external module names must be prefixed with '%s', tried to r

Error message

external module names must be prefixed with '%s', tried to register: %s

What it means

Error "external module names must be prefixed with '%s', tried to register: %s" thrown in grafana/k6.

Source

Thrown at js/modules/modules.go:23

	"context"
	"fmt"
	"strings"

	"github.com/grafana/sobek"

	"go.k6.io/k6/v2/ext"
	"go.k6.io/k6/v2/js/common"
	"go.k6.io/k6/v2/lib"
)

const extPrefix string = "k6/x/"

// Register the given mod as an external JavaScript module that can be imported
// by name. The name must be unique across all registered modules and must be
// prefixed with "k6/x/", otherwise this function will panic.
func Register(name string, mod any) {
	if !strings.HasPrefix(name, extPrefix) {
		panic(fmt.Errorf("external module names must be prefixed with '%s', tried to register: %s", extPrefix, name))
	}

	ext.Register(name, ext.JSExtension, mod)
}

// Module is the interface js modules should implement in order to get access to the VU
type Module interface {
	// NewModuleInstance will get modules.VU that should provide the module with a way to interact with the VU.
	// This method will be called for *each* VU that imports the module *once* per that VU.
	NewModuleInstance(VU) Instance
}

// Instance is what a module needs to return
type Instance interface {
	Exports() Exports
}

// VU gives access to the currently executing VU to a module Instance

View on GitHub (pinned to 93accf6570)

When it happens

Trigger: Thrown at js/modules/modules.go:23 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of grafana/k6@93accf6570 (2026-08-15). Data as JSON: /api/errors/3d0255dc30572409. Report an issue: GitHub.