How to configure psql wrapper in NixOS module

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1

Hi, I’m having some trouble making my psql behave nicely in NixOS. Since NixOS’s psql is wrapped, it doesn’t read my $EDITOR and I’m having to use nano to edit my SQL commands :frowning::frowning::frowning:. I’d like to configure the wrapper, or set a psqlrc.

Having read PostgreSQL - NixOS Wiki, I understand that I can use services.postgresql.settings to configure the PostgreSQL server settings, but I couldn’t find mention on how to configure the psql client. I didn’t figure out configuration options from reading the source either.

What do you think? Thanks.

2

If there is no way to configure it, maybe add a shellscriptBin or add an alias to your shell, which simply does EDITOR=... wrapped-psql?

3

Since it’s a wrapped psql, it simply ignores the environment. I would be happy to just use the EDITOR from my environment, but it gets ignored.

4

What makes you say that psql on NixOS is wrapped? It doesn’t seem to be to me: psql is a binary rather than a script on my system. In my testing, it also seemed to respect the EDITOR variable.

5

I checked that the environment is ignored like this:

TEST=test sudo -u postgres psql <db-name>

# \getenv a TEST                                                                                                                                                                                  
# \echo :a                                                                                                                                                                                        
:a

Conversely, if I use getenv to see the PATH, it gives me my Nix profiles apparently.

# \getenv a PATH                                                                                                                                                                                  
# \echo :a                                                                                                                                                                                        
/nix/store/<my-stuff>/bin:/run/wrappers/bin:/home/<user>/.nix-profile/bin:/etc/profiles/per-user/<user>/bin:/nix/var/nix/profiles/default/bin:/run/current-system/sw/bin
6

Indeed it seems that wrapping is not the issue. file /nix/store/cf5rrb1l9hmhys7346ghi13qd97p34xf-postgresql-15.3/bin/psql tells us the binary is an ELF.

7

The issue here is probably sudo, not psql. sudo generally only keeps around environment variables it’s configured to. And indeed, if I compare the output of env | sort and sudo env | sort, the latter is missing my EDITOR among many other things.

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