chore: add load test to example-axum-otlp to monitor memory leak

Author: davidB

.mise.toml

@@ -12,6 +12,7 @@ rust = '1.80.0'
 just = '1'
 grpcurl = '1.9'
 protoc = '29.2'
+k6 = '0.43'
 # grpc-health-probe = "*"
 # sccache = "0.5"
 "aqua:cargo-bins/cargo-binstall" = "1" # do not use cargo-binstall (it's a special name used by mise)

examples/axum-otlp/Cargo.toml

@@ -14,6 +14,7 @@ init-tracing-opentelemetry = { path = "../../init-tracing-opentelemetry", featur
   "otlp",
   "tracing_subscriber_ext",
 ] }
+memory-stats = "1.1"
 opentelemetry = { workspace = true }
 opentelemetry-otlp = { workspace = true, default-features = false, features = [
   "reqwest-rustls",

examples/axum-otlp/README.md

@@ -77,5 +77,28 @@ content-type: application/json
 content-length: 15
 date: Wed, 28 Dec 2022 17:14:07 GMT
 
-{"status":"UP"}
+{"physical_mem":16056320,"status":"UP","virtual_mem":1130790912}
 ```
+
+## Load test
+
+on terminal 1: launch the server: `just run_example_axum-otlp_server`
+on terminal 2: periodically print the memory usage: `just run_example_axum-otlp_load_client`
+on terminal 3: launch the load test script `just run_example_axum-otlp_load`
+
+```txt
+...
+{"physical_mem":16633856,"status":"UP","virtual_mem":1130790912}
+{"physical_mem":16633856,"status":"UP","virtual_mem":1130790912}
+{"physical_mem":18382848,"status":"UP","virtual_mem":1130790912}
+{"physical_mem":19562496,"status":"UP","virtual_mem":1130790912}
+{"physical_mem":19689472,"status":"UP","virtual_mem":1130790912}
+{"physical_mem":20312064,"status":"UP","virtual_mem":1130790912}
+{"physical_mem":20529152,"status":"UP","virtual_mem":1130790912}
+{"physical_mem":21012480,"status":"UP","virtual_mem":1130790912}
+{"physical_mem":21258240,"status":"UP","virtual_mem":1130790912}
+{"physical_mem":21286912,"status":"UP","virtual_mem":1130790912}
+...
+```
+
+Alternatively, you can use the `examples/load`.

examples/axum-otlp/k6-script.js

@@ -0,0 +1,59 @@
+import { sleep } from "k6";
+import http from "k6/http";
+
+export const options = {
+  // A number specifying the number of VUs to run concurrently.
+  vus: 10,
+  // A string specifying the total duration of the test run.
+  duration: "120s",
+
+  // The following section contains configuration options for execution of this
+  // test script in Grafana Cloud.
+  //
+  // See https://grafana.com/docs/grafana-cloud/k6/get-started/run-cloud-tests-from-the-cli/
+  // to learn about authoring and running k6 test scripts in Grafana k6 Cloud.
+  //
+  // cloud: {
+  //   // The ID of the project to which the test is assigned in the k6 Cloud UI.
+  //   // By default tests are executed in default project.
+  //   projectID: "",
+  //   // The name of the test in the k6 Cloud UI.
+  //   // Test runs with the same name will be grouped.
+  //   name: "script.js"
+  // },
+
+  // Uncomment this section to enable the use of Browser API in your tests.
+  //
+  // See https://grafana.com/docs/k6/latest/using-k6-browser/running-browser-tests/ to learn more
+  // about using Browser API in your test scripts.
+  //
+  // scenarios: {
+  //   // The scenario name appears in the result summary, tags, and so on.
+  //   // You can give the scenario any name, as long as each name in the script is unique.
+  //   ui: {
+  //     // Executor is a mandatory parameter for browser-based tests.
+  //     // Shared iterations in this case tells k6 to reuse VUs to execute iterations.
+  //     //
+  //     // See https://grafana.com/docs/k6/latest/using-k6/scenarios/executors/ for other executor types.
+  //     executor: 'shared-iterations',
+  //     options: {
+  //       browser: {
+  //         // This is a mandatory parameter that instructs k6 to launch and
+  //         // connect to a chromium-based browser, and use it to run UI-based
+  //         // tests.
+  //         type: 'chromium',
+  //       },
+  //     },
+  //   },
+  // }
+};
+
+// The function that defines VU logic.
+//
+// See https://grafana.com/docs/k6/latest/examples/get-started-with-k6/ to learn more
+// about authoring k6 scripts.
+//
+export default function () {
+  http.get("http://127.0.0.1:3003/");
+  sleep(0.2);
+}

examples/axum-otlp/src/main.rs

@@ -28,7 +28,7 @@ fn app() -> Router {
     // build our application with a route
     Router::new()
         .route(
-            "/proxy/:service/*path",
+            "/proxy/{service}/{*path}",
             get(proxy_handler).post(proxy_handler),
         )
         .route("/", get(index)) // request processed inside span
@@ -40,7 +40,10 @@ fn app() -> Router {
 }
 
 async fn health() -> impl IntoResponse {
-    axum::Json(json!({ "status" : "UP" }))
+    let memory_stats = memory_stats::memory_stats();
+    axum::Json(
+        json!({ "status" : "UP", "physical_mem": memory_stats.map(|s| s.physical_mem), "virtual_mem": memory_stats.map(|s| s.virtual_mem) }),
+    )
 }
 
 #[tracing::instrument]

justfile

@@ -126,3 +126,9 @@ run_example_http_client:
 
 run_example_load:
     cd examples/load; cargo run --release 2>/dev/null
+
+run_example_axum-otlp_load:
+    cd examples/axum-otlp; k6 run k6-script.js
+
+run_example_axum-otlp_load_client:
+    while true; do curl -S http://127.0.0.1:3003/health; echo ""; sleep 3; done