Additional methods to a k6 modules API

[olegbespalov]

What?

During the code review of the k6#2365 there was a suggestion about the improvement readability/maintainability of the logic that is sensible to the execution state (initial context or not).

There are plenty of places where we check this like:

state := c.vu.State()
if state == nil {
	return false, errConnectInInitContext
}

This looks okay, but it can be better if we introduce the additional method that will be just about the checking if we in the initial context.

For example it can be something, like:

if modules.InInitContext(c.vu) {
	return false, errConnectInInitContext
}

or since it depends on the property of the VU

if c.vu.InInitContext() {
	return false, errConnectInInitContext
}

Probably the same applies to a checking init environment:

initEnv := c.vu.InitEnv()
if initEnv == nil {
    return nil, errors.New("missing init environment")
}

There are plenty of places where we do this thing:

grep --exclude-dir=vendor -ER "if state == nil" ./       
./k6/js/modules/k6/http/request.go:	if state == nil {
./k6/js/modules/k6/http/request.go:	if state == nil {
./k6/js/modules/k6/http/request.go:	if state == nil {
./k6/js/modules/k6/k6.go:	if state == nil {
./k6/js/modules/k6/k6.go:	if state == nil {
./k6/js/modules/k6/ws/ws.go:	if state == nil {
./k6/js/modules/k6/metrics/metrics.go:	if state == nil {
./k6/js/modules/k6/grpc/client.go:	if state == nil {
./k6/js/modules/k6/grpc/client.go:	if state == nil {

grep --exclude-dir=vendor -ER "if initEnv == nil" ./
./js/modules/k6/metrics/metrics.go:	if initEnv == nil {
./js/modules/k6/grpc/client.go:	if initEnv == nil {

Why?

• Having a dedicated method is more human-friendly since it explicitly names the case.
• If we consolidate such checks, it will be better for the long term since we also improve the maintainability of the code.

[olegbespalov]

I am closing this for now since there was no consensus inside the team on whether that's really needed.