✨ Allow user to define how create managed objects

[shawn-hurley]

• Allow the user to specify in the options how to create the client,
  cache, and how to construct the delegating client.

fixes #226

[DirectXMan12]

hmm... we try to avoid exposing a difference between these two at this level. What's the usecase for separating them? It's probably better/clearer to just have NewClient, which means NewDelegatingClient, and not leak the fact that we have a difference to the user/require the user to have that distinction.

[shawn-hurley]

The use case is that I want to not use the DelegatingReader for my client. I would like my client to use the cache for unstructured types.

Because there is no other way to override this client this is the only way that I can think of to update it. Thoughts?

[DirectXMan12]

but there's not really a use for NewClient except as a step in constructing the delegating client (unless I've missed something/am misremembering something), so we can just elide that and have:

type Options struct {
    ...
    NewClient func(...) client.Client
    ...
}

func defaultNewClient(...) client.Client {
    directClient := newClient(...)
    return &DelegatingClient{
        Writer: directClient,
        Reader: cacheClient,
    }
}

[shawn-hurley]

I was still thinking about them as two things but I think you are completely correct, I will update now!

[DirectXMan12]

missing godoc, otherwise looks awesome

[DirectXMan12]

This needs godoc

[shawn-hurley]

@DirectXMan12 I will take as a follow up to update the kubebuilder book around the manager. It looks like there is no section on the options to the manager, WDYT about a new section that describes the fields and examples on how to use them?

[shawn-hurley]

@DirectXMan12 LMK if there is anything else?

[DirectXMan12]

@shawn-hurley sounds fine to me.

/lgtm
/approve

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[DirectXMan12]

When we get our new general dep injection story solve, we may end up tweaking this slightly, but this seems to solve a real usecase right now, and isn't particularly onerous.

@pwittrock FYI