Add linter

[sozercan]

KBv2 update resolved some of the lint issues on scaffolding
This PR adds golangci-lint to makefile and CI and fixes some of the lint issues

Closes #230 and #165

[maxsmythe]

This is awesome!

[maxsmythe]

removing webhookname flag altogether is a breaking change, though there are other changes, so may be fine

[ritazh]

We should make the webhook name customizable and this should be the flag that allows users to provide that.

[sozercan]

@maxsmythe if we keep it, we'll have to add // nolint:varcheck,deadcode,unused to ignore linting

[maxsmythe]

@ritazh Webhook name (as in validation.gatekeeper.sh) is fully customizable via VWH config,

[ritazh]

but I dont think users can deploy VWH separately right?

[ritazh]

or did you mean they can modify this value in the deploy.yaml:

https://github.com/open-policy-agent/gatekeeper/blob/master/deploy/gatekeeper_kubebuilder_v2.yaml#L358

If so, then I guess we can just remove this flag.

[maxsmythe]

Ya, the next time we release, that kubebuilder_v2 yaml will be the order of the day. We should probably have a changeover plan.

[maxsmythe]

LGTM

[maxsmythe]

LGTM

[maxsmythe]

Just noticed that watchVitals became public, we should avoid leaking the internals of Watch Manager if we can

[maxsmythe]

This has the potential of double-counting GVKs, as more than one registrar could be listing a watch a single kind.

Part of the cleanup I was going to do was moving the registrar merge logic into the recordKeeper. I suggest:

func (r *recordKeeper) Get() map[schema.GroupVersionKind]vitals {
	r.intentMux.RLock()
	defer r.intentMux.RUnlock()
	cpy := make(map[string]map[schema.GroupVersionKind]vitals)
	for k := range r.intent {
		cpy[k] = make(map[schema.GroupVersionKind]vitals)
		for k2, v := range r.intent[k] {
			cpy[k][k2] = v
		}
	}
	managedKinds := make(map[schema.GroupVersionKind]vitals)
	for _, registrar := range cpy {
		for gvk, v := range registrar {
			if mk, ok := managedKinds[gvk]; ok {
				merged, err := mk.merge(v)
				if err != nil {
					return nil, nil, nil, err
				}
				managedKinds[gvk] = merged
			} else {
				managedKinds[gvk] = v
			}
		}
	}
        return managedKinds
}

Then GetGVK becomes:

func (r *recordKeeper) GetGVK() []schema.GroupVersionKind {
	var gvks []schema.GroupVersionKind
	for gvk := range r.Get() {
	   gvks = append(gvks, gvk)
       }
       return gvks

Note that a lock is not needed because the Get() function uses a read lock and returns a copy of the data, so this function is thread-safe without it.

[maxsmythe]

LGTM