkerd control plane chart.

This removes OpenCensus from the proxy. There's some cleanup that will have to be done in follow-ups, but this attempts to keep the diff as minimal as possible.

Signed-off-by: Scott Fleener <[email protected]>

Author: sfleen

Cargo.lock

@@ -1374,7 +1374,6 @@ dependencies = [
  "linkerd-app-inbound",
  "linkerd-app-outbound",
  "linkerd-error",
- "linkerd-opencensus",
  "linkerd-opentelemetry",
  "linkerd-tonic-stream",
  "linkerd-workers",
@@ -1436,7 +1435,6 @@ dependencies = [
  "linkerd-meshtls",
  "linkerd-metrics",
  "linkerd-mock-http-body",
- "linkerd-opencensus",
  "linkerd-opentelemetry",
  "linkerd-proxy-api-resolve",
  "linkerd-proxy-balance",
@@ -2061,22 +2059,6 @@ dependencies = [
 name = "linkerd-opaq-route"
 version = "0.1.0"
 
-[[package]]
-name = "linkerd-opencensus"
-version = "0.1.0"
-dependencies = [
- "futures",
- "http-body",
- "linkerd-error",
- "linkerd-metrics",
- "linkerd-trace-context",
- "opencensus-proto",
- "tokio",
- "tokio-stream",
- "tonic",
- "tracing",
-]
-
 [[package]]
 name = "linkerd-opentelemetry"
 version = "0.1.0"
@@ -2930,16 +2912,6 @@ dependencies = [
  "portable-atomic",
 ]
 
-[[package]]
-name = "opencensus-proto"
-version = "0.1.0"
-dependencies = [
- "prost 0.13.5",
- "prost-types 0.13.5",
- "tonic",
- "tonic-build",
-]
-
 [[package]]
 name = "opentelemetry"
 version = "0.30.0"

Cargo.toml

@@ -46,7 +46,6 @@ members = [
     "linkerd/metrics",
     "linkerd/mock/http-body",
     "linkerd/opaq-route",
-    "linkerd/opencensus",
     "linkerd/opentelemetry",
     "linkerd/pool",
     "linkerd/pool/mock",
@@ -85,7 +84,6 @@ members = [
     "linkerd/transport-metrics",
     "linkerd/workers",
     "linkerd2-proxy",
-    "opencensus-proto",
     "spiffe-proto",
     "tools",
 ]

linkerd/app/Cargo.toml

@@ -25,7 +25,6 @@ linkerd-app-gateway = { path = "./gateway" }
 linkerd-app-inbound = { path = "./inbound" }
 linkerd-app-outbound = { path = "./outbound" }
 linkerd-error = { path = "../error" }
-linkerd-opencensus = { path = "../opencensus" }
 linkerd-opentelemetry = { path = "../opentelemetry" }
 linkerd-tonic-stream = { path = "../tonic-stream" }
 linkerd-workers = { path = "../workers" }

linkerd/app/core/Cargo.toml

@@ -39,7 +39,6 @@ linkerd-idle-cache = { path = "../../idle-cache" }
 linkerd-io = { path = "../../io" }
 linkerd-meshtls = { path = "../../meshtls", default-features = false }
 linkerd-metrics = { path = "../../metrics", features = ["process", "stack"] }
-linkerd-opencensus = { path = "../../opencensus" }
 linkerd-opentelemetry = { path = "../../opentelemetry" }
 linkerd-proxy-api-resolve = { path = "../../proxy/api-resolve" }
 linkerd-proxy-balance = { path = "../../proxy/balance" }

linkerd/app/core/src/http_tracing.rs

@@ -11,17 +11,14 @@ use tokio::sync::mpsc;
 #[derive(Debug, Copy, Clone, Default)]
 pub enum CollectorProtocol {
     #[default]
-    OpenCensus,
     OpenTelemetry,
 }
 
 impl FromStr for CollectorProtocol {
     type Err = ();
 
     fn from_str(s: &str) -> Result<Self, Self::Err> {
-        if s.eq_ignore_ascii_case("opencensus") {
-            Ok(Self::OpenCensus)
-        } else if s.eq_ignore_ascii_case("opentelemetry") {
+        if s.eq_ignore_ascii_case("opentelemetry") {
             Ok(Self::OpenTelemetry)
         } else {
             Err(())

linkerd/app/core/src/lib.rs

@@ -39,7 +39,6 @@ pub use linkerd_exp_backoff as exp_backoff;
 pub use linkerd_http_metrics as http_metrics;
 pub use linkerd_idle_cache as idle_cache;
 pub use linkerd_io as io;
-pub use linkerd_opencensus as opencensus;
 pub use linkerd_opentelemetry as opentelemetry;
 pub use linkerd_service_profiles as profiles;
 pub use linkerd_stack_metrics as stack_metrics;

linkerd/app/core/src/metrics.rs

@@ -9,7 +9,7 @@
 pub use crate::transport::labels::{TargetAddr, TlsAccept};
 use crate::{
     classify::Class,
-    control, http_metrics, opencensus, opentelemetry, profiles, proxy, stack_metrics, svc, tls,
+    control, http_metrics, opentelemetry, profiles, proxy, stack_metrics, svc, tls,
     transport::{self, labels::TlsConnect},
 };
 use linkerd_addr::Addr;
@@ -37,7 +37,6 @@ pub type Stack = stack_metrics::Registry<StackLabels>;
 pub struct Metrics {
     pub proxy: Proxy,
     pub control: ControlHttp,
-    pub opencensus: opencensus::metrics::Registry,
     pub opentelemetry: opentelemetry::metrics::Registry,
 }
 
@@ -213,13 +212,11 @@ impl Metrics {
             transport,
         };
 
-        let (opencensus, opencensus_report) = opencensus::metrics::new();
         let (opentelemetry, opentelemetry_report) = opentelemetry::metrics::new();
 
         let metrics = Metrics {
             proxy,
             control,
-            opencensus,
             opentelemetry,
         };
 
@@ -230,7 +227,6 @@ impl Metrics {
             .and_report(actual_report)
             .and_report(control_report)
             .and_report(transport_report)
-            .and_report(opencensus_report)
             .and_report(opentelemetry_report)
             .and_report(stack);
 

linkerd/app/src/lib.rs

@@ -206,16 +206,8 @@ impl Config {
             let dns = dns.resolver("trace_collector");
             let client_metrics = metrics.control.clone();
             let otel_metrics = metrics.opentelemetry;
-            let oc_metrics = metrics.opencensus;
             info_span!("tracing").in_scope(|| {
-                trace_collector.build(
-                    identity,
-                    dns,
-                    oc_metrics,
-                    otel_metrics,
-                    control_metrics,
-                    client_metrics,
-                )
+                trace_collector.build(identity, dns, otel_metrics, control_metrics, client_metrics)
             })
         }?;
 

linkerd/app/src/trace_collector.rs

@@ -3,14 +3,13 @@ use linkerd_app_core::{
     http_tracing::{CollectorProtocol, SpanSink},
     identity,
     metrics::ControlHttp as HttpMetrics,
-    opencensus, opentelemetry,
+    opentelemetry,
     svc::NewService,
 };
 use linkerd_error::Error;
 use otel_collector::OtelCollectorAttributes;
 use std::{collections::HashMap, future::Future, pin::Pin};
 
-pub mod oc_collector;
 pub mod otel_collector;
 
 const SPAN_BUFFER_CAPACITY: usize = 100;
@@ -59,7 +58,6 @@ impl Config {
         match self {
             Config::Disabled => None,
             Config::Enabled(config) => match config.kind {
-                CollectorProtocol::OpenCensus => Some("opencensus"),
                 CollectorProtocol::OpenTelemetry => Some("opentelemetry"),
             },
         }
@@ -69,7 +67,6 @@ impl Config {
         self,
         identity: identity::NewClient,
         dns: dns::Resolver,
-        legacy_oc_metrics: opencensus::metrics::Registry,
         legacy_otel_metrics: opentelemetry::metrics::Registry,
         control_metrics: control::Metrics,
         client_metrics: HttpMetrics,
@@ -87,14 +84,6 @@ impl Config {
                     .unwrap_or_else(|| SERVICE_NAME.to_string());
 
                 let collector = match inner.kind {
-                    CollectorProtocol::OpenCensus => oc_collector::create_collector(
-                        addr.clone(),
-                        inner.hostname,
-                        svc_name,
-                        inner.attributes,
-                        svc,
-                        legacy_oc_metrics,
-                    ),
                     CollectorProtocol::OpenTelemetry => {
                         let attributes = OtelCollectorAttributes {
                             hostname: inner.hostname,