# OpenTelemetry Memcached Instrumentation for Node.js

[![NPM Published Version][npm-img]][npm-url]
[![Apache License][license-image]][license-image]

This module provides automatic instrumentation for the [`memcached@>=2.2.0`][repo-url] module.

If total installation size is not constrained, it is recommended to use the [`@opentelemetry/auto-instrumentations-node`](https://www.npmjs.com/package/@opentelemetry/auto-instrumentations-node) bundle with [@opentelemetry/sdk-node](`https://www.npmjs.com/package/@opentelemetry/sdk-node`) for the most seamless instrumentation experience.

Compatible with OpenTelemetry JS API and SDK `1.0+`.

## Installation

```bash
npm install --save @opentelemetry/instrumentation-memcached
```

### Supported Versions

- [`memcached`](https://www.npmjs.com/package/memcached) versions `>=2.2.0 <3`

## Usage

OpenTelemetry Memcached Instrumentation allows the user to automatically collect trace data and export them to the backend of choice, to give observability to distributed systems when working with [memcached][pkg-url].

To enable a specific instrumentation, pass it to `registerInstrumentations()`.
This is commonly done via `NodeSDK` for fully setting up all OpenTelemetry SDK components:

```js
const { NodeSDK } = require('@opentelemetry/sdk-node');
const { MemcachedInstrumentation } = require('@opentelemetry/instrumentation-memcached');

const sdk = new NodeSDK({
  instrumentations: [
    new MemcachedInstrumentation({
      // See below for configuration options.
    }),
  ],
});
sdk.start();
process.once('beforeExit', async () => { await sdk.shutdown(); });
```

### Configuration Options

| Option                      | Type      | Example | Description                                                                                                                  |
| --------------------------- | --------- | ------- | ---------------------------------------------------------------------------------------------------------------------------- |
| `enhancedDatabaseReporting` | `boolean` | `false` | Include full command statement in the span - **leaks potentially sensitive information to your spans**. Defaults to `false`. |

## Semantic Conventions

The `@opentelemetry/instrumentation-memcached` versions 0.63.0 and later emit the stable semantic conventions.

Attributes collected:

| Attribute           | Description                                                                             |
| ------------------- | --------------------------------------------------------------------------------------- |
| `db.system.name`    | 'memcached'                                                                             |
| `db.operation.name` | The name of the operation being executed.                                               |
| `db.query.text`     | The database statement being executed (only if `enhancedDatabaseReporting` is enabled). |
| `server.address`    | Remote hostname or similar.                                                             |
| `server.port`       | Remote port number.                                                                     |

## Useful links

- For more information on OpenTelemetry, visit: <https://opentelemetry.io/>
- For more about OpenTelemetry JavaScript: <https://github.com/open-telemetry/opentelemetry-js>
- For help or feedback on this project, join us in [GitHub Discussions][discussions-url]

## License

Apache 2.0 - See [LICENSE][license-url] for more information.

[discussions-url]: https://github.com/open-telemetry/opentelemetry-js/discussions
[license-url]: https://github.com/open-telemetry/opentelemetry-js-contrib/blob/main/LICENSE
[license-image]: https://img.shields.io/badge/license-Apache_2.0-green.svg?style=flat
[npm-url]: https://www.npmjs.com/package/@opentelemetry/instrumentation-memcached
[npm-img]: https://badge.fury.io/js/%40opentelemetry%2Finstrumentation-memcached.svg
[repo-url]: https://github.com/3rd-Eden/memcached
[pkg-url]: https://www.npmjs.com/package/memcached