Add http-instrumentation-tempo

lib/http-instrumentation-tempo/1.0.0/index.js

@@ -0,0 +1,199 @@
+// This code specifically uses commonJS as to be faster loading in k6
+// this can be changed after https://github.com/grafana/k6/issues/3265
+const http = require("k6/http");
+const crypto = require("k6/crypto");
+const execution = require("k6/execution");
+
+// saving the original values
+const request = http.request;
+const asyncRequest = http.asyncRequest;
+
+const propagatorMap = {
+  "w3c": (sampler, traceID) => {
+    return {
+      "traceparent": `00-${traceID}-${randHexString(16)}-${sampler() ? "01" : "00"}`
+    }
+  },
+  "jaeger": (sampler, traceID) => {
+    return {
+      "uber-trace-id": `${traceID}:${randHexString(8)}:0:${sampler() ? "1" : "0"}`,
+    }
+  },
+}
+
+class Client {
+  #propagator;
+  #sampler;
+
+  constructor(opts) {
+    this.configure(opts)
+  }
+
+  configure(opts) {
+    this.#sampler = newProbalisticSampler(opts.sampling);
+    this.#propagator = propagatorMap[opts.propagator];
+    if (this.#propagator == null) {
+      throw "unknown propagator: " + opts.propagator
+    }
+  }
+
+  // request instruments the http module's request function with tracing headers,
+  // and ensures the trace_id is emitted as part of the output's data points metadata.
+  request(method, url, ...args) {
+    const traceID = newTraceID()
+    const traceContextHeader = this.#propagator(this.#sampler, traceID)
+    args = instrumentArguments(traceContextHeader, ...args)
+
+    try {
+      execution.vu.metrics.metadata["trace_id"] = traceID
+      return request(method, url, ...args)
+    } finally {
+      delete execution.vu.metrics.metadata["trace_id"]
+
+    }
+  }
+
+  // asyncRequest instruments the http module's asyncRequest function with tracing headers,
+  // and ensures the trace_id is emitted as part of the output's data points metadata.
+  async asyncRequest(method, url, ...args) {
+    const traceID = newTraceID()
+    const traceContextHeader = this.#propagator(this.#sampler, traceID)
+    args = instrumentArguments(traceContextHeader, ...args)
+
+    let promise;
+    try {
+      execution.vu.metrics.metadata["trace_id"] = traceID
+      promise = asyncRequest(method, url, ...args)
+    } finally {
+      delete execution.vu.metrics.metadata["trace_id"]
+    }
+
+    return await promise;
+  }
+
+  del(url, ...args) { return this.request("DELETE", url, ...args) }
+  get(url, ...args) { return this.request("GET", url, null, ...args) }
+  head(url, ...args) { return this.request("HEAD", url, null, ...args) }
+  options(url, ...args) { return this.request("OPTIONS", url, ...args) }
+  patch(url, ...args) { return this.request("PATCH", url, ...args) }
+  post(url, ...args) { return this.request("POST", url, ...args) }
+  put(url, ...args) { return this.request("PUT", url, ...args) }
+}
+
+function longToByteArray(long) {
+  var byteArray = new Uint8Array(8)
+
+  for (var index = byteArray.byteLength; index >= 0; index--) {
+    const byte = long % 256
+    byteArray[index] = byte
+    long = (long-byte)/256;
+    if (long < 1) {
+      break
+    }
+  }
+
+  return byteArray;
+}
+function instrumentArguments(traceContext, ...args) {
+  switch (args.length) {
+    case 0:
+      args.push(null)
+    // fallthrough to add the header
+    case 1:
+      // We only received a body argument
+      args.push({ headers: traceContext })
+      break;
+    default: // this handles 2 and more just in case someone provided more arguments
+      // We received both a body and a params argument. In the
+      // event params would be nullish, we'll instantiate
+      // a new object.
+      if (args[1] == null) args[1] = {}
+
+      let params = args[1]
+      if (params.headers == null) {
+        params.headers = {}
+      }
+      Object.assign(params.headers, traceContext)
+      break;
+  }
+
+  return args
+}
+
+
+function newTraceID() {
+  let result = "dc0718" // prefix for k6
+
+  // add nanoseconds
+  let now = Date.now()
+  const ns = longToByteArray(now * 1e6) // this is very likely ... loosy
+  let n = 3
+  let i = 0
+  for (; i < ns.byteLength; i++) { // skip leading zeros
+    if (ns[i] == 0) continue;
+    break;
+  }
+  for (; i < ns.byteLength; i++) {
+    result += ns[i].toString(16).padStart(2, "0")
+    n++;
+  }
+
+  // pad with random
+  let random = new Uint8Array(crypto.randomBytes(16 - n));
+  for (i=0; i < random.byteLength; i++) {
+    result += random[i].toString(16).padStart(2, "0")
+    n++;
+  }
+
+  return result
+}
+
+function newProbalisticSampler(samplingRate) {
+  if (samplingRate < 0 || samplingRate > 1) {
+    throw "sampling rate must be between 0.0 and 1.0"
+  }
+  if (typeof samplingRate == 'undefined') {
+    samplingRate = 1
+
+  }
+  switch (samplingRate) {
+    case 0:
+      return () => false
+    case 1:
+      return () => true
+    default:
+      return () => Math.random() < samplingRate
+  }
+}
+
+const digits = "0123456789abcdef";
+
+function randHexString(n) {
+  let result = '';
+  for (let i = 0; i < n; ++i) {
+    result += digits[Math.floor(16 * Math.random())];
+  }
+  return result;
+}
+
+function instrumentHTTP(opts) {
+  const client = new Client(opts)
+
+  http.del = client.del.bind(client);
+  http.get = client.get.bind(client);
+  http.head = client.head.bind(client);
+  http.options = client.options.bind(client);
+  http.patch = client.patch.bind(client);
+  http.post = client.post.bind(client);
+  http.put = client.put.bind(client);
+  http.request = client.request.bind(client)
+  http.asyncRequest = client.asyncRequest.bind(client)
+}
+
+const exp = { Client: Client, instrumentHTTP: instrumentHTTP };
+
+module.exports = {
+  default: exp,
+  __esModule: true,
+  ...exp
+}

lib/index.html

@@ -634,6 +634,10 @@ <h2>Available libs</h2>
       <td>http-instrumentation-pyroscope</td>
       <td><a target="_blank" href="https://jslib.k6.io/http-instrumentation-pyroscope/1.0.0/index.js">1.0.0</a></td>
       <td><a href="https://grafana.com/docs/k6/latest/javascript-api/jslib/http-instrumentation-pyroscope/">https://grafana.com/docs/k6/latest/javascript-api/jslib/http-instrumentation-pyroscope/</a></td>
+    </tr><tr>
+      <td>http-instrumentation-tempo</td>
+      <td><a target="_blank" href="https://jslib.k6.io/http-instrumentation-tempo/1.0.0/index.js">1.0.0</a></td>
+      <td><a href="https://grafana.com/docs/k6/latest/javascript-api/jslib/http-instrumentation-tempo/">https://grafana.com/docs/k6/latest/javascript-api/jslib/http-instrumentation-tempo/</a></td>
     </tr>
     </table>
 

supported.json

@@ -75,5 +75,11 @@
       "1.0.0"
     ],
     "docs-url": "https://grafana.com/docs/k6/latest/javascript-api/jslib/http-instrumentation-pyroscope/"
+  },
+  "http-instrumentation-tempo": {
+    "versions": [
+      "1.0.0"
+    ],
+    "docs-url": "https://grafana.com/docs/k6/latest/javascript-api/jslib/http-instrumentation-tempo/"
   }
 }

tests/basic.js

@@ -22,6 +22,7 @@ import {
 } from '../lib/k6-utils/1.4.0/index.js'
 
 import pyroscope from "../lib/http-instrumentation-pyroscope/1.0.0/index.js"
+import tempo from "../lib/http-instrumentation-tempo/1.0.0/index.js"
 
 initContractPlugin(chai)