Note: This is an experimental package under active development. New releases may include breaking changes.
Note: Much of OpenTelemetry JS documentation is written assuming the compiled application is run as CommonJS. For more details on ECMAScript Modules vs CommonJS, refer to esm-support.
npm install --save @opentelemetry/instrumentationimport {
InstrumentationBase,
InstrumentationConfig,
InstrumentationNodeModuleDefinition,
InstrumentationNodeModuleFile,
} from '@opentelemetry/instrumentation';
import type * as module_name_to_be_patched from 'module_name_to_be_patched';
export class MyInstrumentation extends InstrumentationBase {
constructor(config: InstrumentationConfig = {}) {
super('MyInstrumentation', VERSION, config);
}
/**
* Init method will be called when the plugin is constructed.
* It returns an `InstrumentationNodeModuleDefinition` which describes
* the node module to be instrumented and patched.
* It may also return a list of `InstrumentationNodeModuleDefinition`s if
* the plugin should patch multiple modules or versions.
*/
protected init() {
const module = new InstrumentationNodeModuleDefinition(
'module_name_to_be_patched',
['1.*'],
this._onPatchMain,
this._onUnPatchMain,
);
// in case you need to patch additional files - this is optional
module.files.push(this._addPatchingMethod());
return module;
// you can also define more modules then just return an array of modules
// return [module1, module2, ....]
}
private _onPatchMain(moduleExports: typeof module_name_to_be_patched) {
this._wrap(
moduleExports,
'mainMethodName',
this._patchMainMethodName()
);
return moduleExports;
}
private _onUnPatchMain(moduleExports: typeof module_name_to_be_patched) {
this._unwrap(moduleExports, 'mainMethodName');
}
private _addPatchingMethod(): InstrumentationNodeModuleFile {
const file = new InstrumentationNodeModuleFile(
'module_name_to_be_patched/src/some_file.js',
this._onPatchMethodName,
this._onUnPatchMethodName,
);
return file;
}
private _onPatchMethodName(moduleExports: typeof module_name_to_be_patched) {
this._wrap(
moduleExports,
'methodName',
this._patchMethodName()
);
return moduleExports;
}
private _onUnPatchMethodName(moduleExports: typeof module_name_to_be_patched) {
this._unwrap(moduleExports, 'methodName');
}
private _patchMethodName(): (original) => any {
const plugin = this;
return function methodName(original) {
return function patchMethodName(this: any): PromiseOrValue<module_name_to_be_patched.methodName> {
console.log('methodName', arguments);
return original.apply(this, arguments);
};
};
}
private _patchMainMethodName(): (original) => any {
const plugin = this;
return function mainMethodName(original) {
return function patchMainMethodName(this: any): PromiseOrValue<module_name_to_be_patched.mainMethodName> {
console.log('mainMethodName', arguments);
return original.apply(this, arguments);
};
};
}
}
// Later, but before the module to instrument is required
const myInstrumentation = new MyInstrumentation();
myInstrumentation.setTracerProvider(provider); // this is optional, only if global TracerProvider shouldn't be used
myInstrumentation.setMeterProvider(meterProvider); // this is optional
myInstrumentation.enable();
// or use Auto Loaderimport {
InstrumentationBase,
InstrumentationConfig,
} from '@opentelemetry/instrumentation';
import { Instrumentation } from '@opentelemetry/instrumentation';
export class MyInstrumentation extends InstrumentationBase {
constructor(config: InstrumentationConfig = {}) {
super('MyInstrumentation', VERSION, config);
}
private _patchOpen() {
return (original: OpenFunction): OpenFunction => {
const plugin = this;
return function patchOpen(this: XMLHttpRequest, ...args): void {
console.log('open', arguments);
return original.apply(this, args);
};
};
}
public enable() {
this._wrap(XMLHttpRequest.prototype, 'open', this._patchOpen());
}
public disable() {
this._unwrap(XMLHttpRequest.prototype, 'open');
}
}
// Later
const myInstrumentation = new MyInstrumentation();
myInstrumentation.setTracerProvider(provider); // this is optional, only if global TracerProvider shouldn't be used
myInstrumentation.setMeterProvider(meterProvider); // this is optional, only if global MeterProvider shouldn't be used
myInstrumentation.enable();
// or use Auto Loaderconst { B3Propagator } = require('@opentelemetry/propagator-b3');
const { registerInstrumentations } = require('@opentelemetry/instrumentation');
const { HttpInstrumentation } = require('@opentelemetry/instrumentation-http');
const { NodeTracerProvider } = require('@opentelemetry/sdk-trace-node');
const tracerProvider = new NodeTracerProvider();
tracerProvider.register({
propagator: new B3Propagator(),
});
registerInstrumentations({
instrumentations: [
new HttpInstrumentation(),
],
//tracerProvider: tracerProvider, // optional, only if global TracerProvider shouldn't be used
//meterProvider: meterProvider, // optional, only if global MeterProvider shouldn't be used
});const { B3Propagator } = require('@opentelemetry/propagator-b3');
const { registerInstrumentations } = require('@opentelemetry/instrumentation');
const { XMLHttpRequestInstrumentation } = require('@opentelemetry/instrumentation-xml-http-request');
const { WebTracerProvider } = require('@opentelemetry/sdk-trace-web');
const tracerProvider = new WebTracerProvider();
tracerProvider.register({
propagator: new B3Propagator(),
});
registerInstrumentations({
instrumentations: [
new XMLHttpRequestInstrumentation({
ignoreUrls: [/localhost/],
propagateTraceHeaderCorsUrls: [
'http://localhost:8090',
],
}),
],
//tracerProvider: tracerProvider, // optional, only if global TracerProvider shouldn't be used
//meterProvider: meterProvider, // optional, only if global MeterProvider shouldn't be used
});The registerInstrumentations() API allows to specify which TracerProvider and/or MeterProvider to use by the given options object.
If nothing is specified the global registered provider is used. Usually this is what most users want therefore it's recommended to keep this default.
There might be use case where someone has the need for more providers within an application. Please note that special care must be takes in such setups
to avoid leaking information from one provider to the other because there are a lot places where e.g. the global ContextManager or Propagator is used.
Node.js uses a different module loader for ECMAScript Modules (ESM) vs. CommonJS (CJS).
A require() call will cause Node.js to use the CommonJS module loader.
An import ... statement or import() call will cause Node.js to use the ECMAScript module loader.
If your application is written in JavaScript as ESM, or it must compile to ESM from TypeScript, then a loader hook is required to properly patch instrumentation.
The custom hook for ESM instrumentation is --experimental-loader=@opentelemetry/instrumentation/hook.mjs.
This flag must be passed to the node binary, which is often done as a startup command and/or in the NODE_OPTIONS environment variable.
For more details on ECMAScript Modules vs CommonJS, refer to esm-support.
Instrumentations for external modules (e.g. express, mongodb,...) hooks the require call or import statement. Therefore following conditions need to be met that this mechanism can work:
- Instrumentations are registered before the module to instrument is
requireed (CJS only) - modules are not included in a bundle. Tools like
esbuild,webpack, ... usually have some mechanism to exclude specific modules from bundling
Apache 2.0 - See LICENSE for more information.
- For more information on OpenTelemetry, visit: https://opentelemetry.io/
- For help or feedback on this project, join us in GitHub Discussions