Refactor isRemoteBrowser check

browser/mapping.go

@@ -4,13 +4,11 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"os"
 
 	"github.com/dop251/goja"
 
 	"github.com/grafana/xk6-browser/api"
 	"github.com/grafana/xk6-browser/chromium"
-	"github.com/grafana/xk6-browser/env"
 	"github.com/grafana/xk6-browser/k6error"
 	"github.com/grafana/xk6-browser/k6ext"
 
@@ -37,7 +35,7 @@ func mapBrowserToGoja(vu moduleVU) *goja.Object {
 		obj = rt.NewObject()
 		// TODO: Use k6 LookupEnv instead of OS package methods.
 		// See https://github.com/grafana/xk6-browser/issues/822.
-		wsURL, isRemoteBrowser = env.IsRemoteBrowser(os.LookupEnv)
+		wsURL, isRemoteBrowser = vu.remoteRegistry.IsRemoteBrowser()
 		browserType            = chromium.NewBrowserType(vu)
 	)
 	for k, v := range mapBrowserType(vu, browserType, wsURL, isRemoteBrowser) {

browser/module.go

@@ -2,9 +2,12 @@
 package browser
 
 import (
+	"os"
+
 	"github.com/dop251/goja"
 
 	"github.com/grafana/xk6-browser/common"
+	"github.com/grafana/xk6-browser/registry"
 
 	k6modules "go.k6.io/k6/js/modules"
 )
@@ -13,7 +16,8 @@ type (
 	// RootModule is the global module instance that will create module
 	// instances for each VU.
 	RootModule struct {
-		PidRegistry *pidRegistry
+		PidRegistry    *pidRegistry
+		remoteRegistry *registry.RemoteRegistry
 	}
 
 	// JSModule exposes the properties available to the JS script.
@@ -37,7 +41,8 @@ var (
 // New returns a pointer to a new RootModule instance.
 func New() *RootModule {
 	return &RootModule{
-		PidRegistry: &pidRegistry{},
+		PidRegistry:    &pidRegistry{},
+		remoteRegistry: registry.NewRemoteRegistry(os.LookupEnv),
 	}
 }
 
@@ -47,8 +52,9 @@ func (m *RootModule) NewModuleInstance(vu k6modules.VU) k6modules.Instance {
 	return &ModuleInstance{
 		mod: &JSModule{
 			Chromium: mapBrowserToGoja(moduleVU{
-				VU:          vu,
-				pidRegistry: m.PidRegistry,
+				VU:             vu,
+				pidRegistry:    m.PidRegistry,
+				remoteRegistry: m.remoteRegistry,
 			}),
 			Devices: common.GetDevices(),
 		},

browser/modulevu.go

@@ -4,6 +4,7 @@ import (
 	"context"
 
 	"github.com/grafana/xk6-browser/k6ext"
+	"github.com/grafana/xk6-browser/registry"
 
 	k6modules "go.k6.io/k6/js/modules"
 )
@@ -16,6 +17,7 @@ type moduleVU struct {
 	k6modules.VU
 
 	*pidRegistry
+	remoteRegistry *registry.RemoteRegistry
 }
 
 func (vu moduleVU) Context() context.Context {

env/env.go

@@ -1,41 +1,5 @@
+// Package env provides types to interact with environment setup.
 package env
 
-import (
-	"crypto/rand"
-	"math/big"
-	"strings"
-)
-
 // LookupFunc defines a function to look up a key from the environment.
 type LookupFunc func(key string) (string, bool)
-
-// IsRemoteBrowser returns true and the corresponding CDP
-// WS URL if this one is set through the K6_BROWSER_WS_URL
-// environment variable. Otherwise returns false.
-// If K6_BROWSER_WS_URL is set as a comma separated list of
-// URLs, this method returns a randomly chosen URL from the list
-// so connections are done in a round-robin fashion for all the
-// entries in the list.
-func IsRemoteBrowser(envLookup LookupFunc) (wsURL string, isRemote bool) {
-	wsURL, isRemote = envLookup("K6_BROWSER_WS_URL")
-	if !isRemote {
-		return "", false
-	}
-	if !strings.ContainsRune(wsURL, ',') {
-		return wsURL, isRemote
-	}
-
-	// If last parts element is a void string,
-	// because WS URL contained an ending comma,
-	// remove it
-	parts := strings.Split(wsURL, ",")
-	if parts[len(parts)-1] == "" {
-		parts = parts[:len(parts)-1]
-	}
-
-	// Choose a random WS URL from the provided list
-	i, _ := rand.Int(rand.Reader, big.NewInt(int64(len(parts))))
-	wsURL = parts[i.Int64()]
-
-	return wsURL, isRemote
-}

examples/multiple-scenario.js

@@ -27,7 +27,7 @@ export const options = {
     },
   },
   thresholds: {
-    webvital_first_contentful_paint: ['max < 1000'],
+    browser_web_vital_fcp: ['max < 1000'],
     checks: ["rate==1.0"]
   }
 }

k6ext/metrics.go

@@ -24,12 +24,12 @@ type CustomMetrics struct {
 // VU Registry and returns our internal struct pointer.
 func RegisterCustomMetrics(registry *k6metrics.Registry) *CustomMetrics {
 	wvs := map[string]string{
-		webVitalFID:  "webvital_first_input_delay",
-		webVitalTTFB: "webvital_time_to_first_byte",
-		webVitalLCP:  "webvital_largest_content_paint",
-		webVitalCLS:  "webvital_cumulative_layout_shift",
-		webVitalINP:  "webvital_interaction_to_next_paint",
-		webVitalFCP:  "webvital_first_contentful_paint",
+		webVitalFID:  "browser_web_vital_fid",  // first input delay
+		webVitalTTFB: "browser_web_vital_ttfb", // time to first byte
+		webVitalLCP:  "browser_web_vital_lcp",  // largest content paint
+		webVitalCLS:  "browser_web_vital_cls",  // cumulative layout shift
+		webVitalINP:  "browser_web_vital_inp",  // interaction to next paint
+		webVitalFCP:  "browser_web_vital_fcp",  // first contentful paint
 	}
 	webVitals := make(map[string]*k6metrics.Metric)
 

registry/doc.go

@@ -0,0 +1,3 @@
+// Package registry provides types and methods that store
+// information that currently span the whole test run.
+package registry

registry/remote.go

@@ -0,0 +1,66 @@
+package registry
+
+import (
+	"crypto/rand"
+	"math/big"
+	"strings"
+
+	"github.com/grafana/xk6-browser/env"
+)
+
+// RemoteRegistry contains the details of the remote web browsers.
+// At the moment it's the WS URLs.
+type RemoteRegistry struct {
+	isRemoteBrowser bool
+	wsURLs          []string
+}
+
+// NewRemoteRegistry will create a new RemoteRegistry. This will
+// parse the K6_BROWSER_WS_URL env var to retrieve the defined
+// list of WS URLs.
+//
+// K6_BROWSER_WS_URL can be defined as a single WS URL or a
+// comma separated list of URLs.
+func NewRemoteRegistry(envLookup env.LookupFunc) *RemoteRegistry {
+	r := &RemoteRegistry{}
+
+	wsURL, isRemote := envLookup("K6_BROWSER_WS_URL")
+	if !isRemote {
+		return r
+	}
+
+	if !strings.ContainsRune(wsURL, ',') {
+		r.isRemoteBrowser = true
+		r.wsURLs = []string{wsURL}
+		return r
+	}
+
+	// If last parts element is a void string,
+	// because WS URL contained an ending comma,
+	// remove it
+	parts := strings.Split(wsURL, ",")
+	if parts[len(parts)-1] == "" {
+		parts = parts[:len(parts)-1]
+	}
+
+	r.isRemoteBrowser = true
+	r.wsURLs = parts
+
+	return r
+}
+
+// IsRemoteBrowser returns a WS URL and true when a WS URL is defined,
+// otherwise it returns an empty string and false. If more than one
+// WS URL was registered in newRemoteRegistry, a randomly chosen URL from
+// the list in a round-robin fashion is selected and returned.
+func (r *RemoteRegistry) IsRemoteBrowser() (string, bool) {
+	if !r.isRemoteBrowser {
+		return "", false
+	}
+
+	// Choose a random WS URL from the provided list
+	i, _ := rand.Int(rand.Reader, big.NewInt(int64(len(r.wsURLs))))
+	wsURL := r.wsURLs[i.Int64()]
+
+	return wsURL, true
+}

env/env_test.go → registry/remote_test.go

@@ -1,17 +1,19 @@
-package env
+package registry
 
 import (
 	"testing"
 
 	"github.com/stretchr/testify/require"
+
+	"github.com/grafana/xk6-browser/env"
 )
 
 func TestIsRemoteBrowser(t *testing.T) {
 	t.Parallel()
 
 	testCases := []struct {
 		name           string
-		envLookup      LookupFunc
+		envLookup      env.LookupFunc
 		expIsRemote    bool
 		expValidWSURLs []string
 	}{
@@ -70,7 +72,8 @@ func TestIsRemoteBrowser(t *testing.T) {
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
 
-			wsURL, isRemote := IsRemoteBrowser(tc.envLookup)
+			rr := NewRemoteRegistry(tc.envLookup)
+			wsURL, isRemote := rr.IsRemoteBrowser()
 
 			require.Equal(t, tc.expIsRemote, isRemote)
 			if isRemote {

tests/webvital_test.go

@@ -20,16 +20,16 @@ func TestWebVitalMetric(t *testing.T) {
 		browser  = newTestBrowser(t, withFileServer(), withSamplesListener(samples))
 		page     = browser.NewPage(nil)
 		expected = map[string]bool{
-			"webvital_time_to_first_byte":           false,
-			"webvital_time_to_first_byte_good":      false,
-			"webvital_first_contentful_paint":       false,
-			"webvital_first_contentful_paint_good":  false,
-			"webvital_largest_content_paint":        false,
-			"webvital_largest_content_paint_good":   false,
-			"webvital_first_input_delay":            false,
-			"webvital_first_input_delay_good":       false,
-			"webvital_cumulative_layout_shift":      false,
-			"webvital_cumulative_layout_shift_good": false,
+			"browser_web_vital_ttfb":      false,
+			"browser_web_vital_ttfb_good": false,
+			"browser_web_vital_fcp":       false,
+			"browser_web_vital_fcp_good":  false,
+			"browser_web_vital_lcp":       false,
+			"browser_web_vital_lcp_good":  false,
+			"browser_web_vital_fid":       false,
+			"browser_web_vital_fid_good":  false,
+			"browser_web_vital_cls":       false,
+			"browser_web_vital_cls_good":  false,
 		}
 	)