Query flooding if reverse proxy is down

[Ultimator14]

I'm using a docker image of synapse (matrix.mydomain) and dimension (dimension.mydomain) behind a reverse proxy which handles encryption. From time to time, the reverse proxy crashes. Dimension is therefore unable to access matrix.mydomain.

Then dimension:

1. Queries the DNS for matrix.mydomain
2. Tries to connect to matrix.mydomain
3. Gets ECONNREFUSED
4. Immediately starts from 1 again

Last time the proxy was down for 5min. Meanwhile dimension sent 70.000 DNS queries which is more than 200 queries per second.
The CPU usage also goes up to 100%. This looks like an infinite loop to me.
It would be good to add a delay before retrying the failed connection.

The logs show this message for every connection attempt:

Mon, 14 Mar 2022 12:44:30 GMT [DEBUG] [MatrixClientLite] Performing sync with token <mytoken>
Mon, 14 Mar 2022 12:44:30 GMT [DEBUG] [MatrixHttpClient (REQ-<ascending number>)] GET https://matrix.pygos.space/_matrix/client/r0/sync
Mon, 14 Mar 2022 12:44:30 GMT [ERROR] [MatrixHttpClient (REQ-<ascending number>)] Error: connect ECONNREFUSED <myip>:443
    at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1148:16) {
  errno: -111,
  code: 'ECONNREFUSED',
  syscall: 'connect',
  address: '<myip>',
  port: 443
}
Mon, 14 Mar 2022 12:44:30 GMT [ERROR] [MatrixClientLite] Error: connect ECONNREFUSED <myip>:443
    at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1148:16) {
  errno: -111,
  code: 'ECONNREFUSED',
  syscall: 'connect',
  address: '<myip>',
  port: 443
}

[Ultimator14]

Looks like this is an issue in matrix-bot-sdk which has been solved already in release v0.6.0-beta.1 by this Pull Request. However dimension still requires v0.5.19. I guess a version bump would be sufficient.