Backporting this security update to release-19.03 would require a more recent version of pythonPackages.service-identity (18.1.0 instead of 17.0.0 currently in 19.03).

I'm not sure whether we should update that package globally or use a different version locally for the backport.

Backport: #65464

@ofborg build nixosTests.matrix-synapse

@Ekleog The NixOS test seems to be broken on master when running on ofborg (matrix-synapse seems to complain about not being able to connect to postgres).
It passes locally on NixOS 19.03 though.

@pacien yup, already had that issue last time, with the verdict being that it's likely an issue of ofborg being too slow -- currently running locally, will merge as soon as it completes :)

It seems to work fine on the release-19.03 branch but fails consistently on master so it might not be a slowness issue.

I would guess it's an upgrade to postgresql that's slowed down startup, and so when running in a VM in a VM (@grahamc's guess last time I asked was it was due to an ofborg runner running inside a VM) it goes over the startup timeout.

Anyway, there is no regression compared to current master, and this looks like a postgresql issue, so I'm going to merge this for now and poke @ocharles @thoughtpolice @danbst in case they have some idea of why this might be happening with postgresql on ofborg and/or whether they saw similar things happening with the postgresql tests. :)