Execution Context

Access execution information and control test execution.

The execution context API provides information about the current test execution state.

Import

import exec from 'k6/execution';

Properties

exec.instance

Provides information about the local k6 instance.

currentTestRunDuration · number

Current test run duration in milliseconds

iterationsCompleted · number

Number of completed iterations

iterationsInterrupted · number

Number of interrupted iterations

vusActive · number

Number of currently active VUs

vusInitialized · number

Number of initialized VUs

import exec from 'k6/execution';

export default function () {
  console.log(`Test duration: ${exec.instance.currentTestRunDuration}ms`);
  console.log(`Active VUs: ${exec.instance.vusActive}`);
}

exec.scenario

Provides information about the current scenario.

name · string

Scenario name

executor · string

Executor type (e.g., “ramping-vus”, “constant-vus”)

startTime · number

Scenario start time (Unix timestamp in milliseconds)

progress · number

Scenario progress (0 to 1)

iterationInInstance · number

Current VU’s iteration number in this instance

iterationInTest · number

Current VU’s iteration number across all instances

import exec from 'k6/execution';

export default function () {
  console.log(`Scenario: ${exec.scenario.name}`);
  console.log(`Progress: ${exec.scenario.progress * 100}%`);
  console.log(`Iteration: ${exec.scenario.iterationInInstance}`);
}

exec.vu

Provides information about the current VU.

idInInstance · number

VU ID within the local instance (1-based)

idInTest · number

VU ID globally across all instances (1-based)

iterationInInstance · number

Current iteration number for this VU in the instance

iterationInScenario · number

Current iteration number for this VU in the scenario

tags · object

Dynamic object for getting/setting VU tags

metrics · object

Object containing tags and metadata

import exec from 'k6/execution';

export default function () {
  console.log(`VU ID: ${exec.vu.idInInstance}`);
  console.log(`Iteration: ${exec.vu.iterationInInstance}`);
  
  // Set custom tags
  exec.vu.tags['custom_tag'] = 'value';
}

exec.test

Provides test-level information and control.

options · object

Consolidated test options (read-only)

abort([message]) · function

Aborts the test execution immediately

fail([message]) · function

Marks the test as failed but continues execution

import exec from 'k6/execution';
import http from 'k6/http';

export default function () {
  const res = http.get('https://test.k6.io');
  
  // Abort test if critical error
  if (res.status === 500) {
    exec.test.abort('Server returned 500');
  }
  
  // Mark test as failed but continue
  if (res.timings.duration > 5000) {
    exec.test.fail('Response too slow');
  }
  
  // Access test options
  console.log(`Test duration: ${exec.test.options.duration}`);
}

Examples

VU-specific Behavior

import exec from 'k6/execution';
import http from 'k6/http';

export default function () {
  const vuId = exec.vu.idInInstance;
  
  // Use different endpoints based on VU ID
  const endpoint = vuId % 2 === 0 ? '/api/v1' : '/api/v2';
  http.get(`https://test.k6.io${endpoint}`);
}

Progress Monitoring

import exec from 'k6/execution';

export default function () {
  const progress = exec.scenario.progress;
  
  // Log progress every 10%
  if (progress > 0 && progress % 0.1 < 0.01) {
    console.log(`Test is ${Math.floor(progress * 100)}% complete`);
  }
}

Conditional Abort

import exec from 'k6/execution';
import http from 'k6/http';

let errorCount = 0;

export default function () {
  const res = http.get('https://test.k6.io');
  
  if (res.status !== 200) {
    errorCount++;
  }
  
  // Abort if too many errors
  if (errorCount > 100) {
    exec.test.abort('Too many errors detected');
  }
}

Dynamic Tagging

import exec from 'k6/execution';
import http from 'k6/http';

export default function () {
  // Add scenario-specific tags
  exec.vu.tags['scenario'] = exec.scenario.name;
  exec.vu.tags['vu_id'] = exec.vu.idInInstance.toString();
  
  http.get('https://test.k6.io');
}

Iteration-based Logic

import exec from 'k6/execution';
import http from 'k6/http';

export default function () {
  const iteration = exec.scenario.iterationInInstance;
  
  // Warmup for first 10 iterations
  if (iteration < 10) {
    console.log('Warmup iteration');
    return;
  }
  
  // Normal test execution
  http.get('https://test.k6.io');
}

Execution context properties cannot be accessed in the init context. They are only available in the VU context (default function).