v0.20.0

Lots of goodies in this release! 🎉

We are working towards a 1.0 release of k6, and as part of this release we've also published our roadmap for 2018 in the Github wiki, here it is. We welcome comments and discussion relating to the roadmap, both in the corresponding issues as well as in Slack.

Once again we saw contributions from several members of the community in this release, from 9 people outside of Load Impact, woop woop! A big thanks to the following people for contributing to this release: @antekresic, @cstyan, @cyberw, @danron, @dstpierre, @luizbafilho, @marklagendijk, @na-- and @pkruhlei.

Two of the above contributors have also become full time employees of Load Impact since the last release, to accelerate the development of k6. We welcome @luizbafilho and @na-- to the distributed k6 core team!

To see the current plan for the next release, check out this milestone.

New Features!

k6/http: Support for binary files and multipart requests (#370, #420 and #524)

The init context open() function now supports binary files:

import http from "k6/http";
import {md5} from "k6/crypto";

let binFile = open("./image.png", "b");

export default function() {
    console.log(md5(binFile, "hex"));
}

and the HTTP module has handily gained support for multipart requests:

import http from "k6/http";

let binFile = open("./image.png", "b");

export default function() {
    var data = {
        field: "this is a standard form field",
        file: http.file(binFile, "my image file.png")
    };
    var res = http.post("https://example.com/upload", data);
}

Thanks @dstpierre for their work on this!

Docs: Multipart requests

k6/http: Request information through response object (#447)

Request information is now exposed through the Response object:

import http from "k6/http";

export default function() {
    let res = http.get("https://example.com/")
    console.log(`Method: ${res.request.method}`);
    new Map(Object.entries(res.request.headers)).forEach((v, k) => console.log(`Header: ${k}=${v}`));
    console.log(`Body: ${res.request.method}`);
}

Thanks to @cstyan for their work on this!

Docs: Request information

Lifecycle: setup/teardown functions (#457)

Finally k6 has the same basic test lifecycle hooks as many "normal" testing tools, setup and teardown, and you have the full JS API of k6 available within these functions which means you can make HTTP calls etc. that you can’t do in the global/init scope.

To use the lifecycle hooks you simply define an exported setup() and/or teardown() function in your script:

export function setup() {
	return { “data”: “passed to main and teardown function” };
}

export function teardown(data)  {
	console.log(JSON.stringify(data));
}

export default function(data) {
if (data.v != 1) {
		throw new Error("incorrect data: " + JSON.stringify(data));
	}
}

Docs: Test life cycle

CLI: HTTP debug flag (#447)

If you specify --http-debug when running a test k6 will now continuously print request and response information.

Thanks to @marklagendijk for their work on this!

Docs: HTTP debugging

Options: DNS override (#494)

Overriding DNS resolution of hostnames can come in handy when testing a system that is run in multiple environments (dev, staging, prod etc.) with different IP addresses but responds to the same Host header.

import http from "k6/http";

export let options = {
    hosts: {
        "loadimpact.com": "1.2.3.4",
        "test.loadimpact.com": "5.6.7.8"
    }
};

export default function() {
    http.get("http://loadimpact.com/");
    http.get("http://test.loadimpact.com/");
}

Tip: you can use environment variables to switch the IP based on environment.

Thanks @luizbafilho for their work on this!

Docs: DNS Override option

CLI: Add -e flag environment variable flag (#495)

You can now specify any number of environment variables on the command line using the -e NAME=VALUE flag.

As a matter of security, when running k6 cloud ... or k6 archive ... the system's environment variables will not be included in the resulting archive, you'll now have to use the new --include-system-env-vars flag to get that behavior. When executing k6 run ... the system's environment will continue to be exposed to your script.

We encourage the use of -e NAME=VALUE to make environment variable use explicit and compatible across local and cloud execution.

Thanks @na-- for their work on this!

Docs: Environment variables

HAR converter: Add --no-batch flag (#497)

A --no-batch CLI flag has been added to k6 convert command to disable the creation of batch request statements in favor of individual http.get/del/options/patch/post/put statements.

Thanks @danron and @cyberw for their work on this!

HAR converter: Add --return-on-failed-check flag (#499)

A --return-on-failed-check CLI flag has been added to k6 convert command to optionally return/exit the current VU iteration if a response status code check fails (requires the existing --enable-status-code-checks to be specified as well).

Thanks @cyberw for their work on this!

HAR converter: Add --correlate flag (#500)

A first step towards doing correlations when converting HAR to JS has implemented. In this first iteration, if --correlate is specified the converter will try to detect issues with redirects.

Thanks @cyberw for their work on this!

Stats: Use linear interpolation when calculating percentiles (#498)

The percentile calculation has been changed to use linear interpolation of two bounding values if percentile doesn't precisely fall on a value/sample index.

Thresholds: Support for aborting test early as soon as threshold is hit (#508)

Up until now thresholds were evaluated continuously throughout the test but could never abort a running test.
This PR adds functionality to specify that a test run should abort the test as soon as a threshold evaluates to false, optionally with a delay in threshold evaluation to avoid aborting to early when the number of samples collected is low.

export let options = {
    thresholds: {
        "http_req_duration": ["avg<100", { threshold: "p(95)<200", abortOnFail: true, delayAbortEval: "30s" }]
    }
};

Thanks @antekresic for their work on this!

Docs: Thresholds with abort

Docker: Use full Alpine as base image for k6 (#514)

Thanks @pkruhlei for their contribution!

CLI: Option to whitelist what tags should be added to metric samples (#525)

Adds a CLI option --system-tags "url,method,status" to specify a whitelist of system tags that will be included in the metrics output.

The following tags can be specified:

• url (http, websocket)
• method (http)
• status (http, websocket)
• proto (http)
• subproto (websocket)
• error (http)
• name (http)
• group (http)
• check (http)
• tls_version (http)
• ocsp_status (http)
• iter (vu)
• vu (vu)

All but the last 3 (ocsp_status, iter, vu) are included by default. Some collectors (e.g. cloud) could require that certain tags are included.

Docs: System tags

k6/http: Support for HTTP Digest Authentication (#533)

import http from "k6/http";
import { check } from "k6";

export default function() {
    // Passing username and password as part of URL plus the auth option will authenticate using HTTP Digest authentication
    let res = http.get("http://user:passwd@httpbin.org/digest-auth/auth/user/passwd", {auth: "digest"});

    // Verify response
    check(res, {
        "status is 200": (r) => r.status === 200,
        "is authenticated": (r) => r.json().authenticated === true,
        "is correct user": (r) => r.json().user === "user"
    });
}

Docs: HTTP Params

Bugs fixed!

• HAR converter: Fixed issue with construction of body parameter when PostData.Params values are present. (#489)

• Stats: Fixed output of rate metrics to truncate rather than round when converting to string representation from float for summary output.

• Stats: Fixes issue where calls to TrendSink.P() and TrendSink.Format() could return wrong results if TrendSink.Calc() hadn't been previously called. (#498)

• Cloud/Insights: Fixed issue causing default test name to be empty when parsing script from STDIN (#510)

• Cloud/Insights: Fixed handling of unexpected responses from server. (#522)

• Stats: Fixed issue with calculation of data_received and data_sent metrics. (#523)

• WebSockets: Fixed issue that different TLS settings like InsecureSkipTLSVerify were ignored for websockets (#531)

Breaking changes

• The SummaryTrendStats configuration option has been renamed to summaryTrendStats, to match all of the other JS option names.