nixpkgs/nixos/modules/services
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
..
admin
amqp
audio treewide: fix redirected and broken URLs 2023-11-11 10:49:01 +01:00
backup nixos/restic: allow timer to be disabled 2023-11-07 22:37:37 +01:00
blockchain/ethereum erigon: add package option to override default version 2023-10-29 18:27:13 +00:00
cluster hadoop, nixos/hadoop: remove untarDir 2023-09-22 16:34:07 +05:30
computing treewide: fix redirected and broken URLs 2023-11-11 10:49:01 +01:00
continuous-integration nixos/woodpecker-server: fix environmentFile example 2023-11-02 18:14:46 +01:00
databases nixos/postgresql: drop ensurePermissions, fix ensureUsers for postgresql15 2023-11-13 17:16:25 +01:00
desktops nixos/gnome/at-spi2-core: fix disabling a11y in all contexts 2023-11-06 12:40:38 -05:00
development nixos/postgresql: drop ensurePermissions, fix ensureUsers for postgresql15 2023-11-13 17:16:25 +01:00
display-managers nixos/greetd: autostart GNOME Keyring when enabled 2023-11-05 12:22:52 +01:00
editors emacs: remove outdated doc about package initialization 2023-08-25 10:22:30 +00:00
finance nixos/postgresql: drop ensurePermissions, fix ensureUsers for postgresql15 2023-11-13 17:16:25 +01:00
games nixos/asf: update hardening options to match upstream 2023-10-21 13:50:05 +02:00
hardware treewide: fix redirected and broken URLs 2023-11-11 10:49:01 +01:00
home-automation nixos/home-assistant: add customComponents support 2023-11-10 22:00:36 +01:00
logging treewide: fix redirected and broken URLs 2023-11-11 10:49:01 +01:00
mail nixos/postgresql: drop ensurePermissions, fix ensureUsers for postgresql15 2023-11-13 17:16:25 +01:00
matrix nixos/postgresql: drop ensurePermissions, fix ensureUsers for postgresql15 2023-11-13 17:16:25 +01:00
misc nixos/postgresql: drop ensurePermissions, fix ensureUsers for postgresql15 2023-11-13 17:16:25 +01:00
monitoring nixos/postgresql: drop ensurePermissions, fix ensureUsers for postgresql15 2023-11-13 17:16:25 +01:00
network-filesystems treewide: fix redirected and broken URLs 2023-11-11 10:49:01 +01:00
networking nixos/nix-serve: also set extra-allowed-users 2023-11-12 14:09:31 +01:00
printing nixos/printing: Fix openFirewall option 2023-11-07 10:21:48 +01:00
scheduling treewide: use optionalString instead of 'then ""' 2023-06-24 20:19:19 +02:00
search nixos/typesense: disable MemoryDenyWriteExecute which is needed since 0.25.1 2023-09-23 16:37:23 +02:00
security nixos/postgresql: drop ensurePermissions, fix ensureUsers for postgresql15 2023-11-13 17:16:25 +01:00
system Merge pull request #263203 from nikstur/replace-activation 2023-10-28 10:17:15 +02:00
torrent treewide: fix redirected and broken URLs 2023-11-11 10:49:01 +01:00
tracing nixos/tempo: add extraFlags option 2023-08-14 18:07:24 +02:00
ttys treewide: rename fonts.fonts to fonts.packages 2023-07-24 17:34:39 +02:00
video treewide: fix redirected and broken URLs 2023-11-11 10:49:01 +01:00
wayland nixos/cage: add environment config 2023-05-28 23:36:22 +02:00
web-apps nixos/postgresql: drop ensurePermissions, fix ensureUsers for postgresql15 2023-11-13 17:16:25 +01:00
web-servers nixos/postgresql: drop ensurePermissions, fix ensureUsers for postgresql15 2023-11-13 17:16:25 +01:00
x11 treewide: fix redirected and broken URLs 2023-11-11 10:49:01 +01:00