Add eventlet support and gunicorn config vals

[raymondjacobson]

Trello Card Link

https://trello.com/c/FJa1ydwW/1619-template-gunicorn-config

Description

Templates the gunicorn config for discovery provider with env vars.
Corresponding k8s change: https://github.com/AudiusProject/audius-k8s/pull/135

Services

• Discovery Provider

Does it touch a critical flow like Discovery indexing, Creator Node track upload, Creator Node gateway, or Creator Node file system?

Delete an option.

• ✅ Nope

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide repro instructions & any configuration.
Include log analysis if applicable.

1. Update local compose script to run prod-server instead of dev-server and ensured updating .env would change running gunicorn config
2. Pushed branch up as a hotfix & tested the same way on staging (deploying using both audius-k8s at master and audius-k8s at the branch)

With new audius-k8s

[2020-10-19 19:19:41 +0000] [1] [DEBUG] Current configuration:
  config: None
  bind: [':5000']
  backlog: 2048
  workers: 16
  worker_class: eventlet
  threads: 1
  worker_connections: 1000

with old audius-k8s

[2020-10-19 19:20:35 +0000] [1] [DEBUG] Current configuration:
  config: None
  bind: [':5000']
  backlog: 2048
  workers: 2
  worker_class: sync
  threads: 8
  worker_connections: 1000
  max_requests: 0
  max_requests_jitter: 0

[hareeshnagaraj]

is there an associated config update that is missing?

audius-protocol/discovery-provider/default_config.ini

Line 1 in 896eea4

[discprov]

i also think these should be audius_discprov_gunicorn_workers if we follow the format for other configs

[hareeshnagaraj]

oh because these are environment configs and not used by the service this doesn't really matter?

[raymondjacobson]

yeah -- the .ini is for python, this is before python's even running

[raymondjacobson]

config is all updated on the k8s side

[raymondjacobson]

there's a world in which we want this locally too, but we never run gunicorn locally as it stands, so it doesn't make a diff

[dmanjunath]

This looks good to me

[hareeshnagaraj]

looks good to me!