nixpkgs/nixos/modules/services/backup/postgresql-backup.nix

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{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.services.postgresqlBackup;
postgresqlBackupService = db: dumpCmd:
{
enable = true;
description = "Backup of ${db} database(s)";
requires = [ "postgresql.service" ];
script = ''
umask 0077 # ensure backup is only readable by postgres user
if [ -e ${cfg.location}/${db}.sql.gz ]; then
${pkgs.coreutils}/bin/mv ${cfg.location}/${db}.sql.gz ${cfg.location}/${db}.prev.sql.gz
fi
${dumpCmd} | \
${pkgs.gzip}/bin/gzip -c > ${cfg.location}/${db}.sql.gz
'';
serviceConfig = {
Type = "oneshot";
User = "postgres";
};
startAt = cfg.startAt;
};
in {
imports = [
(mkRemovedOptionModule [ "services" "postgresqlBackup" "period" ] ''
A systemd timer is now used instead of cron.
The starting time can be configured via <literal>services.postgresqlBackup.startAt</literal>.
'')
];
options = {
services.postgresqlBackup = {
enable = mkOption {
default = false;
description = ''
Whether to enable PostgreSQL dumps.
'';
};
startAt = mkOption {
default = "*-*-* 01:15:00";
description = ''
This option defines (see <literal>systemd.time</literal> for format) when the
databases should be dumped.
The default is to update at 01:15 (at night) every day.
'';
};
backupAll = mkOption {
default = cfg.databases == [];
defaultText = "services.postgresqlBackup.databases == []";
type = lib.types.bool;
description = ''
Backup all databases using pg_dumpall.
This option is mutual exclusive to
<literal>services.postgresqlBackup.databases</literal>.
The resulting backup dump will have the name all.sql.gz.
This option is the default if no databases are specified.
'';
};
databases = mkOption {
default = [];
description = ''
List of database names to dump.
'';
};
location = mkOption {
default = "/var/backup/postgresql";
description = ''
Location to put the gzipped PostgreSQL database dumps.
'';
};
pgdumpOptions = mkOption {
type = types.separatedString " ";
default = "-C";
description = ''
Command line options for pg_dump. This options is not used
if <literal>config.services.postgresqlBackup.backupAll</literal> is enabled.
Note that config.services.postgresqlBackup.backupAll is also active,
when no databases where specified.
'';
};
};
};
config = mkMerge [
{
assertions = [{
assertion = cfg.backupAll -> cfg.databases == [];
message = "config.services.postgresqlBackup.backupAll cannot be used together with config.services.postgresqlBackup.databases";
}];
}
(mkIf cfg.enable {
systemd.tmpfiles.rules = [
"d '${cfg.location}' 0700 postgres - - -"
];
})
(mkIf (cfg.enable && cfg.backupAll) {
systemd.services.postgresqlBackup =
postgresqlBackupService "all" "${config.services.postgresql.package}/bin/pg_dumpall";
})
(mkIf (cfg.enable && !cfg.backupAll) {
systemd.services = listToAttrs (map (db:
let
cmd = "${config.services.postgresql.package}/bin/pg_dump ${cfg.pgdumpOptions} ${db}";
in {
name = "postgresqlBackup-${db}";
value = postgresqlBackupService db cmd;
}) cfg.databases);
})
];
}