feat: make plugin refresh interval configurable

[edaniszewski]

This PR:

• makes the interval for the plugin refresh task configurable

fixes #358

[MatthewHink]

Okay the refresh_every

As the configuration becomes more difficult we should doc (comment) this in the deploy files.

So many knobs, levers, tweaks can become unwieldy. Usually the less the better.

[MatthewHink]

I am strongly against this because it feels like it's masking the real bug.

The i2c plugins came up inactive on a deploy today, though normally they come up just fine.

Why does this help? - And thanks for merging.

-1.

[edaniszewski]

I saw the approve but the page didn't refresh so I didn't see the comment you left - my bad.

While I agree that having excessive amounts of configuration can be overwhelming and can then make an application feel fragile as it becomes an exercise in tinkering with configs, I do feel like some values need to be configurable for an application to be generally usable. It may be premature to add this now since we are currently the only ones using it, but if there ever are other users, their use case may be different from ours.

I opened an issue in the synse-docs repo to capture this change, so the configuration fields and values will be documented with examples, so even though it increases config complexity, it is navigable with docs.

As for this masking an issue of plugins coming up inactive - I don't think it does that. It just makes a value configurable. We could abuse this value to mask the issue, but we could also leverage it to adjust runtime conditions to try to replicate the actual issue and resolve it.