open( filePath, [mode] )
Opens a file, reading all its contents into memory for use in the script.
Caution
open()
can only be called from the init context. This restriction is necessary to determine the local files needed to bundle when distributing the test across multiple nodes.
Note
open()
often consumes a large amount of memory because every VU keeps a separate copy of the file in memory.To reduce the memory consumption, you can:
- Use
open()
within a SharedArray, which shares the allocated file memory between VUs.- Use open() from the
k6/experimental/fs
module. It provides a memory-efficient way to handle file interactions in your test script and can read files in small chunks.
Returns
Examples
[
{
"username": "user1",
"password": "password1"
},
{
"username": "user2",
"password": "password2"
},
{
"username": "user3",
"password": "password3"
}
]
import { SharedArray } from 'k6/data';
import { sleep } from 'k6';
const data = new SharedArray('users', function () {
// here you can open files, and then do additional processing or generate the array with data dynamically
const f = JSON.parse(open('./users.json'));
return f; // f must be an array[]
});
export default () => {
const randomUser = data[Math.floor(Math.random() * data.length)];
console.log(`${randomUser.username}, ${randomUser.password}`);
sleep(3);
};
import { sleep } from 'k6';
const users = JSON.parse(open('./users.json')); // consider using SharedArray for large files
export default function () {
const user = users[__VU - 1];
console.log(`${user.username}, ${user.password}`);
sleep(3);
}
import http from 'k6/http';
import { sleep } from 'k6';
const binFile = open('/path/to/file.bin', 'b');
export default function () {
const data = {
field: 'this is a standard form field',
file: http.file(binFile, 'test.bin'),
};
const res = http.post('https://example.com/upload', data);
sleep(3);
}