nixpkgs/nixos/modules/services/backup/postgresql-backup.nix
pennae ef176dcf7e nixos/*: automatically convert option descriptions
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    nix-doc-munge --import nixos/**/*.nix

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2022-08-31 16:32:53 +02:00

182 lines
5.3 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.services.postgresqlBackup;
postgresqlBackupService = db: dumpCmd:
let
compressSuffixes = {
"none" = "";
"gzip" = ".gz";
"zstd" = ".zstd";
};
compressSuffix = getAttr cfg.compression compressSuffixes;
compressCmd = getAttr cfg.compression {
"none" = "cat";
"gzip" = "${pkgs.gzip}/bin/gzip -c -${toString cfg.compressionLevel}";
"zstd" = "${pkgs.zstd}/bin/zstd -c -${toString cfg.compressionLevel}";
};
mkSqlPath = prefix: suffix: "${cfg.location}/${db}${prefix}.sql${suffix}";
curFile = mkSqlPath "" compressSuffix;
prevFile = mkSqlPath ".prev" compressSuffix;
prevFiles = map (mkSqlPath ".prev") (attrValues compressSuffixes);
inProgressFile = mkSqlPath ".in-progress" compressSuffix;
in {
enable = true;
description = "Backup of ${db} database(s)";
requires = [ "postgresql.service" ];
path = [ pkgs.coreutils config.services.postgresql.package ];
script = ''
set -e -o pipefail
umask 0077 # ensure backup is only readable by postgres user
if [ -e ${curFile} ]; then
rm -f ${toString prevFiles}
mv ${curFile} ${prevFile}
fi
${dumpCmd} \
| ${compressCmd} \
> ${inProgressFile}
mv ${inProgressFile} ${curFile}
'';
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 = mkEnableOption (lib.mdDoc "PostgreSQL dumps");
startAt = mkOption {
default = "*-*-* 01:15:00";
type = with types; either (listOf str) str;
description = lib.mdDoc ''
This option defines (see `systemd.time` 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 = literalExpression "services.postgresqlBackup.databases == []";
type = lib.types.bool;
description = lib.mdDoc ''
Backup all databases using pg_dumpall.
This option is mutual exclusive to
`services.postgresqlBackup.databases`.
The resulting backup dump will have the name all.sql.gz.
This option is the default if no databases are specified.
'';
};
databases = mkOption {
default = [];
type = types.listOf types.str;
description = lib.mdDoc ''
List of database names to dump.
'';
};
location = mkOption {
default = "/var/backup/postgresql";
type = types.path;
description = lib.mdDoc ''
Path of directory where the PostgreSQL database dumps will be placed.
'';
};
pgdumpOptions = mkOption {
type = types.separatedString " ";
default = "-C";
description = lib.mdDoc ''
Command line options for pg_dump. This options is not used
if `config.services.postgresqlBackup.backupAll` is enabled.
Note that config.services.postgresqlBackup.backupAll is also active,
when no databases where specified.
'';
};
compression = mkOption {
type = types.enum ["none" "gzip" "zstd"];
default = "gzip";
description = lib.mdDoc ''
The type of compression to use on the generated database dump.
'';
};
compressionLevel = mkOption {
type = types.ints.between 1 19;
default = 6;
description = lib.mdDoc ''
The compression level used when compression is enabled.
gzip accepts levels 1 to 9. zstd accepts levels 1 to 19.
'';
};
};
};
config = mkMerge [
{
assertions = [
{
assertion = cfg.backupAll -> cfg.databases == [];
message = "config.services.postgresqlBackup.backupAll cannot be used together with config.services.postgresqlBackup.databases";
}
{
assertion = cfg.compression == "none" ||
(cfg.compression == "gzip" && cfg.compressionLevel >= 1 && cfg.compressionLevel <= 9) ||
(cfg.compression == "zstd" && cfg.compressionLevel >= 1 && cfg.compressionLevel <= 19);
message = "config.services.postgresqlBackup.compressionLevel must be set between 1 and 9 for gzip and 1 and 19 for zstd";
}
];
}
(mkIf cfg.enable {
systemd.tmpfiles.rules = [
"d '${cfg.location}' 0700 postgres - - -"
];
})
(mkIf (cfg.enable && cfg.backupAll) {
systemd.services.postgresqlBackup =
postgresqlBackupService "all" "pg_dumpall";
})
(mkIf (cfg.enable && !cfg.backupAll) {
systemd.services = listToAttrs (map (db:
let
cmd = "pg_dump ${cfg.pgdumpOptions} ${db}";
in {
name = "postgresqlBackup-${db}";
value = postgresqlBackupService db cmd;
}) cfg.databases);
})
];
}