clarify that the url is a web socket

[claireolmstead]

Problem

The names of the env vales are confusing.

Link to GitHub Issue(s): #567

Solution

Clarify that one is a websocket.

Steps to Verify:

1. Run it and make sure it still works
2. No more instances of "FREQUENCY_URL"

[aramikm]

Looks good a few minor comments.

[aramikm]

nit: We already have SIWF_URL. Is this redundant or they are used differently?

[mattheworris]

They are different.

[claireolmstead]

Do we need to also change SIWF_URL to be SIWF_UI_URL? @mattheworris @aramikm

[mattheworris]

I do like SIWF_UI_URL but I'm fine with leaving SIWF_URL too, as you prefer.

[mattheworris]

• Paired with @claireolmstead on some changes
• Read through finalized changes
• Non-blocking comments
  🚢 it!

[JoeCap08055]

Sorry; just getting around to looking at this--last 2 weeks with hurricane & off-site have me in catch-up mode.
A couple of points:

• We've changed the name of the env var to include _WS_, but the config validation still allows http protocol
• Technically, there's no reason you couldn't specify an HTTP RPC endpoint; WebSocket is only required if you're doing subscriptions, which we avoid.

We should either disallow http protocol in the config, or eliminate specifying WebSocket/WS in the docs & env name.

I'd be okay with disallowing http, since it's less efficient (needs to establish a connection with each request); however, we might want to consider that some client might have network constraints in their environment that preclude using WebSocket.