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Documentation Grafana k6 JavaScript API k6/experimental fs open

open

The open function opens a file and returns a promise that resolves to a File instance. Unlike the traditional open function, which loads a file multiple times into memory, the filesystem module reduces memory usage by loading the file as little possible, and sharing the same memory space between all VUs. This approach reduces the risk of encountering out-of-memory errors, especially in load tests involving large files.

Parameters

Returns

A promise resolving to a File instance.

Example

JavaScript

Copy

JavaScript Copy

import { open } from 'k6/experimental/fs';

// k6 doesn't support async in the init context. We use a top-level async function for `await`.
//
// Each Virtual User gets its own `file` copy.
// So, operations like `seek` or `read` won't impact other VUs.
const file = await open('bonjour.txt');

export default async function () {
  // About information about the file
  const fileinfo = await file.stat();
  if (fileinfo.name != 'bonjour.txt') {
    throw new Error('Unexpected file name');
  }

  console.log(JSON.stringify(fileinfo));
}