Menu

This is documentation for the next version of K6. For the latest stable release, go to the latest version.

Documentationbreadcrumb arrow Grafana k6breadcrumb arrow Using k6breadcrumb arrow Execution context variables
Open source

Execution context variables

In some cases, it’s really useful to have information about the script’s current test-execution state. For example, you might want to

  • Have different VUs run different test logic
  • Use different data for each VU and iteration
  • Figure out the stage that a test is in

To solve these issues, you can use execution context variables.

k6/execution

The k6/execution module exposes details about the current execution state, such as the name of the currently executed scenario, how many VUs are currently active, and more. The module provides test-execution information via three properties:

PropertyMeta-information and execution details about
instanceThe current running k6 instance
scenarioThe current running scenario
vuThe current VU and iteration

Example: log all context variables

If you want to experiment with what each context variable looks like as a test runs, you can copy this template literal into one of your test scripts.

Note that this omits the abort variable, since that function would abort the test.

JavaScript
import exec from 'k6/execution';

export default function () {
  console.log(`Execution context

Instance info
-------------
Vus active: ${exec.instance.vusActive}
Iterations completed: ${exec.instance.iterationsCompleted}
Iterations interrupted:  ${exec.instance.iterationsInterrupted}
Iterations completed:  ${exec.instance.iterationsCompleted}
Iterations active:  ${exec.instance.vusActive}
Initialized vus:  ${exec.instance.vusInitialized}
Time passed from start of run(ms):  ${exec.instance.currentTestRunDuration}

Scenario info
-------------
Name of the running scenario: ${exec.scenario.name}
Executor type: ${exec.scenario.executor}
Scenario start timestamp: ${exec.scenario.startTime}
Percenatage complete: ${exec.scenario.progress}
Iteration in instance: ${exec.scenario.iterationInInstance}
Iteration in test: ${exec.scenario.iterationInTest}

Test info
---------
All test options: ${exec.test.options}

VU info
-------
Iteration id: ${exec.vu.iterationInInstance}
Iteration in scenario: ${exec.vu.iterationInScenario}
VU ID in instance: ${exec.vu.idInInstance}
VU ID in test: ${exec.vu.idInTest}
VU tags: ${exec.vu.tags}`);
}

For detailed reference, refer to the k6/execution module.

Additional examples

Grafana Cloud k6 context variables

Grafana Cloud k6 injects additional context variables into a running cloud test. These variables provide information about the server (K6_CLOUDRUN_INSTANCE_ID), load zone (K6_CLOUDRUN_LOAD_ZONE),instance ID (K6_CLOUDRUN_INSTANCE_ID), and cloud distribution (K6_CLOUDRUN_DISTRIBUTION).

Refer to Cloud execution context variables for more details.