feat(users/Profpatsch): start dbus tracer nodejs client lib

We want to use the tracers quite similar to how we’d use OTEL for
tracing, meaning you should be able to start a span and use it within
another span to register it as a parent span.

They are also batched up and sent asynchrously, so the won’t incur a
lot of overhead on dbus nor block the main execution flow (done via
sending a nodejs event and a dedicated batch sending process).

Change-Id: If61b85305807e661ffee386f793c11c4b7a858a9
Reviewed-on: https://cl.tvl.fyi/c/depot/+/12888
Reviewed-by: Profpatsch <mail@profpatsch.de>
Tested-by: BuildkiteCI
This commit is contained in:
Profpatsch 2024-12-13 19:54:46 +01:00
parent c12fdeb8e0
commit b8fd86a53e

View file

@ -1,3 +1,4 @@
'use strict';
//@ts-check
// Step 3: Create the script
@ -17,6 +18,7 @@ const { AsyncHooksContextManager } = require('@opentelemetry/context-async-hooks
const { EventEmitter } = require('stream');
const { setTimeout } = require('node:timers/promises');
const { promisify } = require('util');
const { randomUUID, randomBytes, pseudoRandomBytes } = require('crypto');
// NB: this code is like 80% copilot generated, and seriously missing error handling.
// It might break at any time, but for now it seems to work lol.
@ -51,16 +53,23 @@ class Bus {
this._bus = dbus.systemBus();
break;
}
this._bus.connection.once('error', err => {
console.error(`${this._type} bus ${this._name} error: ${err}`);
throw new Error(`${this._type} bus ${this._name} error: ${err}`);
});
this._bus.connection.once(
'error',
/** @param {Error} err */
err => {
console.error(`${this._type} bus ${this._name} error: ${err}`);
throw new Error(`${this._type} bus ${this._name} error: ${err}`);
},
);
this._bus.connection.once('end', () => {
console.error(`${this._type} bus ${this._name} connection ended unexpectedly`);
throw new Error(`${this._type} bus ${this._name} connection ended unexpectedly`);
});
}
/**
* @param {string} what
*/
_busErrorMessages(what) {
return `Error getting ${what} from ${this._type} bus ${this._name}`;
}
@ -122,11 +131,12 @@ class Bus {
// We need to promisify all methods on the interface
const methodNames = Object.keys(iface.$methods ?? {});
/** @type {{[key: string]: any}} */
const methods = {};
/** @type {Record<string, Function>} */
for (const methodName of methodNames) {
methods[methodName] = iface[methodName];
iface[methodName] = (...args) =>
iface[methodName] = (/** @type {any[]} */ ...args) =>
promisifyMethodAnnotate(
iface,
methods[methodName],
@ -183,7 +193,10 @@ function emitNewRootSpanEvent(tracer, spanData) {
dbusSpanEmitter.emit('new-root-span', tracer, spanData);
}
/** @param {StartSpan} childSpanData */
/**
* @param {StartSpan} childSpanData
* @param {string} parentSpanId
*/
function emitNewChildSpanEvent(parentSpanId, childSpanData) {
dbusSpanEmitter.emit(`new-child-span-for/${parentSpanId}`, childSpanData);
}
@ -276,6 +289,9 @@ if (!process.env.XDG_CONFIG_HOME) {
process.env.XDG_CONFIG_HOME = process.env.HOME + '/.config';
}
/**
* @param {string} theme
* */
function getThemePathSync(theme) {
const path = `${themeDir}/${theme}.toml`;
const absolutePath = fs.realpathSync(path);
@ -346,6 +362,8 @@ function promisifyMethodAnnotate(obj, method, msg, ...args) {
/** write respective alacritty config if the colorscheme changes.
* Colorscheme changes are only tracked in-between calls to this function in-memory.
*
* @param {'prefer-dark' | 'prefer-light'} cs
*/
function writeAlacrittyColorConfigIfDifferent(cs) {
// only change the color scheme if it's different from the previous one
@ -391,6 +409,7 @@ async function exportColorSchemeDbusInterface() {
};
const ifaceImpl = {
/** @type {function('prefer-dark' | 'prefer-light'): void} */
SetColorScheme: function (cs) {
console.log(`SetColorScheme called with ${cs}`);
writeAlacrittyColorConfigIfDifferent(cs);
@ -482,6 +501,7 @@ async function exportOtelInterface() {
});
bus2.exportInterface(
{
/** @param {string} tracerName */
CreateTracer: function (tracerName) {
console.log(`Creating tracer with name ${tracerName}`);
const tracer = opentelemetry.trace.getTracer(tracerName, '0.0.1');
@ -515,14 +535,20 @@ async function getParentCallsite() {
return cs[2] ?? cs[1] ?? null;
}
/** @typedef {([true, StartSpan] | [false, EndSpan])} BatchSpan */
/**
* @typedef {{
* StartSpan: (spanData: StartSpan) => Promise<void>,
* EndSpan: (spanData: EndSpan) => Promise<void>,
* BatchSpans: (spans: BatchSpan[]) => Promise<void>
* }} TracerIface
*/
/** Calls the tracer dbus interface, sets up a tracer
*
* @param {string} tracerName The name of the tracer to set up
* @returns {Promise<{
* StartSpan: (spanData: StartSpan) => Promise<void>,
* EndSpan: (spanData: EndSpan) => Promise<void>,
* BatchSpans: (spans: ([true, StartSpan] | [false, EndSpan])[]) => Promise<void>
* }>}
* @returns {Promise<TracerIface>}
*/
async function setupTracer(tracerName) {
const parentCallsite = await getParentCallsite();
@ -541,7 +567,7 @@ async function setupTracer(tracerName) {
* @typedef {{
* StartSpan: (spanData: string) => Promise<void>,
* EndSpan: (spanData: string) => Promise<void>
* BatchSpans: ([bool, string]) => Promise<void>
* BatchSpans: (spans: [boolean, string][]) => Promise<void>
* }} Tracer
* @type {IfaceReturn<Tracer>}
* */
@ -551,12 +577,17 @@ async function setupTracer(tracerName) {
path,
);
/** @param {StartSpan} spanData */
function StartSpan(spanData) {
return tracerIface.StartSpan(JSON.stringify(spanData));
}
/**
* @param {any} spanData
*/
function EndSpan(spanData) {
return tracerIface.EndSpan(JSON.stringify(spanData));
}
/** @param {[boolean, unknown][]} spans */
function BatchSpans(spans) {
return tracerIface.BatchSpans(
spans.map(([isStartSpan, span]) => [isStartSpan, JSON.stringify(span)]),
@ -569,58 +600,145 @@ async function setupTracer(tracerName) {
};
}
/** @typedef {{}} Span */
/** @typedef {{name: string, attributes?: opentelemetry.Attributes, parentSpan?: Span}} SpanData */
class Tracer {
/** @param {string} tracerName */
static async setup(tracerName) {
const iface = await setupTracer(tracerName);
return new Tracer(tracerName, iface);
}
/**
* @param {string} tracerName
* @param {TracerIface} iface
*/
constructor(tracerName, iface) {
this.tracerName = tracerName;
const batch = new EventEmitter();
/**
* @type {BatchSpan[]}
*/
const batchQueue = [];
async function sendBatch() {
if (batchQueue.length > 0) {
await iface.BatchSpans(batchQueue);
batchQueue.length = 0;
}
}
/**
* @param {StartSpan} spanData
*/
function onNewSpan(spanData) {
batchQueue.push([true, spanData]);
if (batchQueue.length > 10) {
sendBatch();
}
}
/**
* @param {EndSpan} spanData
*/
function onEndSpan(spanData) {
batchQueue.push([false, spanData]);
if (batchQueue.length > 10) {
sendBatch();
}
}
batch.on('new-span', onNewSpan);
batch.on('end-span', onEndSpan);
let errorCounter = 0;
async function batchTimeout() {
const BATCH_TIMEOUT = 100;
try {
await setTimeout(BATCH_TIMEOUT);
await sendBatch();
} catch (e) {
errorCounter++;
throw e;
} finally {
if (errorCounter > 5) {
console.warn('Too many errors, stopping batchTimeout');
throw new Error('Too many errors, had to stop batchTimeout');
}
await setTimeout(BATCH_TIMEOUT).then(batchTimeout);
}
}
batchTimeout();
/** @param {StartSpan} spanData */
function startSpan(spanData) {
batch.emit('new-span', spanData);
}
/** @param {EndSpan} spanId */
function endSpan(spanId) {
batch.emit('end-span', { spanId });
}
this.batch = {
startSpan,
endSpan,
};
}
/**
* @template A
* @param {SpanData} spanData
* @param {function(Span): A} f
*/
async withSpan(spanData, f) {
const spanId = this.tracerName + '-' + pseudoRandomBytes(16).toString('hex');
const startTime = hrTime();
// @ts-ignore spanId is an internal impl detaul to our Span type
const parentId = spanData.parentSpan?.spanId;
try {
this.batch.startSpan({
spanId,
name: spanData.name,
attributes: spanData.attributes,
startTime,
parentId,
});
const span = { spanId };
return await f(span);
} finally {
this.batch.endSpan({ spanId });
}
}
}
async function main() {
await exportOtelInterface();
const tracer = await setupTracer('hello');
await tracer.StartSpan({
name: 'hello',
spanId: 'hello',
startTime: hrTime(),
attributes: {
foo: 'bar',
},
});
await tracer.StartSpan({
name: 'world',
spanId: 'world',
parentId: 'hello',
attributes: {
bar: 'baz',
},
});
await tracer.EndSpan({
spanId: 'world',
endTime: hrTime(),
});
await tracer.EndSpan({
spanId: 'hello',
endTime: hrTime(),
});
const t = performance.now();
await tracer.BatchSpans([
[
true,
{
name: 'batchy',
spanId: 'batchy',
startTime: t,
attributes: { foo: 'bar' },
const tracer = await Tracer.setup('hello');
await tracer.withSpan(
{
name: 'hello',
attributes: {
foo: 'bar',
},
],
[
true,
{
name: 'worldy',
spanId: 'worldy',
parentId: 'batchy',
startTime: t + 100,
attributes: { bar: 'baz' },
},
],
[false, { spanId: 'worldy', endTime: t + 500 }],
[false, { spanId: 'batchy', endTime: t + 1000 }],
]);
},
async span => {
await tracer.withSpan(
{
parentSpan: span,
name: 'world',
attributes: {
bar: 'baz',
},
},
async () => {
// Code inside the nested span
},
);
// Code after the nested span
},
);
await exportColorSchemeDbusInterface();