Switch to opentelemetry-prometheus-text-exporter

2025-08-18 11:28:55 +02:00
parent d7691b9b02
commit 4578debdc2
5 changed files with 49 additions and 84 deletions
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3191,12 +3191,11 @@ dependencies = [
 "opentelemetry-http",
 "opentelemetry-jaeger-propagator",
 "opentelemetry-otlp",
- "opentelemetry-prometheus",
+ "opentelemetry-prometheus-text-exporter",
 "opentelemetry-resource-detectors",
 "opentelemetry-semantic-conventions",
 "opentelemetry-stdout",
 "opentelemetry_sdk",
- "prometheus",
 "rand 0.8.5",
 "rand_chacha 0.3.1",
 "reqwest",
@@ -4172,15 +4171,14 @@ dependencies = [
 ]

 [[package]]
-name = "opentelemetry-prometheus"
-version = "0.29.1"
-source = "git+https://github.com/sandhose/opentelemetry-rust.git?branch=otel-prometheus-0.30#193906c7577b4f8ee642aa771191c7d80b14a297"
+name = "opentelemetry-prometheus-text-exporter"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ddbb5743c13741bd9207de7c449f9797c0e513ac07551eac807da94056c530d9"
 dependencies = [
- "once_cell",
 "opentelemetry",
 "opentelemetry_sdk",
- "prometheus",
- "tracing",
+ "smartstring",
 ]

 [[package]]
@@ -4671,21 +4669,6 @@ dependencies = [
 "yansi",
 ]

-[[package]]
-name = "prometheus"
-version = "0.14.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3ca5326d8d0b950a9acd87e6a3f94745394f62e4dae1b1ee22b2bc0c394af43a"
-dependencies = [
- "cfg-if",
- "fnv",
- "lazy_static",
- "memchr",
- "parking_lot",
- "protobuf",
- "thiserror 2.0.12",
-]
-
 [[package]]
 name = "prost"
 version = "0.13.5"
@@ -4709,26 +4692,6 @@ dependencies = [
 "syn",
 ]

-[[package]]
-name = "protobuf"
-version = "3.7.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d65a1d4ddae7d8b5de68153b48f6aa3bba8cb002b243dbdbc55a5afbc98f99f4"
-dependencies = [
- "once_cell",
- "protobuf-support",
- "thiserror 1.0.69",
-]
-
-[[package]]
-name = "protobuf-support"
-version = "3.7.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3e36c2f31e0a47f9280fb347ef5e461ffcd2c52dd520d8e216b52f93b0b0d7d6"
-dependencies = [
- "thiserror 1.0.69",
-]
-
 [[package]]
 name = "psl"
 version = "2.1.128"
@@ -5830,6 +5793,17 @@ dependencies = [
 "serde",
 ]

+[[package]]
+name = "smartstring"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3fb72c633efbaa2dd666986505016c32c3044395ceaf881518399d2f4127ee29"
+dependencies = [
+ "autocfg",
+ "static_assertions",
+ "version_check",
+]
+
 [[package]]
 name = "socket2"
 version = "0.6.0"
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -407,10 +407,8 @@ version = "0.30.0"
 version = "0.30.0"
 default-features = false
 features = ["trace", "metrics", "http-proto"]
-[workspace.dependencies.opentelemetry-prometheus]
-# https://github.com/open-telemetry/opentelemetry-rust/pull/3076
-git = "https://github.com/sandhose/opentelemetry-rust.git"
-branch = "otel-prometheus-0.30"
+[workspace.dependencies.opentelemetry-prometheus-text-exporter]
+version = "0.2.0"
 [workspace.dependencies.opentelemetry-resource-detectors]
 version = "0.9.0"
 [workspace.dependencies.opentelemetry-semantic-conventions]
@@ -480,10 +478,6 @@ features = ["std", "pkcs5", "encryption"]
 [workspace.dependencies.psl]
 version = "2.1.128"

-# Prometheus metrics
-[workspace.dependencies.prometheus]
-version = "0.14.0"
-
 # High-precision clock
 [workspace.dependencies.quanta]
 version = "0.12.6"
--- a/crates/cli/Cargo.toml
+++ b/crates/cli/Cargo.toml
@@ -59,12 +59,11 @@ opentelemetry.workspace = true
 opentelemetry-http.workspace = true
 opentelemetry-jaeger-propagator.workspace = true
 opentelemetry-otlp.workspace = true
-opentelemetry-prometheus.workspace = true
+opentelemetry-prometheus-text-exporter.workspace = true
 opentelemetry-resource-detectors.workspace = true
 opentelemetry-semantic-conventions.workspace = true
 opentelemetry-stdout.workspace = true
 opentelemetry_sdk.workspace = true
-prometheus.workspace = true
 sentry.workspace = true
 sentry-tracing.workspace = true
 sentry-tower.workspace = true
--- a/crates/cli/src/telemetry.rs
+++ b/crates/cli/src/telemetry.rs
@@ -23,7 +23,7 @@ use opentelemetry::{
    trace::TracerProvider as _,
 };
 use opentelemetry_otlp::{WithExportConfig, WithHttpConfig};
-use opentelemetry_prometheus::PrometheusExporter;
+use opentelemetry_prometheus_text_exporter::PrometheusExporter;
 use opentelemetry_sdk::{
    Resource,
    metrics::{ManualReader, SdkMeterProvider, periodic_reader_with_async_runtime::PeriodicReader},
@@ -33,7 +33,6 @@ use opentelemetry_sdk::{
    },
 };
 use opentelemetry_semantic_conventions as semcov;
-use prometheus::Registry;
 use url::Url;

 static SCOPE: LazyLock<InstrumentationScope> = LazyLock::new(|| {
@@ -49,7 +48,7 @@ pub static METER: LazyLock<Meter> =
 pub static TRACER: OnceLock<Tracer> = OnceLock::new();
 static METER_PROVIDER: OnceLock<SdkMeterProvider> = OnceLock::new();
 static TRACER_PROVIDER: OnceLock<SdkTracerProvider> = OnceLock::new();
-static PROMETHEUS_REGISTRY: OnceLock<Registry> = OnceLock::new();
+static PROMETHEUS_EXPORTER: OnceLock<PrometheusExporter> = OnceLock::new();

 pub fn setup(config: &TelemetryConfig) -> anyhow::Result<()> {
    let propagator = propagator(&config.tracing.propagators);
@@ -180,21 +179,30 @@ type PromServiceFuture =

 #[allow(clippy::needless_pass_by_value)]
 fn prometheus_service_fn<T>(_req: T) -> PromServiceFuture {
-    use prometheus::{Encoder, TextEncoder};
+    let response = if let Some(exporter) = PROMETHEUS_EXPORTER.get() {
+        // We'll need some space for this, so we preallocate a bit
+        let mut buffer = Vec::with_capacity(1024);

-    let response = if let Some(registry) = PROMETHEUS_REGISTRY.get() {
-        let mut buffer = Vec::new();
-        let encoder = TextEncoder::new();
-        let metric_families = registry.gather();
+        if let Err(err) = exporter.export(&mut buffer) {
+            tracing::error!(
+                error = &err as &dyn std::error::Error,
+                "Failed to export Prometheus metrics"
+            );

-        // That shouldn't panic, unless we're constructing invalid labels
-        encoder.encode(&metric_families, &mut buffer).unwrap();
-
-        Response::builder()
-            .status(200)
-            .header(CONTENT_TYPE, encoder.format_type())
-            .body(Full::new(Bytes::from(buffer)))
-            .unwrap()
+            Response::builder()
+                .status(500)
+                .header(CONTENT_TYPE, "text/plain")
+                .body(Full::new(Bytes::from_static(
+                    b"Failed to export Prometheus metrics, see logs for details",
+                )))
+                .unwrap()
+        } else {
+            Response::builder()
+                .status(200)
+                .header(CONTENT_TYPE, "text/plain;version=1.0.0")
+                .body(Full::new(Bytes::from(buffer)))
+                .unwrap()
+        }
    } else {
        Response::builder()
            .status(500)
@@ -209,7 +217,7 @@ fn prometheus_service_fn<T>(_req: T) -> PromServiceFuture {
 }

 pub fn prometheus_service<T>() -> tower::util::ServiceFn<fn(T) -> PromServiceFuture> {
-    if PROMETHEUS_REGISTRY.get().is_none() {
+    if PROMETHEUS_EXPORTER.get().is_none() {
        tracing::warn!(
            "A Prometheus resource was mounted on a listener, but the Prometheus exporter was not setup in the config"
        );
@@ -219,16 +227,11 @@ pub fn prometheus_service<T>() -> tower::util::ServiceFn<fn(T) -> PromServiceFut
 }

 fn prometheus_metric_reader() -> anyhow::Result<PrometheusExporter> {
-    let registry = Registry::new();
+    let exporter = PrometheusExporter::builder().without_scope_info().build();

-    PROMETHEUS_REGISTRY
-        .set(registry.clone())
-        .map_err(|_| anyhow::anyhow!("PROMETHEUS_REGISTRY was set twice"))?;
-
-    let exporter = opentelemetry_prometheus::exporter()
-        .with_registry(registry)
-        .without_scope_info()
-        .build()?;
+    PROMETHEUS_EXPORTER
+        .set(exporter.clone())
+        .map_err(|_| anyhow::anyhow!("PROMETHEUS_EXPORTER was set twice"))?;

    Ok(exporter)
 }
--- a/deny.toml
+++ b/deny.toml
@@ -98,8 +98,3 @@ deny = ["oldtime"]
 unknown-registry = "warn"
 unknown-git = "warn"
 allow-registry = ["https://github.com/rust-lang/crates.io-index"]
-
-allow-git = [
-    # https://github.com/open-telemetry/opentelemetry-rust/pull/3076
-    "https://github.com/sandhose/opentelemetry-rust",
-]