nixpkgs/nixos/modules/services/monitoring
Maximilian Bosch 48459567ae nixos/postgresql: drop ensurePermissions, fix ensureUsers for postgresql15
Closes #216989

First of all, a bit of context: in PostgreSQL, newly created users don't
have the CREATE privilege on the public schema of a database even with
`ALL PRIVILEGES` granted via `ensurePermissions` which is how most of
the DB users are currently set up "declaratively"[1]. This means e.g. a
freshly deployed Nextcloud service will break early because Nextcloud
itself cannot CREATE any tables in the public schema anymore.

The other issue here is that `ensurePermissions` is a mere hack. It's
effectively a mixture of SQL code (e.g. `DATABASE foo` is relying on how
a value is substituted in a query. You'd have to parse a subset of SQL
to actually know which object are permissions granted to for a user).

After analyzing the existing modules I realized that in every case with
a single exception[2] the UNIX system user is equal to the db user is
equal to the db name and I don't see a compelling reason why people
would change that in 99% of the cases. In fact, some modules would even
break if you'd change that because the declarations of the system user &
the db user are mixed up[3].

So I decided to go with something new which restricts the ways to use
`ensure*` options rather than expanding those[4]. Effectively this means
that

* The DB user _must_ be equal to the DB name.
* Permissions are granted via `ensureDBOwnerhip` for an attribute-set in
  `ensureUsers`. That way, the user is actually the owner and can
  perform `CREATE`.
* For such a postgres user, a database must be declared in
  `ensureDatabases`.

For anything else, a custom state management should be implemented. This
can either be `initialScript`, doing it manual, outside of the module or
by implementing proper state management for postgresql[5], but the
current state of `ensure*` isn't even declarative, but a convergent tool
which is what Nix actually claims to _not_ do.

Regarding existing setups: there are effectively two options:

* Leave everything as-is (assuming that system user == db user == db
  name): then the DB user will automatically become the DB owner and
  everything else stays the same.

* Drop the `createDatabase = true;` declarations: nothing will change
  because a removal of `ensure*` statements is ignored, so it doesn't
  matter at all whether this option is kept after the first deploy (and
  later on you'd usually restore from backups anyways).

  The DB user isn't the owner of the DB then, but for an existing setup
  this is irrelevant because CREATE on the public schema isn't revoked
  from existing users (only not granted for new users).

[1] not really declarative though because removals of these statements
    are simply ignored for instance: https://github.com/NixOS/nixpkgs/issues/206467
[2] `services.invidious`: I removed the `ensure*` part temporarily
    because it IMHO falls into the category "manage the state on your
    own" (see the commit message). See also
    https://github.com/NixOS/nixpkgs/pull/265857
[3] e.g. roundcube had `"DATABASE ${cfg.database.username}" = "ALL PRIVILEGES";`
[4] As opposed to other changes that are considered a potential fix, but
    also add more things like collation for DBs or passwords that are
    _never_ touched again when changing those.
[5] As suggested in e.g. https://github.com/NixOS/nixpkgs/issues/206467
2023-11-13 17:16:25 +01:00
..
prometheus kea: use separate runtime directories for each service 2023-10-26 02:51:43 +07:00
alerta.nix
apcupsd.nix
arbtt.nix
below.nix nixos/below: Document maintainer 2023-09-13 10:25:28 +00:00
bosun.nix treewide: fix redirected and broken URLs 2023-11-11 10:49:01 +01:00
cadvisor.nix
certspotter.md nixos/certspotter: init 2023-10-28 14:19:36 +07:00
certspotter.nix nixos/certspotter: init 2023-10-28 14:19:36 +07:00
cockpit.nix
collectd.nix
das_watchdog.nix
datadog-agent.nix fix whitespace issue 2023-07-18 00:20:46 -04:00
do-agent.nix
fusion-inventory.nix
goss.md nixos/goss: init 2023-10-27 08:00:48 +02:00
goss.nix nixos/goss: init 2023-10-27 08:00:48 +02:00
grafana-agent.nix
grafana-image-renderer.nix nixos/grafana-image-renderer: use Grafana's http_addr rather than localhost 2023-10-26 12:57:39 +02:00
grafana-reporter.nix
grafana.nix treewide: fix redirected and broken URLs 2023-11-11 10:49:01 +01:00
graphite.nix treewide: fix redirected and broken URLs 2023-11-11 10:49:01 +01:00
hdaps.nix
heapster.nix
incron.nix
kapacitor.nix
karma.nix
kthxbye.nix
librenms.nix nixos/librenms: init 2023-10-16 13:28:22 +02:00
loki.nix
longview.nix
mackerel-agent.nix nixos: fix bad mkEnableOption descriptions 2023-10-20 16:22:40 +01:00
metricbeat.nix
mimir.nix nixos/mimir: add extraFlags option 2023-09-04 20:26:02 +00:00
monit.nix
munin.nix treewide: fix redirected and broken URLs 2023-11-11 10:49:01 +01:00
nagios.nix treewide: fix redirected and broken URLs 2023-11-11 10:49:01 +01:00
netdata.nix nixos/services/netdata: add systemd-journald plugin as a privileged wrapper 2023-11-01 00:16:30 +01:00
opentelemetry-collector.nix
osquery.nix nixos/osquery: do not use the local database for osqueryi 2023-07-26 17:22:22 +02:00
parsedmarc.md
parsedmarc.nix
riemann-dash.nix
riemann-tools.nix
riemann.nix
scollector.nix
smartd.nix nixos/smartd: Fix mail recipient field 2023-08-05 20:01:42 +01:00
statsd.nix
sysstat.nix
teamviewer.nix
telegraf.nix
thanos.nix
tremor-rs.nix
tuptime.nix
unpoller.nix
ups.nix nixos/ups: replace activationScript via tmpfiles 2023-10-25 23:44:01 +02:00
uptime-kuma.nix
uptime.nix
vmagent.nix nixos/vmagent: add extraOptions option 2023-08-24 15:09:29 +02:00
vmalert.nix nixos/vmalert: init 2023-05-30 07:41:00 -04:00
vnstat.nix
zabbix-agent.nix
zabbix-proxy.nix nixos/postgresql: drop ensurePermissions, fix ensureUsers for postgresql15 2023-11-13 17:16:25 +01:00
zabbix-server.nix nixos/postgresql: drop ensurePermissions, fix ensureUsers for postgresql15 2023-11-13 17:16:25 +01:00