When enabling the account validity feature, Synapse will look at startup for registered account without an expiration date, and will set one equals to 'now + validity_period' for them. On large servers, it can mean that a large number of users will have the same expiration date, which means that they will all be sent a renewal email at the same time, which isn't ideal.
In order to mitigate this, this PR allows server admins to define a 'max_delta' so that the expiration date is a random value in the [now + validity_period ; now + validity_period + max_delta] range. This allows renewal emails to be progressively sent over a configured period instead of being sent all in one big batch.
If account validity is enabled in the server's configuration, this job will run at startup as a background job and will stick an expiration date to any registered account missing one.
* Rate-limiting for registration
* Add unit test for registration rate limiting
* Add config parameters for rate limiting on auth endpoints
* Doc
* Fix doc of rate limiting function
Co-Authored-By: babolivier <contact@brendanabolivier.com>
* Incorporate review
* Fix config parsing
* Fix linting errors
* Set default config for auth rate limiting
* Fix tests
* Add changelog
* Advance reactor instead of mocked clock
* Move parameters to registration specific config and give them more sensible default values
* Remove unused config options
* Don't mock the rate limiter un MAU tests
* Rename _register_with_store into register_with_store
* Make CI happy
* Remove unused import
* Update sample config
* Fix ratelimiting test for py2
* Add non-guest test
Since we're not doing refresh tokens any more, we should start killing off the
dead code paths. /tokenrefresh itself is a bit of a thornier subject, since
there might be apps out there using it, but we can at least not generate
refresh tokens on new logins.
