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nixpkgs/nixos/modules/services/backup/postgresql-backup.nix
Jörg Thalheim 1af4f366ca
nixos/postgresqlBackup: add backupAll option
For large setups it is useful to list all databases explicit
(for example if temporary databases are also present) and store them in extra
files.
For smaller setups it is more convenient to just backup all databases at once,
because it is easy to forget to update configuration when adding/renaming
databases. pg_dumpall also has the advantage that it backups users/passwords.

As a result the module becomes easier to use because it is sufficient
in the default case to just set one option (services.postgresqlBackup.enable).
2019-01-19 11:41:06 +00:00

126 lines
3.3 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.services.postgresqlBackup;
postgresqlBackupService = db: dumpCmd:
{
enable = true;
description = "Backup of ${db} database(s)";
requires = [ "postgresql.service" ];
preStart = ''
mkdir -m 0700 -p ${cfg.location}
chown postgres ${cfg.location}
'';
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";
PermissionsStartOnly = "true";
User = "postgres";
};
startAt = cfg.startAt;
};
in {
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.string;
default = "-Cbo";
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 && 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);
})
];
}