From a91a30a815790465a19ad222c4ec22c92191c4c5 Mon Sep 17 00:00:00 2001
From: Andre Medeiros <me@andremedeiros.info>
Date: Wed, 15 Apr 2020 20:58:27 -0400
Subject: [PATCH 01/16] load plugins specified by the command line parameter

---
 cmd/common.go    |  8 ++++++++
 cmd/options.go   |  3 +++
 cmd/run.go       | 21 +++++++++++++++++----
 lib/options.go   |  3 +++
 lib/plugin.go    | 34 ++++++++++++++++++++++++++++++++++
 plugin/plugin.go | 40 ++++++++++++++++++++++++++++++++++++++++
 6 files changed, 105 insertions(+), 4 deletions(-)
 create mode 100644 lib/plugin.go
 create mode 100644 plugin/plugin.go

diff --git a/cmd/common.go b/cmd/common.go
index df2745f3b13..79468de265f 100644
--- a/cmd/common.go
+++ b/cmd/common.go
@@ -104,6 +104,14 @@ func getNullString(flags *pflag.FlagSet, key string) null.String {
 	return null.NewString(v, flags.Changed(key))
 }
 
+func getStringSlice(flags *pflag.FlagSet, key string) []string {
+	v, err := flags.GetStringSlice(key)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
 func exactArgsWithMsg(n int, msg string) cobra.PositionalArgs {
 	return func(cmd *cobra.Command, args []string) error {
 		if len(args) != n {
diff --git a/cmd/options.go b/cmd/options.go
index decdfe453d2..b1d11a5e841 100644
--- a/cmd/options.go
+++ b/cmd/options.go
@@ -82,6 +82,7 @@ func optionFlagSet() *pflag.FlagSet {
 	flags.StringSlice("tag", nil, "add a `tag` to be applied to all samples, as `[name]=[value]`")
 	flags.String("console-output", "", "redirects the console logging to the provided output file")
 	flags.Bool("discard-response-bodies", false, "Read but don't process or save HTTP response bodies")
+	flags.StringSlice("plugin", []string{}, "load a plugin at `path`")
 	return flags
 }
 
@@ -110,6 +111,8 @@ func getOptions(flags *pflag.FlagSet) (lib.Options, error) {
 		TeardownTimeout: types.NullDuration{Duration: types.Duration(10 * time.Second), Valid: false},
 
 		MetricSamplesBufferSize: null.NewInt(1000, false),
+
+		Plugins: getStringSlice(flags, "plugin"),
 	}
 
 	// Using Changed() because GetStringSlice() doesn't differentiate between empty and no value
diff --git a/cmd/run.go b/cmd/run.go
index 27c775e4766..e748ecbfac6 100644
--- a/cmd/run.go
+++ b/cmd/run.go
@@ -49,6 +49,7 @@ import (
 	"github.com/loadimpact/k6/lib/consts"
 	"github.com/loadimpact/k6/lib/types"
 	"github.com/loadimpact/k6/loader"
+	"github.com/loadimpact/k6/plugin"
 	"github.com/loadimpact/k6/ui"
 )
 
@@ -107,6 +108,22 @@ a commandline interface for interacting with it.`,
 			Left:  func() string { return "    init" },
 		}
 
+		// Load plugins
+		cliConf, err := getConfig(cmd.Flags())
+		if err != nil {
+			return err
+		}
+
+		plugins := []plugin.JavaScriptPlugin{}
+		for _, pluginPath := range cliConf.Plugins {
+			jsPlugin, err := lib.LoadPlugin(pluginPath)
+			if err != nil {
+				return err
+			}
+
+			plugins = append(plugins, jsPlugin)
+		}
+
 		// Create the Runner.
 		fprintf(stdout, "%s runner\r", initBar.String())
 		pwd, err := os.Getwd()
@@ -132,10 +149,6 @@ a commandline interface for interacting with it.`,
 
 		fprintf(stdout, "%s options\r", initBar.String())
 
-		cliConf, err := getConfig(cmd.Flags())
-		if err != nil {
-			return err
-		}
 		conf, err := getConsolidatedConfig(afero.NewOsFs(), cliConf, r)
 		if err != nil {
 			return err
diff --git a/lib/options.go b/lib/options.go
index f94341a3ff3..bbcff366216 100644
--- a/lib/options.go
+++ b/lib/options.go
@@ -285,6 +285,9 @@ type Options struct {
 
 	// Redirect console logging to a file
 	ConsoleOutput null.String `json:"-" envconfig:"K6_CONSOLE_OUTPUT"`
+
+	// Plugins to load
+	Plugins []string `json:"plugins" envconfig:"K6_PLUGINS"`
 }
 
 // Returns the result of overwriting any fields with any that are set on the argument.
diff --git a/lib/plugin.go b/lib/plugin.go
new file mode 100644
index 00000000000..f5b94e61f6c
--- /dev/null
+++ b/lib/plugin.go
@@ -0,0 +1,34 @@
+package lib
+
+import (
+	"fmt"
+	goplugin "plugin"
+
+	"github.com/loadimpact/k6/plugin"
+)
+
+func LoadJavaScriptPlugin(path string) (plugin.JavaScriptPlugin, error) {
+	p, err := loadPlugin(path)
+	if err != nil {
+		return nil, err
+	}
+
+	jsSym, err := p.Lookup("JavaScriptPlugin")
+	if err != nil {
+		return nil, err
+	}
+
+	var jsPlugin plugin.JavaScriptPlugin
+	jsPlugin, ok := jsSym.(plugin.JavaScriptPlugin)
+	if !ok {
+		return nil, fmt.Errorf("could not cast plugin to the right type")
+	}
+
+	return jsPlugin, nil
+}
+
+func loadPlugin(path string) (*goplugin.Plugin, error) {
+	// TODO: check for things like the file existing and return nicer errors
+	p, err := goplugin.Open(path)
+	return p, err
+}
diff --git a/plugin/plugin.go b/plugin/plugin.go
new file mode 100644
index 00000000000..35085e1aeae
--- /dev/null
+++ b/plugin/plugin.go
@@ -0,0 +1,40 @@
+/*
+ *
+ * k6 - a next-generation load testing tool
+ * Copyright (C) 2016 Load Impact
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+package plugin
+
+// A Plugin ...
+type Plugin interface {
+	// Returns a user-friendly name for the plugin.
+	Name() string
+
+	// Gets the plugin in a state where it can be utilized in a load balancing test.
+	Setup() error
+
+	// Cleans up any state / files that need cleaning right before k6 shuts down.
+	Teardown() error
+}
+
+type JavaScriptPlugin interface {
+	Plugin
+
+	// Returns a list of modules that this plugin exposes.
+	GetModules() map[string]interface{}
+}

From f6d5963d2ada9432377b6c1f0e641ee4a5b9b202 Mon Sep 17 00:00:00 2001
From: Andre Medeiros <me@andremedeiros.info>
Date: Wed, 15 Apr 2020 21:01:18 -0400
Subject: [PATCH 02/16] fix plugin load invocation

---
 cmd/run.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cmd/run.go b/cmd/run.go
index e748ecbfac6..ec3145b3173 100644
--- a/cmd/run.go
+++ b/cmd/run.go
@@ -116,7 +116,7 @@ a commandline interface for interacting with it.`,
 
 		plugins := []plugin.JavaScriptPlugin{}
 		for _, pluginPath := range cliConf.Plugins {
-			jsPlugin, err := lib.LoadPlugin(pluginPath)
+			jsPlugin, err := lib.LoadJavaScriptPlugin(pluginPath)
 			if err != nil {
 				return err
 			}

From f1c38d9df7c1aee9c7c29a8cef6d4664bdb6564c Mon Sep 17 00:00:00 2001
From: Andre Medeiros <me@andremedeiros.info>
Date: Wed, 15 Apr 2020 21:25:57 -0400
Subject: [PATCH 03/16] add plugin to modules; look plugins up on require;
 teardown plugins on run end

---
 cmd/run.go          | 19 +++++++++++++++++++
 js/initcontext.go   | 16 +++++++++++++++-
 js/modules/index.go |  3 +++
 3 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/cmd/run.go b/cmd/run.go
index ec3145b3173..ba905d7a608 100644
--- a/cmd/run.go
+++ b/cmd/run.go
@@ -45,6 +45,7 @@ import (
 	"github.com/loadimpact/k6/core"
 	"github.com/loadimpact/k6/core/local"
 	"github.com/loadimpact/k6/js"
+	"github.com/loadimpact/k6/js/modules"
 	"github.com/loadimpact/k6/lib"
 	"github.com/loadimpact/k6/lib/consts"
 	"github.com/loadimpact/k6/lib/types"
@@ -121,6 +122,18 @@ a commandline interface for interacting with it.`,
 				return err
 			}
 
+			// Run plugin setup and add it to the module tree
+			if err = jsPlugin.Setup(); err != nil {
+				return err
+			}
+
+			// TODO: does this belong here, or is it the module package's responsibility?
+			mods := jsPlugin.GetModules()
+			for path, api := range mods {
+				// TODO: check if module already exists and if we're not overloading it
+				modules.PluginIndex[path] = api
+			}
+
 			plugins = append(plugins, jsPlugin)
 		}
 
@@ -486,6 +499,12 @@ a commandline interface for interacting with it.`,
 			}
 		}
 
+		// Teardown plugins
+		for _, jsPlugin := range plugins {
+			// TODO: does it really matter if teardown errors?
+			jsPlugin.Teardown()
+		}
+
 		if conf.Linger.Bool {
 			logrus.Info("Linger set; waiting for Ctrl+C...")
 			<-sigC
diff --git a/js/initcontext.go b/js/initcontext.go
index f78620e099c..5f558027efa 100644
--- a/js/initcontext.go
+++ b/js/initcontext.go
@@ -113,8 +113,14 @@ func (i *InitContext) Require(arg string) goja.Value {
 		}
 		return v
 	default:
+		// Try in the plugin store
+		v, err := i.requirePluginModule(arg)
+		if err == nil {
+			return v
+		}
+
 		// Fall back to loading from the filesystem.
-		v, err := i.requireFile(arg)
+		v, err = i.requireFile(arg)
 		if err != nil {
 			common.Throw(i.runtime, err)
 		}
@@ -122,6 +128,14 @@ func (i *InitContext) Require(arg string) goja.Value {
 	}
 }
 
+func (i *InitContext) requirePluginModule(name string) (goja.Value, error) {
+	mod, ok := modules.PluginIndex[name]
+	if !ok {
+		return nil, errors.Errorf("unknown plugin module: %s", name)
+	}
+	return i.runtime.ToValue(common.Bind(i.runtime, mod, i.ctxPtr)), nil
+}
+
 func (i *InitContext) requireModule(name string) (goja.Value, error) {
 	mod, ok := modules.Index[name]
 	if !ok {
diff --git a/js/modules/index.go b/js/modules/index.go
index 7e6d15d2cd9..4529695aa45 100644
--- a/js/modules/index.go
+++ b/js/modules/index.go
@@ -42,3 +42,6 @@ var Index = map[string]interface{}{
 	"k6/html":        html.New(),
 	"k6/ws":          ws.New(),
 }
+
+// Index of plugin module implementations.
+var PluginIndex = map[string]interface{}{}

From fb2703d2cf818441468cebf2848901356e50082a Mon Sep 17 00:00:00 2001
From: Andre Medeiros <me@andremedeiros.info>
Date: Thu, 16 Apr 2020 20:45:08 -0400
Subject: [PATCH 04/16] wrap up plugin support; add tests

---
 .circleci/config.yml   |  7 +++++++
 Makefile               |  6 +++++-
 cmd/run.go             | 14 +++++---------
 js/initcontext.go      | 11 ++++++-----
 js/initcontext_test.go | 40 ++++++++++++++++++++++++++++++++++++++++
 js/modules/index.go    | 13 ++++++++++++-
 lib/options_test.go    |  5 +++++
 lib/plugin.go          |  6 +++++-
 plugin/plugin.go       |  3 ++-
 9 files changed, 87 insertions(+), 18 deletions(-)

diff --git a/.circleci/config.yml b/.circleci/config.yml
index f13908db9bd..642ebe4fc4c 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -64,6 +64,13 @@ jobs:
     working_directory: /home/circleci/.go_workspace/src/github.com/loadimpact/k6
     steps:
       - checkout
+      - run:
+          name: Build plugin artifact for tests
+          command: |
+            go version
+            pushd /tmp
+            go build -buildmode=plugin -o /tmp/leftpad.so github.com/andremedeiros/leftpad
+            popd
       - run:
           name: Run tests and code coverage
           command: |
diff --git a/Makefile b/Makefile
index c10bd275222..9d145d6eedb 100644
--- a/Makefile
+++ b/Makefile
@@ -10,8 +10,12 @@ build:
 format:
 	find . -name '*.go' -exec gofmt -s -w {} +
 
+.PHONY: plugin
+plugin:
+	pushd /tmp; go build -buildmode=plugin -o /tmp/leftpad.so github.com/andremedeiros/leftpad; popd
+
 .PHONY: check
-check:
+check: plugin
 	golangci-lint run --out-format=tab --new-from-rev master ./...
 	go test -race -timeout 210s ./...
 
diff --git a/cmd/run.go b/cmd/run.go
index ba905d7a608..29c6a1fb1d9 100644
--- a/cmd/run.go
+++ b/cmd/run.go
@@ -116,6 +116,7 @@ a commandline interface for interacting with it.`,
 		}
 
 		plugins := []plugin.JavaScriptPlugin{}
+		pluginNames := []string{}
 		for _, pluginPath := range cliConf.Plugins {
 			jsPlugin, err := lib.LoadJavaScriptPlugin(pluginPath)
 			if err != nil {
@@ -127,14 +128,9 @@ a commandline interface for interacting with it.`,
 				return err
 			}
 
-			// TODO: does this belong here, or is it the module package's responsibility?
-			mods := jsPlugin.GetModules()
-			for path, api := range mods {
-				// TODO: check if module already exists and if we're not overloading it
-				modules.PluginIndex[path] = api
-			}
-
+			modules.RegisterPluginModules(jsPlugin.GetModules())
 			plugins = append(plugins, jsPlugin)
+			pluginNames = append(pluginNames, jsPlugin.Name())
 		}
 
 		// Create the Runner.
@@ -275,6 +271,7 @@ a commandline interface for interacting with it.`,
 			}
 
 			fprintf(stdout, "  execution: %s\n", ui.ValueColor.Sprint("local"))
+			fprintf(stdout, "    plugins: %s\n", ui.ValueColor.Sprint(strings.Join(pluginNames, ", ")))
 			fprintf(stdout, "     output: %s%s\n", ui.ValueColor.Sprint(out), ui.ExtraColor.Sprint(link))
 			fprintf(stdout, "     script: %s\n", ui.ValueColor.Sprint(filename))
 			fprintf(stdout, "\n")
@@ -501,8 +498,7 @@ a commandline interface for interacting with it.`,
 
 		// Teardown plugins
 		for _, jsPlugin := range plugins {
-			// TODO: does it really matter if teardown errors?
-			jsPlugin.Teardown()
+			_ = jsPlugin.Teardown()
 		}
 
 		if conf.Linger.Bool {
diff --git a/js/initcontext.go b/js/initcontext.go
index 5f558027efa..e81fb75f02e 100644
--- a/js/initcontext.go
+++ b/js/initcontext.go
@@ -112,15 +112,16 @@ func (i *InitContext) Require(arg string) goja.Value {
 			common.Throw(i.runtime, err)
 		}
 		return v
-	default:
+	case strings.HasPrefix(arg, "k6-plugin/"):
 		// Try in the plugin store
 		v, err := i.requirePluginModule(arg)
-		if err == nil {
-			return v
+		if err != nil {
+			common.Throw(i.runtime, err)
 		}
-
+		return v
+	default:
 		// Fall back to loading from the filesystem.
-		v, err = i.requireFile(arg)
+		v, err := i.requireFile(arg)
 		if err != nil {
 			common.Throw(i.runtime, err)
 		}
diff --git a/js/initcontext_test.go b/js/initcontext_test.go
index a2b805c2454..8a6cd04e0d5 100644
--- a/js/initcontext_test.go
+++ b/js/initcontext_test.go
@@ -39,6 +39,7 @@ import (
 	"github.com/stretchr/testify/require"
 
 	"github.com/loadimpact/k6/js/common"
+	"github.com/loadimpact/k6/js/modules"
 	"github.com/loadimpact/k6/lib"
 	"github.com/loadimpact/k6/lib/netext"
 	"github.com/loadimpact/k6/stats"
@@ -233,6 +234,45 @@ func TestInitContextRequire(t *testing.T) {
 			assert.NoError(t, err)
 		})
 	})
+
+	t.Run("Plugins", func(t *testing.T) {
+		t.Run("leftpad", func(t *testing.T) {
+			plugin, err := lib.LoadJavaScriptPlugin("/tmp/leftpad.so")
+			assert.NoError(t, err)
+			assert.Equal(t, "Leftpad", plugin.Name())
+
+			modules.RegisterPluginModules(plugin.GetModules())
+
+			b, err := getSimpleBundle("/script.js", `
+				import { leftpad } from "k6-plugin/leftpad";
+				export default function() {
+				  return leftpad('test', 10, '=');
+				}
+			`)
+			if !assert.NoError(t, err, "bundle error") {
+				return
+			}
+
+			bi, err := b.Instantiate()
+			if !assert.NoError(t, err, "instance error") {
+				return
+			}
+
+			val, err := bi.Default(goja.Undefined())
+			if !assert.NoError(t, err) {
+				return
+			}
+			assert.Equal(t, "======test", val.Export())
+		})
+		t.Run("Nonexistent", func(t *testing.T) {
+			_, err := getSimpleBundle("/script.js", `
+				import { leftpad } from "k6-plugin/nonexistent";
+				export default function() {}
+			`)
+			require.Error(t, err)
+			assert.Contains(t, err.Error(), "unknown plugin module: k6-plugin/nonexistent")
+		})
+	})
 }
 
 func createAndReadFile(t *testing.T, file string, content []byte, expectedLength int, binary bool) (*BundleInstance, error) {
diff --git a/js/modules/index.go b/js/modules/index.go
index 4529695aa45..1ddeb008005 100644
--- a/js/modules/index.go
+++ b/js/modules/index.go
@@ -21,6 +21,8 @@
 package modules
 
 import (
+	"fmt"
+
 	"github.com/loadimpact/k6/js/modules/k6"
 	"github.com/loadimpact/k6/js/modules/k6/crypto"
 	"github.com/loadimpact/k6/js/modules/k6/crypto/x509"
@@ -43,5 +45,14 @@ var Index = map[string]interface{}{
 	"k6/ws":          ws.New(),
 }
 
-// Index of plugin module implementations.
+// PluginIndex holds a map of plugin modules to their respective implementations.
 var PluginIndex = map[string]interface{}{}
+
+// RegisterPluginModules takes care of registering a map of paths that a plugin exposes so they can be
+// loaded from the JavaScript VM.
+func RegisterPluginModules(modules map[string]interface{}) {
+	for path, impl := range modules {
+		importPath := fmt.Sprintf("k6-plugin/%s", path)
+		PluginIndex[importPath] = impl
+	}
+}
diff --git a/lib/options_test.go b/lib/options_test.go
index c7d86928636..28c5368a161 100644
--- a/lib/options_test.go
+++ b/lib/options_test.go
@@ -476,6 +476,11 @@ func TestOptionsEnv(t *testing.T) {
 			"true":  null.BoolFrom(true),
 			"false": null.BoolFrom(false),
 		},
+		{"Plugins", "K6_PLUGINS"}: {
+			"":              []string{},
+			"foo.so":        []string{"foo.so"},
+			"foo.so,bar.so": []string{"foo.so", "bar.so"},
+		},
 		// Thresholds
 		// External
 	}
diff --git a/lib/plugin.go b/lib/plugin.go
index f5b94e61f6c..e46e2f7c749 100644
--- a/lib/plugin.go
+++ b/lib/plugin.go
@@ -7,6 +7,8 @@ import (
 	"github.com/loadimpact/k6/plugin"
 )
 
+// LoadJavaScriptPlugin tries to load a dynamic library that should conform to
+// the `plug.JavaScriptPlugin` interface.
 func LoadJavaScriptPlugin(path string) (plugin.JavaScriptPlugin, error) {
 	p, err := loadPlugin(path)
 	if err != nil {
@@ -28,7 +30,9 @@ func LoadJavaScriptPlugin(path string) (plugin.JavaScriptPlugin, error) {
 }
 
 func loadPlugin(path string) (*goplugin.Plugin, error) {
-	// TODO: check for things like the file existing and return nicer errors
 	p, err := goplugin.Open(path)
+	if err != nil {
+		err = fmt.Errorf("error while loading plugin: %w", err)
+	}
 	return p, err
 }
diff --git a/plugin/plugin.go b/plugin/plugin.go
index 35085e1aeae..1d43ae0be7b 100644
--- a/plugin/plugin.go
+++ b/plugin/plugin.go
@@ -20,7 +20,7 @@
 
 package plugin
 
-// A Plugin ...
+// A Plugin is used to extend the javascript VM with functionality implemented in Golang.
 type Plugin interface {
 	// Returns a user-friendly name for the plugin.
 	Name() string
@@ -32,6 +32,7 @@ type Plugin interface {
 	Teardown() error
 }
 
+// A JavaScriptPlugin represents a binding between code that can run in the JavaScript VM and Golang.
 type JavaScriptPlugin interface {
 	Plugin
 

From 4b984b5449eef8b471b30d84f2ae52e830043359 Mon Sep 17 00:00:00 2001
From: Andre Medeiros <me@andremedeiros.info>
Date: Thu, 16 Apr 2020 20:47:03 -0400
Subject: [PATCH 05/16] add copyright header to lib/plugin.go

---
 lib/plugin.go | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/lib/plugin.go b/lib/plugin.go
index e46e2f7c749..0833bb00cec 100644
--- a/lib/plugin.go
+++ b/lib/plugin.go
@@ -1,3 +1,23 @@
+/*
+ *
+ * k6 - a next-generation load testing tool
+ * Copyright (C) 2016 Load Impact
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
 package lib
 
 import (

From 86aeafa3337b62c6bd5d3942a662aed4665f993d Mon Sep 17 00:00:00 2001
From: Andre Medeiros <me@andremedeiros.info>
Date: Thu, 16 Apr 2020 20:53:20 -0400
Subject: [PATCH 06/16] ci fix

---
 .circleci/config.yml | 1 +
 Makefile             | 1 +
 2 files changed, 2 insertions(+)

diff --git a/.circleci/config.yml b/.circleci/config.yml
index 642ebe4fc4c..e929e4aeb5a 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -69,6 +69,7 @@ jobs:
           command: |
             go version
             pushd /tmp
+            go get -d github.com/andremedeiros/leftpad
             go build -buildmode=plugin -o /tmp/leftpad.so github.com/andremedeiros/leftpad
             popd
       - run:
diff --git a/Makefile b/Makefile
index 9d145d6eedb..d7c2f26b650 100644
--- a/Makefile
+++ b/Makefile
@@ -12,6 +12,7 @@ format:
 
 .PHONY: plugin
 plugin:
+	pushd /tmp; go get -d github.com/andremedeiros/leftpad; popd
 	pushd /tmp; go build -buildmode=plugin -o /tmp/leftpad.so github.com/andremedeiros/leftpad; popd
 
 .PHONY: check

From 946f88cbb3ce684bef089fd8c0d69c70f587a8af Mon Sep 17 00:00:00 2001
From: Andre Medeiros <me@andremedeiros.info>
Date: Thu, 16 Apr 2020 21:04:38 -0400
Subject: [PATCH 07/16] another attempt at fixing ci

---
 .circleci/config.yml | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/.circleci/config.yml b/.circleci/config.yml
index e929e4aeb5a..9e3fa3e66c7 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -66,12 +66,13 @@ jobs:
       - checkout
       - run:
           name: Build plugin artifact for tests
+          working_directory: /tmp
           command: |
             go version
-            pushd /tmp
+            export GOMAXPROCS=2
+            export PATH=$GOPATH/bin:$PATH
             go get -d github.com/andremedeiros/leftpad
             go build -buildmode=plugin -o /tmp/leftpad.so github.com/andremedeiros/leftpad
-            popd
       - run:
           name: Run tests and code coverage
           command: |
@@ -100,6 +101,15 @@ jobs:
     working_directory: /home/circleci/.go_workspace/src/github.com/loadimpact/k6
     steps:
       - checkout
+      - run:
+          name: Build plugin artifact for tests
+          working_directory: /tmp
+          command: |
+            go version
+            export GOMAXPROCS=2
+            export PATH=$GOPATH/bin:$PATH
+            go get -d github.com/andremedeiros/leftpad
+            go build -buildmode=plugin -o /tmp/leftpad.so github.com/andremedeiros/leftpad
       - run:
           name: Run tests with previous Go version
           command: |

From a82e894d0d26b2eaf90cd1d046d95362d00d11cd Mon Sep 17 00:00:00 2001
From: Andre Medeiros <me@andremedeiros.info>
Date: Thu, 16 Apr 2020 21:10:25 -0400
Subject: [PATCH 08/16] fix test assertion

---
 js/initcontext_test.go | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/js/initcontext_test.go b/js/initcontext_test.go
index 8a6cd04e0d5..c5d63651a22 100644
--- a/js/initcontext_test.go
+++ b/js/initcontext_test.go
@@ -238,7 +238,9 @@ func TestInitContextRequire(t *testing.T) {
 	t.Run("Plugins", func(t *testing.T) {
 		t.Run("leftpad", func(t *testing.T) {
 			plugin, err := lib.LoadJavaScriptPlugin("/tmp/leftpad.so")
-			assert.NoError(t, err)
+			if !assert.NoError(t, err) {
+				return
+			}
 			assert.Equal(t, "Leftpad", plugin.Name())
 
 			modules.RegisterPluginModules(plugin.GetModules())

From af0ae4a4f6bb52879bfb8ff39c1d826e25e69eca Mon Sep 17 00:00:00 2001
From: Andre Medeiros <me@andremedeiros.info>
Date: Sat, 9 May 2020 17:09:35 -0400
Subject: [PATCH 09/16] revert circleci changes

---
 .circleci/config.yml | 18 ------------------
 1 file changed, 18 deletions(-)

diff --git a/.circleci/config.yml b/.circleci/config.yml
index 9e3fa3e66c7..f13908db9bd 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -64,15 +64,6 @@ jobs:
     working_directory: /home/circleci/.go_workspace/src/github.com/loadimpact/k6
     steps:
       - checkout
-      - run:
-          name: Build plugin artifact for tests
-          working_directory: /tmp
-          command: |
-            go version
-            export GOMAXPROCS=2
-            export PATH=$GOPATH/bin:$PATH
-            go get -d github.com/andremedeiros/leftpad
-            go build -buildmode=plugin -o /tmp/leftpad.so github.com/andremedeiros/leftpad
       - run:
           name: Run tests and code coverage
           command: |
@@ -101,15 +92,6 @@ jobs:
     working_directory: /home/circleci/.go_workspace/src/github.com/loadimpact/k6
     steps:
       - checkout
-      - run:
-          name: Build plugin artifact for tests
-          working_directory: /tmp
-          command: |
-            go version
-            export GOMAXPROCS=2
-            export PATH=$GOPATH/bin:$PATH
-            go get -d github.com/andremedeiros/leftpad
-            go build -buildmode=plugin -o /tmp/leftpad.so github.com/andremedeiros/leftpad
       - run:
           name: Run tests with previous Go version
           command: |

From dcc2a42c2d29a47bc1970669eac6f5286ebbd183 Mon Sep 17 00:00:00 2001
From: Andre Medeiros <me@andremedeiros.info>
Date: Sat, 9 May 2020 17:09:46 -0400
Subject: [PATCH 10/16] revert makefile changes

---
 Makefile | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/Makefile b/Makefile
index d7c2f26b650..c10bd275222 100644
--- a/Makefile
+++ b/Makefile
@@ -10,13 +10,8 @@ build:
 format:
 	find . -name '*.go' -exec gofmt -s -w {} +
 
-.PHONY: plugin
-plugin:
-	pushd /tmp; go get -d github.com/andremedeiros/leftpad; popd
-	pushd /tmp; go build -buildmode=plugin -o /tmp/leftpad.so github.com/andremedeiros/leftpad; popd
-
 .PHONY: check
-check: plugin
+check:
 	golangci-lint run --out-format=tab --new-from-rev master ./...
 	go test -race -timeout 210s ./...
 

From aecb2812e6a7aaf69d149fc3be9c02e1371ca8fd Mon Sep 17 00:00:00 2001
From: Andre Medeiros <me@andremedeiros.info>
Date: Sat, 9 May 2020 17:09:57 -0400
Subject: [PATCH 11/16] shuffle some code around

---
 js/initcontext_test.go     | 23 +++++++++++++++++++-
 lib/plugin_windows.go      | 31 +++++++++++++++++++++++++++
 samples/leftpad/leftpad.go | 44 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 97 insertions(+), 1 deletion(-)
 create mode 100644 lib/plugin_windows.go
 create mode 100644 samples/leftpad/leftpad.go

diff --git a/js/initcontext_test.go b/js/initcontext_test.go
index c5d63651a22..126f0dafb31 100644
--- a/js/initcontext_test.go
+++ b/js/initcontext_test.go
@@ -27,7 +27,10 @@ import (
 	"net"
 	"net/http"
 	"net/http/httptest"
+	"os"
+	"os/exec"
 	"path/filepath"
+	"runtime"
 	"testing"
 	"time"
 
@@ -236,8 +239,26 @@ func TestInitContextRequire(t *testing.T) {
 	})
 
 	t.Run("Plugins", func(t *testing.T) {
+		if runtime.GOOS == "windows" {
+			t.Skip("skipping test due to lack of plugin support in windows")
+			return
+		}
+
 		t.Run("leftpad", func(t *testing.T) {
-			plugin, err := lib.LoadJavaScriptPlugin("/tmp/leftpad.so")
+			tf, err := ioutil.TempFile("", "leftpad.so")
+			if !assert.NoError(t, err, "temporary file error") {
+				return
+			}
+			defer os.Remove(tf.Name())
+
+			// go build -buildmode=plugin -o /tmp/leftpad.so
+			cmd := exec.Command("go", "build", "-buildmode=plugin", "-o", tf.Name(), "github.com/loadimpact/k6/samples/leftpad")
+			err = cmd.Run()
+			if !assert.NoError(t, err, "compiling sample plugin error") {
+				return
+			}
+
+			plugin, err := lib.LoadJavaScriptPlugin(tf.Name())
 			if !assert.NoError(t, err) {
 				return
 			}
diff --git a/lib/plugin_windows.go b/lib/plugin_windows.go
new file mode 100644
index 00000000000..d3f01fe2eba
--- /dev/null
+++ b/lib/plugin_windows.go
@@ -0,0 +1,31 @@
+/*
+ *
+ * k6 - a next-generation load testing tool
+ * Copyright (C) 2016 Load Impact
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+package lib
+
+import (
+	"github.com/loadimpact/k6/plugin"
+	"github.com/pkg/errors"
+)
+
+// LoadJavaScriptPlugin does not work on Windows, so it always returns an error.
+func LoadJavaScriptPlugin(path string) (plugin.JavaScriptPlugin, error) {
+	return nil, errors.New("plugins are not supported in Windows")
+}
diff --git a/samples/leftpad/leftpad.go b/samples/leftpad/leftpad.go
new file mode 100644
index 00000000000..156589d61d5
--- /dev/null
+++ b/samples/leftpad/leftpad.go
@@ -0,0 +1,44 @@
+package main
+
+import "strings"
+
+type leftpad struct{}
+
+func New() *leftpad {
+	return &leftpad{}
+}
+
+func (*leftpad) Leftpad(s string, l int, padding string) string {
+	if len(s) >= l {
+		return s
+	}
+
+	return strings.Repeat(padding, l-len(s)) + s
+}
+
+type plugin struct{}
+
+var JavaScriptPlugin plugin
+
+func (*plugin) Name() string {
+	return "Leftpad"
+}
+
+func (*plugin) Setup() error {
+	return nil
+}
+
+func (*plugin) Teardown() error {
+	return nil
+}
+
+func (*plugin) GetModules() map[string]interface{} {
+	mods := map[string]interface{}{
+		"leftpad": New(),
+	}
+	return mods
+}
+
+func init() {
+	JavaScriptPlugin = plugin{}
+}

From 4f36ff091aeace03897aaa65cd55e397176eb913 Mon Sep 17 00:00:00 2001
From: Andre Medeiros <me@andremedeiros.info>
Date: Sat, 9 May 2020 17:35:22 -0400
Subject: [PATCH 12/16] run js setup in a parallel group

---
 Gopkg.lock                                    |  9 +++
 cmd/run.go                                    | 22 +++++--
 samples/leftpad/leftpad.go                    |  7 +-
 vendor/golang.org/x/sync/AUTHORS              |  3 +
 vendor/golang.org/x/sync/CONTRIBUTORS         |  3 +
 vendor/golang.org/x/sync/LICENSE              | 27 ++++++++
 vendor/golang.org/x/sync/PATENTS              | 22 +++++++
 vendor/golang.org/x/sync/errgroup/errgroup.go | 66 +++++++++++++++++++
 8 files changed, 147 insertions(+), 12 deletions(-)
 create mode 100644 vendor/golang.org/x/sync/AUTHORS
 create mode 100644 vendor/golang.org/x/sync/CONTRIBUTORS
 create mode 100644 vendor/golang.org/x/sync/LICENSE
 create mode 100644 vendor/golang.org/x/sync/PATENTS
 create mode 100644 vendor/golang.org/x/sync/errgroup/errgroup.go

diff --git a/Gopkg.lock b/Gopkg.lock
index 2243c01a8ac..e5294c818e1 100644
--- a/Gopkg.lock
+++ b/Gopkg.lock
@@ -604,6 +604,14 @@
   pruneopts = "NUT"
   revision = "351d144fa1fc0bd934e2408202be0c29f25e35a0"
 
+[[projects]]
+  branch = "master"
+  digest = "1:b521f10a2d8fa85c04a8ef4e62f2d1e14d303599a55d64dabf9f5a02f84d35eb"
+  name = "golang.org/x/sync"
+  packages = ["errgroup"]
+  pruneopts = "NUT"
+  revision = "43a5402ce75a95522677f77c619865d66b8c57ab"
+
 [[projects]]
   branch = "master"
   digest = "1:b1a955501003b967a2c814e41ded50c7b29dfdeb7f266b7987b8ed38f65205d6"
@@ -722,6 +730,7 @@
     "golang.org/x/crypto/ssh/terminal",
     "golang.org/x/net/html",
     "golang.org/x/net/http2",
+    "golang.org/x/sync/errgroup",
     "golang.org/x/text/unicode/norm",
     "golang.org/x/time/rate",
     "gopkg.in/guregu/null.v3",
diff --git a/cmd/run.go b/cmd/run.go
index 29c6a1fb1d9..75f40c52e6a 100644
--- a/cmd/run.go
+++ b/cmd/run.go
@@ -39,6 +39,7 @@ import (
 	"github.com/spf13/afero"
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
+	"golang.org/x/sync/errgroup"
 	null "gopkg.in/guregu/null.v3"
 
 	"github.com/loadimpact/k6/api"
@@ -115,24 +116,31 @@ a commandline interface for interacting with it.`,
 			return err
 		}
 
+		g, _ := errgroup.WithContext(context.Background())
+		if err != nil {
+			return err
+		}
+
 		plugins := []plugin.JavaScriptPlugin{}
 		pluginNames := []string{}
 		for _, pluginPath := range cliConf.Plugins {
-			jsPlugin, err := lib.LoadJavaScriptPlugin(pluginPath)
-			if err != nil {
-				return err
+			jsPlugin, pluginErr := lib.LoadJavaScriptPlugin(pluginPath)
+			if pluginErr != nil {
+				return pluginErr
 			}
 
-			// Run plugin setup and add it to the module tree
-			if err = jsPlugin.Setup(); err != nil {
-				return err
-			}
+			// Do the part that actually takes time in a runner group.
+			g.Go(jsPlugin.Setup)
 
 			modules.RegisterPluginModules(jsPlugin.GetModules())
 			plugins = append(plugins, jsPlugin)
 			pluginNames = append(pluginNames, jsPlugin.Name())
 		}
 
+		if err = g.Wait(); err != nil {
+			return err
+		}
+
 		// Create the Runner.
 		fprintf(stdout, "%s runner\r", initBar.String())
 		pwd, err := os.Getwd()
diff --git a/samples/leftpad/leftpad.go b/samples/leftpad/leftpad.go
index 156589d61d5..48e5470874f 100644
--- a/samples/leftpad/leftpad.go
+++ b/samples/leftpad/leftpad.go
@@ -4,10 +4,6 @@ import "strings"
 
 type leftpad struct{}
 
-func New() *leftpad {
-	return &leftpad{}
-}
-
 func (*leftpad) Leftpad(s string, l int, padding string) string {
 	if len(s) >= l {
 		return s
@@ -34,11 +30,12 @@ func (*plugin) Teardown() error {
 
 func (*plugin) GetModules() map[string]interface{} {
 	mods := map[string]interface{}{
-		"leftpad": New(),
+		"leftpad": &leftpad{},
 	}
 	return mods
 }
 
 func init() {
 	JavaScriptPlugin = plugin{}
+	_ = JavaScriptPlugin // shut up, linter...
 }
diff --git a/vendor/golang.org/x/sync/AUTHORS b/vendor/golang.org/x/sync/AUTHORS
new file mode 100644
index 00000000000..15167cd746c
--- /dev/null
+++ b/vendor/golang.org/x/sync/AUTHORS
@@ -0,0 +1,3 @@
+# This source code refers to The Go Authors for copyright purposes.
+# The master list of authors is in the main Go distribution,
+# visible at http://tip.golang.org/AUTHORS.
diff --git a/vendor/golang.org/x/sync/CONTRIBUTORS b/vendor/golang.org/x/sync/CONTRIBUTORS
new file mode 100644
index 00000000000..1c4577e9680
--- /dev/null
+++ b/vendor/golang.org/x/sync/CONTRIBUTORS
@@ -0,0 +1,3 @@
+# This source code was written by the Go contributors.
+# The master list of contributors is in the main Go distribution,
+# visible at http://tip.golang.org/CONTRIBUTORS.
diff --git a/vendor/golang.org/x/sync/LICENSE b/vendor/golang.org/x/sync/LICENSE
new file mode 100644
index 00000000000..6a66aea5eaf
--- /dev/null
+++ b/vendor/golang.org/x/sync/LICENSE
@@ -0,0 +1,27 @@
+Copyright (c) 2009 The Go Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/vendor/golang.org/x/sync/PATENTS b/vendor/golang.org/x/sync/PATENTS
new file mode 100644
index 00000000000..733099041f8
--- /dev/null
+++ b/vendor/golang.org/x/sync/PATENTS
@@ -0,0 +1,22 @@
+Additional IP Rights Grant (Patents)
+
+"This implementation" means the copyrightable works distributed by
+Google as part of the Go project.
+
+Google hereby grants to You a perpetual, worldwide, non-exclusive,
+no-charge, royalty-free, irrevocable (except as stated in this section)
+patent license to make, have made, use, offer to sell, sell, import,
+transfer and otherwise run, modify and propagate the contents of this
+implementation of Go, where such license applies only to those patent
+claims, both currently owned or controlled by Google and acquired in
+the future, licensable by Google that are necessarily infringed by this
+implementation of Go.  This grant does not include claims that would be
+infringed only as a consequence of further modification of this
+implementation.  If you or your agent or exclusive licensee institute or
+order or agree to the institution of patent litigation against any
+entity (including a cross-claim or counterclaim in a lawsuit) alleging
+that this implementation of Go or any code incorporated within this
+implementation of Go constitutes direct or contributory patent
+infringement, or inducement of patent infringement, then any patent
+rights granted to you under this License for this implementation of Go
+shall terminate as of the date such litigation is filed.
diff --git a/vendor/golang.org/x/sync/errgroup/errgroup.go b/vendor/golang.org/x/sync/errgroup/errgroup.go
new file mode 100644
index 00000000000..9857fe53d3c
--- /dev/null
+++ b/vendor/golang.org/x/sync/errgroup/errgroup.go
@@ -0,0 +1,66 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package errgroup provides synchronization, error propagation, and Context
+// cancelation for groups of goroutines working on subtasks of a common task.
+package errgroup
+
+import (
+	"context"
+	"sync"
+)
+
+// A Group is a collection of goroutines working on subtasks that are part of
+// the same overall task.
+//
+// A zero Group is valid and does not cancel on error.
+type Group struct {
+	cancel func()
+
+	wg sync.WaitGroup
+
+	errOnce sync.Once
+	err     error
+}
+
+// WithContext returns a new Group and an associated Context derived from ctx.
+//
+// The derived Context is canceled the first time a function passed to Go
+// returns a non-nil error or the first time Wait returns, whichever occurs
+// first.
+func WithContext(ctx context.Context) (*Group, context.Context) {
+	ctx, cancel := context.WithCancel(ctx)
+	return &Group{cancel: cancel}, ctx
+}
+
+// Wait blocks until all function calls from the Go method have returned, then
+// returns the first non-nil error (if any) from them.
+func (g *Group) Wait() error {
+	g.wg.Wait()
+	if g.cancel != nil {
+		g.cancel()
+	}
+	return g.err
+}
+
+// Go calls the given function in a new goroutine.
+//
+// The first call to return a non-nil error cancels the group; its error will be
+// returned by Wait.
+func (g *Group) Go(f func() error) {
+	g.wg.Add(1)
+
+	go func() {
+		defer g.wg.Done()
+
+		if err := f(); err != nil {
+			g.errOnce.Do(func() {
+				g.err = err
+				if g.cancel != nil {
+					g.cancel()
+				}
+			})
+		}
+	}()
+}

From bea978a97088902c5221cb0c009ed5cc7cfcc2d9 Mon Sep 17 00:00:00 2001
From: Andre Medeiros <me@andremedeiros.info>
Date: Sat, 9 May 2020 17:44:17 -0400
Subject: [PATCH 13/16] shuffle test helper around some

---
 js/initcontext_test.go | 26 +++++++++++++++-----------
 js/modules/index.go    |  2 +-
 2 files changed, 16 insertions(+), 12 deletions(-)

diff --git a/js/initcontext_test.go b/js/initcontext_test.go
index 126f0dafb31..462931ae5c8 100644
--- a/js/initcontext_test.go
+++ b/js/initcontext_test.go
@@ -30,7 +30,6 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
-	"runtime"
 	"testing"
 	"time"
 
@@ -48,6 +47,15 @@ import (
 	"github.com/loadimpact/k6/stats"
 )
 
+func getTemporaryFile(name string) (string, func()) {
+	tf, _ := ioutil.TempFile("", name)
+	cleanup := func() {
+		_ = os.Remove(tf.Name())
+	}
+
+	return tf.Name(), cleanup
+}
+
 func TestInitContextRequire(t *testing.T) {
 	t.Run("Modules", func(t *testing.T) {
 		t.Run("Nonexistent", func(t *testing.T) {
@@ -239,26 +247,22 @@ func TestInitContextRequire(t *testing.T) {
 	})
 
 	t.Run("Plugins", func(t *testing.T) {
-		if runtime.GOOS == "windows" {
+		if isWindows {
 			t.Skip("skipping test due to lack of plugin support in windows")
 			return
 		}
 
 		t.Run("leftpad", func(t *testing.T) {
-			tf, err := ioutil.TempFile("", "leftpad.so")
-			if !assert.NoError(t, err, "temporary file error") {
-				return
-			}
-			defer os.Remove(tf.Name())
+			path, cleanup := getTemporaryFile("leftpad.so")
+			defer cleanup()
 
 			// go build -buildmode=plugin -o /tmp/leftpad.so
-			cmd := exec.Command("go", "build", "-buildmode=plugin", "-o", tf.Name(), "github.com/loadimpact/k6/samples/leftpad")
-			err = cmd.Run()
-			if !assert.NoError(t, err, "compiling sample plugin error") {
+			cmd := exec.Command("go", "build", "-buildmode=plugin", "-o", path, "github.com/loadimpact/k6/samples/leftpad")
+			if err := cmd.Run(); !assert.NoError(t, err, "compiling sample plugin error") {
 				return
 			}
 
-			plugin, err := lib.LoadJavaScriptPlugin(tf.Name())
+			plugin, err := lib.LoadJavaScriptPlugin(path)
 			if !assert.NoError(t, err) {
 				return
 			}
diff --git a/js/modules/index.go b/js/modules/index.go
index 1ddeb008005..6327e522615 100644
--- a/js/modules/index.go
+++ b/js/modules/index.go
@@ -45,7 +45,7 @@ var Index = map[string]interface{}{
 	"k6/ws":          ws.New(),
 }
 
-// PluginIndex holds a map of plugin modules to their respective implementations.
+// PluginIndex holds an index of plugin module implementations.
 var PluginIndex = map[string]interface{}{}
 
 // RegisterPluginModules takes care of registering a map of paths that a plugin exposes so they can be

From b93869324ff0f4ed1af80303de236c39bc109628 Mon Sep 17 00:00:00 2001
From: Andre Medeiros <me@andremedeiros.info>
Date: Sat, 9 May 2020 17:49:43 -0400
Subject: [PATCH 14/16] add build flag to plugin file

---
 lib/plugin.go | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/plugin.go b/lib/plugin.go
index 0833bb00cec..22e4e013821 100644
--- a/lib/plugin.go
+++ b/lib/plugin.go
@@ -1,3 +1,4 @@
+// +build !windows
 /*
  *
  * k6 - a next-generation load testing tool

From a43fe5dd8933b0542d8ad101b9254ea7e41c5cc9 Mon Sep 17 00:00:00 2001
From: Andre Medeiros <me@andremedeiros.info>
Date: Sat, 9 May 2020 17:57:13 -0400
Subject: [PATCH 15/16] turns out file suffixes dont work as i thought

---
 lib/plugin.go         |  7 ++++++-
 lib/plugin_windows.go | 31 -------------------------------
 2 files changed, 6 insertions(+), 32 deletions(-)
 delete mode 100644 lib/plugin_windows.go

diff --git a/lib/plugin.go b/lib/plugin.go
index 22e4e013821..5d40fc091fb 100644
--- a/lib/plugin.go
+++ b/lib/plugin.go
@@ -1,4 +1,3 @@
-// +build !windows
 /*
  *
  * k6 - a next-generation load testing tool
@@ -24,8 +23,10 @@ package lib
 import (
 	"fmt"
 	goplugin "plugin"
+	"runtime"
 
 	"github.com/loadimpact/k6/plugin"
+	"github.com/pkg/errors"
 )
 
 // LoadJavaScriptPlugin tries to load a dynamic library that should conform to
@@ -51,6 +52,10 @@ func LoadJavaScriptPlugin(path string) (plugin.JavaScriptPlugin, error) {
 }
 
 func loadPlugin(path string) (*goplugin.Plugin, error) {
+	if runtime.GOOS == "windows" {
+		return nil, errors.New("plugins are not supported in Windows")
+	}
+
 	p, err := goplugin.Open(path)
 	if err != nil {
 		err = fmt.Errorf("error while loading plugin: %w", err)
diff --git a/lib/plugin_windows.go b/lib/plugin_windows.go
deleted file mode 100644
index d3f01fe2eba..00000000000
--- a/lib/plugin_windows.go
+++ /dev/null
@@ -1,31 +0,0 @@
-/*
- *
- * k6 - a next-generation load testing tool
- * Copyright (C) 2016 Load Impact
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as
- * published by the Free Software Foundation, either version 3 of the
- * License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- *
- * You should have received a copy of the GNU Affero General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- */
-
-package lib
-
-import (
-	"github.com/loadimpact/k6/plugin"
-	"github.com/pkg/errors"
-)
-
-// LoadJavaScriptPlugin does not work on Windows, so it always returns an error.
-func LoadJavaScriptPlugin(path string) (plugin.JavaScriptPlugin, error) {
-	return nil, errors.New("plugins are not supported in Windows")
-}

From 9dbc2f9ff3d7dbceeb6f06c58b81dcfda3fb3243 Mon Sep 17 00:00:00 2001
From: Andre Medeiros <me@andremedeiros.info>
Date: Sat, 9 May 2020 19:49:19 -0400
Subject: [PATCH 16/16] add race detector so plugin matches platform

---
 js/initcontext_test.go      | 9 +++++++--
 testhelpers/israce/race.go  | 7 +++++++
 testhelpers/israce/race0.go | 7 +++++++
 3 files changed, 21 insertions(+), 2 deletions(-)
 create mode 100644 testhelpers/israce/race.go
 create mode 100644 testhelpers/israce/race0.go

diff --git a/js/initcontext_test.go b/js/initcontext_test.go
index 462931ae5c8..c7895b94b5b 100644
--- a/js/initcontext_test.go
+++ b/js/initcontext_test.go
@@ -45,6 +45,7 @@ import (
 	"github.com/loadimpact/k6/lib"
 	"github.com/loadimpact/k6/lib/netext"
 	"github.com/loadimpact/k6/stats"
+	"github.com/loadimpact/k6/testhelpers/israce"
 )
 
 func getTemporaryFile(name string) (string, func()) {
@@ -256,8 +257,12 @@ func TestInitContextRequire(t *testing.T) {
 			path, cleanup := getTemporaryFile("leftpad.so")
 			defer cleanup()
 
-			// go build -buildmode=plugin -o /tmp/leftpad.so
-			cmd := exec.Command("go", "build", "-buildmode=plugin", "-o", path, "github.com/loadimpact/k6/samples/leftpad")
+			args := []string{"build", "-buildmode=plugin", "-o", path}
+			if israce.Enabled {
+				args = append(args, "-race")
+			}
+			args = append(args, "github.com/loadimpact/k6/samples/leftpad")
+			cmd := exec.Command("go", args...)
 			if err := cmd.Run(); !assert.NoError(t, err, "compiling sample plugin error") {
 				return
 			}
diff --git a/testhelpers/israce/race.go b/testhelpers/israce/race.go
new file mode 100644
index 00000000000..498981efef3
--- /dev/null
+++ b/testhelpers/israce/race.go
@@ -0,0 +1,7 @@
+// +build race
+
+// Package israce reports if the Go race detector is enabled.
+package israce
+
+// Enabled reports if the race detector is enabled.
+const Enabled = true
diff --git a/testhelpers/israce/race0.go b/testhelpers/israce/race0.go
new file mode 100644
index 00000000000..570dc13a282
--- /dev/null
+++ b/testhelpers/israce/race0.go
@@ -0,0 +1,7 @@
+// +build !race
+
+// Package israce reports if the Go race detector is enabled.
+package israce
+
+// Enabled reports if the race detector is enabled.
+const Enabled = false