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Rate

Rate is an object for representing a custom metric keeping track of the percentage of added values that are non-zero. It is one of the four custom metrics.

ParameterTypeDescription
namestringThe name of the custom metric.
MethodDescription
Rate.add(value, [tags])Add a value to the rate metric.

Rate usage in Thresholds

When Rate is used in a threshold expression, the variable must be called rate (lower case). For example:

  • rate < 0.1 // less than 10%
  • rate >= 0.9 // more or equal to 90%

The value of the rate variable ranges between 0.00 and 1.00.

Examples

JavaScript 
import { Rate } from 'k6/metrics';

const myRate = new Rate('my_rate');

export default function () {
  myRate.add(true);
  myRate.add(false);
  myRate.add(1);
  myRate.add(0, { tag1: 'value', tag2: 'value2' });
}
JavaScript 
import { Rate } from 'k6/metrics';
import { sleep } from 'k6';
import http from 'k6/http';

const errorRate = new Rate('errorRate');

export const options = {
  vus: 1,
  duration: '5m',
  thresholds: {
    errorRate: [
      // more than 10% of errors will abort the test
      { threshold: 'rate < 0.1', abortOnFail: true, delayAbortEval: '1m' },
    ],
  },
};

export default function () {
  const resp = http.get('https://test-api.k6.io/public/crocodiles/1/');

  errorRate.add(resp.status >= 400);

  sleep(1);
}