Add performance testing workflow

[rzats]

Prerequisites:

• Unless it is a documentation hotfix it should be merged against the dev branch
• Branch is up-to-date with the branch to be merged with, i.e. dev
• Build is successful
• Code is cleaned up and formatted

Summary

Implements an automatable system for on-demand stability tests based on the scalability-testing-rig PRD.

This first version of the testing rig launches a GitHub Actions runner off of a pull request based on a set comment (/run performance test) and, in order-

• sets up WireGuard in order to access the staging Delphi database
• clones the delphi-epidata repo, switching it to the pull request's branch
• sets up an environment with various other repos similar to the install.sh script
• builds and runs an instance of the epidata web server + API
• runs Locust, a performance testing toolkit, targeting the local API we just created with a runtime of 15 minutes and 10 users spawning at a rate of 1 per second:

--users 10 --spawn-rate 1 --headless -t 15m

• links to Locust's report (which is contained in stdout) by creating a comment on the original pull request.

IMPORTANT: a prerequisite for this to function is for several secrets to be added to the repository.

These are as follows - various WireGuard credentials needed to set up the connection:

WG_PERF_ENDPOINT
WG_PERF_ENDPOINT_PUBLIC_KEY
WG_PERF_IPS
WG_PERF_ALLOWED_IPS
WG_PERF_PRIVATE_KEY

and the staging database connection string, including username & password:

DB_CONN_STRING

[melange396]

looks pretty cool! i had a couple little doc/naming things, but im mostly concerned with how much you might be able to take out of the repo cloning section. v4.py is a straight copy out of the admin repository, correct?

[rzats]

@melange396 applied the fixes!

v4.py and the sample of queries are both a copy from the private repo, yeah. We can also upload the larger query sample file to S3 or similar, and then download it in the GitHub Action; or git clone the private admin repo although this may run into issues with token permissions.

[melange396]

looks good!