Add OtlpMetric variant body to http generator

CHANGELOG.md

@@ -15,6 +15,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added configurable metric kind weights in OpenTelemetry metrics payload generator.
 - Added new telemetry to OpenTelemetry metrics generation: data points per
   second. This opens the door for doing the same for other payloads.
+- HTTP blackhole now supports an OtlpMetric body variant and will always respond
+  with a full success.
 
 ## [0.25.9]
 ## Added

Cargo.toml

@@ -18,6 +18,7 @@ metrics-exporter-prometheus = { version = "0.15", default-features = false, feat
   "http-listener",
   "uds-listener",
 ] }
+opentelemetry-proto = { version = "0.29", default-features = false }
 prost = "0.13"
 rand = { version = "0.9", default-features = false }
 rustc-hash = { version = "1.1" }

lading/Cargo.toml

@@ -55,6 +55,8 @@ nix = { version = "0.30", default-features = false, features = [
 num_cpus = { version = "1.16" }
 num-traits = { version = "0.2", default-features = false }
 once_cell = { workspace = true }
+opentelemetry-proto = { workspace = true, features = ["gen-tonic", "metrics"]}
+prost = { workspace = true }
 rand = { workspace = true, default-features = false, features = [
   "small_rng",
   "std",

lading/src/blackhole/http.rs

@@ -11,6 +11,8 @@ use http::{HeaderMap, header::InvalidHeaderValue, status::InvalidStatusCode};
 use http_body_util::{BodyExt, combinators::BoxBody};
 use hyper::{Request, Response, StatusCode, header};
 use metrics::counter;
+use opentelemetry_proto::tonic::collector::metrics::v1::ExportMetricsServiceResponse;
+use prost::Message;
 use serde::{Deserialize, Serialize};
 use std::{net::SocketAddr, time::Duration};
 use tracing::error;
@@ -54,6 +56,8 @@ pub enum BodyVariant {
     RawBytes,
     /// Respond with a hardcoded string value
     Static(String),
+    /// Respond with Otlp Metric Full Success, see <https://opentelemetry.io/docs/specs/otlp/#full-success-1>
+    OtlpMetric,
 }
 
 fn default_body_variant() -> BodyVariant {
@@ -210,6 +214,10 @@ impl Http {
             BodyVariant::Nothing => vec![],
             BodyVariant::RawBytes => config.raw_bytes.clone(),
             BodyVariant::Static(val) => val.as_bytes().to_vec(),
+            BodyVariant::OtlpMetric => {
+                let response = ExportMetricsServiceResponse::default();
+                response.encode_to_vec()
+            }
         };
 
         Ok(Self {

lading_payload/Cargo.toml

@@ -15,7 +15,7 @@ description = "A tool for load testing daemons."
 [dependencies]
 bytes = { workspace = true }
 byte-unit = { workspace = true, features = [] }
-opentelemetry-proto = { version = "0.29.0", features = [
+opentelemetry-proto = { workspace = true, features = [
   "trace",
   "metrics",
   "logs",