Installing postgresql-client

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1

Hi all,

I’m wondering how to install the psql command on NixOS. To be clear: I’m only interested in the client, not the server.

I’ve looked at the derivation but couldn’t find any pointers.

Is there a way to create a derivation without building from source?

Thanks!

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2

It seems that there is no split in the derivation.
You can just add the postgresql derivation to environment.systemPackages (or wherever you need it) and the psql command should be available.

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$ nix-shell -p postgresql --command 'psql --version'
psql (PostgreSQL) 9.6.10
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4

bump - did anybody solve this?

5

Does what @Mic92 mentions not work for you?

6

No as that postgresql package appears to install the server (alongside the client), which I am trying to avoid :slight_smile:

7

It pulls the binary into path, it doesn’t run it though or configure it.

If you are just annoyed by the binary being visible in your PATH a simple wrapper might solve that:

runCommandNoCC "psql" {} ''
  mkdir -p $out/bin
  ln -s ${postgresql}/bin/psql $out/bin/psql
''
8

I’m sorry, but I completely fail to see the issue here. Is your concern the fact that the server binaries are present in the path?

9

When I install postgresql into environment.systemPackages it also starts a postgres server daemon that I don’t want installer nor running since I use containers.

I’d rather just install the postgres-client so that I can connect to my containers etc.

I was hoping that since a couple of years had passed that potentially there was a solution already :smiley:

Nobbz’s looks like the best but was hoping for something as simple as just adding a package like postgresql-client

10

actually forget that i don’t think it installs it as a daemon!

11

Correct. Whenever you install anything via environment.systemPackages there is no possible way for a daemon to start. This will never happen and is useful for you to know. Often times people new to NixOS wonder why a service isn’t running after they installed it via environment.systemPackages, not realizing they need to “install” it via services.FOO.enable = true;.

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12

The only downside to not having the client and server split is the space used but as postgresql_14 currently takes up around 25mb, that’s really not an issue at all which is why nobody has put in the effort to split the 2.

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13

Apologies for the necropoast … but how about the use case where I’m using Nix to build a Docker image and I want to include psql (client) but not the postgres server?

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14

but how about the use case where I’m using Nix to build a Docker image and I want to include psql (client) but not the postgres server?

I’d like to do the same thing. Currently the runtime closure postgresql package is over 300MB, while I can find an pure psql image on docker hub under 10MB

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15

[…] how about the use case where I’m using Nix to build a Docker image and I want to include psql (client) but not the postgres server?

[…] I can find an pure psql image on docker hub under 10MB

Here’s one: https://hub.docker.com/r/jbergknoff/postgresql-client

We can get that image directly in Nix using dockerTools.pullImage:

pkgs.dockerTools.pullImage {
  # variables to update base image found using:
  #   xdg-open https://hub.docker.com/r/jbergknoff/postgresql-client/tags
  #   nix-shell -p nix-prefetch-docker
  #   nix-prefetch-docker --quiet --image-name jbergknoff/postgresql-client --image-tag latest --image-digest sha256:45e175ebb700cfd46e23a610477c3576550055ef40c394e663623946a5eced39
  imageName = "jbergknoff/postgresql-client";
  imageDigest = "sha256:45e175ebb700cfd46e23a610477c3576550055ef40c394e663623946a5eced39";
  finalImageName = "postgresql-client";
  finalImageTag = "latest";
  sha256 = "0vxmbsi725yxa1i8ysl3scbsnf6shqvhf104i3phwnkkqp6sfk68";
  os = "linux";
  arch = "amd64";
};

And it’s extensible!! You can use dockerTools.streamLayeredImage (or some equivalent) to layer images on top of each-other using the baseImage argument.

So in this case:

{
  pkgs ? import <nixpkgs> {},
  name ? "psql-client",
  version ? "0.0.0",
  # TODO supply some derivation that uses `psql` in ./script.nix
  server ? pkgs.callPackage ./script.nix { inherit pkgs; }
}: let
  baseImage = pkgs.dockerTools.pullImage {
    # variables to update base image found using:
    #   xdg-open https://hub.docker.com/r/jbergknoff/postgresql-client/tags
    #   nix-shell -p nix-prefetch-docker
    #   nix-prefetch-docker --quiet --image-name jbergknoff/postgresql-client --image-tag latest --image-digest sha256:45e175ebb700cfd46e23a610477c3576550055ef40c394e663623946a5eced39
    imageName = "jbergknoff/postgresql-client";
    imageDigest = "sha256:45e175ebb700cfd46e23a610477c3576550055ef40c394e663623946a5eced39";
    finalImageName = "postgresql-client";
    finalImageTag = "latest";
    sha256 = "0vxmbsi725yxa1i8ysl3scbsnf6shqvhf104i3phwnkkqp6sfk68";
    os = "linux";
    arch = "amd64";
  };
in pkgs.dockerTools.streamLayeredImage {
  name = "${name}-script-image";
  tag = version;
  inherit tag;
  fromImage = baseImage;
  contents = [ script ];
  config = {
    # your script can call psql
    Cmd = [ "${pkgs.lib.getExe script}" ];
    ExposedPorts = {
      "5432/tcp" = {};
    };
  };
}

See documentation at pkgs.dockerTools | nixpkgs

See more examples at nixpkgs/pkgs/build-support/docker/examples.nix at 21e9e52183fd52452c26a1d7957b0299a37fa83a · NixOS/nixpkgs · GitHub

Note that it may be better to make the Docker image yourself, as that above image with 10M downloads (at the time of writing) was last updated 4 years ago. Here is a Dockerfile example of how to achieve it on StackOverflow: postgresql - Postgres lean Docker image containing only "psql" client - Stack Overflow