tvl-depot/ops/modules/automatic-gc.nix
Vincent Ambo aa122cbae7 style: format entire depot with nixpkgs-fmt
This CL can be used to compare the style of nixpkgs-fmt against other
formatters (nixpkgs, alejandra).

Change-Id: I87c6abff6bcb546b02ead15ad0405f81e01b6d9e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/4397
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Reviewed-by: lukegb <lukegb@tvl.fyi>
Reviewed-by: wpcarro <wpcarro@gmail.com>
Reviewed-by: Profpatsch <mail@profpatsch.de>
Reviewed-by: kanepyork <rikingcoding@gmail.com>
Reviewed-by: tazjin <tazjin@tvl.su>
Reviewed-by: cynthia <cynthia@tvl.fyi>
Reviewed-by: edef <edef@edef.eu>
Reviewed-by: eta <tvl@eta.st>
Reviewed-by: grfn <grfn@gws.fyi>
2022-01-31 16:11:53 +00:00

92 lines
2.6 KiB
Nix

# Defines a service for automatically collecting Nix garbage
# periodically, without relying on the (ostensibly broken) Nix options
# for min/max space available.
{ config, lib, pkgs, ... }:
let
cfg = config.services.depot.automatic-gc;
description = "Automatically collect Nix garbage";
GiBtoKiB = n: n * 1024 * 1024;
GiBtoBytes = n: n * 1024 * 1024 * 1024;
gcScript = pkgs.writeShellScript "automatic-nix-gc" ''
set -ueo pipefail
readonly MIN_THRESHOLD_KIB="${toString (GiBtoKiB cfg.diskThreshold)}"
readonly MAX_FREED_BYTES="${toString (GiBtoBytes cfg.maxFreed)}"
readonly GEN_THRESHOLD="${cfg.preserveGenerations}"
readonly AVAILABLE_KIB=$(df --sync /nix --output=avail | tail -n1)
if [ "''${AVAILABLE_KIB}" -lt "''${MIN_THRESHOLD_KIB}" ]; then
echo "Have ''${AVAILABLE_KIB} KiB, but want ''${MIN_THRESHOLD_KIB} KiB."
echo "Triggering Nix garbage collection up to ''${MAX_FREED_BYTES} bytes."
set -x
${config.nix.package}/bin/nix-collect-garbage \
--delete-older-than "''${GEN_THRESHOLD}" \
--max-freed "''${MAX_FREED_BYTES}"
else
echo "Skipping GC, enough space available"
fi
'';
in
{
options.services.depot.automatic-gc = {
enable = lib.mkEnableOption description;
interval = lib.mkOption {
type = lib.types.str;
example = "1h";
description = ''
Interval between garbage collection runs, specified in
systemd.time(7) format.
'';
};
diskThreshold = lib.mkOption {
type = lib.types.int;
example = "100";
description = ''
Minimum amount of space that needs to be available (in GiB) on
the partition holding /nix. Garbage collection is triggered if
it falls below this.
'';
};
maxFreed = lib.mkOption {
type = lib.types.int;
example = "420";
description = ''
Maximum amount of space to free in a single GC run, in GiB.
'';
};
preserveGenerations = lib.mkOption {
type = lib.types.str;
default = "90d";
description = ''
Preserve NixOS generations younger than the specified value,
in the format expected by nix-collect-garbage(1).
'';
};
};
config = lib.mkIf cfg.enable {
systemd.services.automatic-gc = {
inherit description;
script = "${gcScript}";
serviceConfig.Type = "oneshot";
};
systemd.timers.automatic-gc = {
inherit description;
requisite = [ "nix-daemon.service" ];
wantedBy = [ "multi-user.target" ];
timerConfig = {
OnActiveSec = "1";
OnUnitActiveSec = cfg.interval;
};
};
};
}