93 lines
3.6 KiB
Markdown
93 lines
3.6 KiB
Markdown
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# OpenTelemetry Metrics SDK
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[![NPM Published Version][npm-img]][npm-url]
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[![Apache License][license-image]][license-image]
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This module contains the Metrics SDK of [opentelemetry-js](https://github.com/open-telemetry/opentelemetry-js).
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Used standalone, this module provides methods for manual instrumentation of code, offering full control over recording metrics for client-side JavaScript (browser) and Node.js.
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It does **not** provide automated instrumentation of known libraries or host environment metrics out-of-the-box.
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## Installation
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```bash
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npm install --save @opentelemetry/api
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npm install --save @opentelemetry/sdk-metrics
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```
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## Usage
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The basic setup of the SDK can be seen as followings:
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```js
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const opentelemetry = require('@opentelemetry/api');
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const { MeterProvider } = require('@opentelemetry/sdk-metrics');
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// To create an instrument, you first need to initialize the Meter provider.
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// NOTE: The default OpenTelemetry meter provider does not record any metric instruments.
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// Registering a working meter provider allows the API methods to record instruments.
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opentelemetry.metrics.setGlobalMeterProvider(new MeterProvider());
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// To record a metric event, we used the global singleton meter to create an instrument.
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const counter = opentelemetry.metrics.getMeter('default').createCounter('foo');
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// record a metric event.
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counter.add(1, { attributeKey: 'attribute-value' });
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```
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In conditions, we may need to setup an async instrument to observe costly events:
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```js
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// Creating an async instrument, similar to synchronous instruments
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const observableCounter = opentelemetry.metrics.getMeter('default')
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.createObservableCounter('observable-counter');
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// Register a single-instrument callback to the async instrument.
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observableCounter.addCallback(async (observableResult) => {
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// ... do async stuff
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observableResult.observe(1, { attributeKey: 'attribute-value' });
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});
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// Register a multi-instrument callback and associate it with a set of async instruments.
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opentelemetry.metrics.getMeter('default')
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.addBatchObservableCallback(batchObservableCallback, [ observableCounter ]);
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async function batchObservableCallback(batchObservableResult) {
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// ... do async stuff
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batchObservableResult.observe(observableCounter, 1, { attributeKey: 'attribute-value' });
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}
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```
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Views can be registered when instantiating a `MeterProvider`:
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```js
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const meterProvider = new MeterProvider({
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views: [
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// override the bucket boundaries on `my.histogram` to [0, 50, 100]
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new View({ aggregation: new ExplicitBucketHistogramAggregation([0, 50, 100]), instrumentName: 'my.histogram'}),
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// rename 'my.counter' to 'my.renamed.counter'
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new View({ name: 'my.renamed.counter', instrumentName: 'my.counter'})
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]
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})
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```
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## Example
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See [examples/prometheus](https://github.com/open-telemetry/opentelemetry-js/tree/main/experimental/examples/prometheus) for an end-to-end example, including exporting metrics.
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## Useful links
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- For more information on OpenTelemetry, visit: <https://opentelemetry.io/>
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- For more about OpenTelemetry JavaScript: <https://github.com/open-telemetry/opentelemetry-js>
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- For help or feedback on this project, join us in [GitHub Discussions][discussions-url]
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## License
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Apache 2.0 - See [LICENSE][license-url] for more information.
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[discussions-url]: https://github.com/open-telemetry/opentelemetry-js/discussions
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[license-url]: https://github.com/open-telemetry/opentelemetry-js/blob/main/LICENSE
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[license-image]: https://img.shields.io/badge/license-Apache_2.0-green.svg?style=flat
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[npm-url]: https://www.npmjs.com/package/@opentelemetry/sdk-metrics
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[npm-img]: https://badge.fury.io/js/%40opentelemetry%2Fsdk%2Dmetrics.svg
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