selfhostblocks/modules/blocks/sanoid.nix

164 lines
4.3 KiB
Nix

{
config,
lib,
pkgs,
shb,
utils,
...
}:
let
cfg = config.shb.sanoid;
restoreScriptName = name: "sanoid-${utils.escapeSystemdPath name}-restore";
backupScriptBase = "sanoid";
restoreScript =
name:
pkgs.writers.writePython3Bin (restoreScriptName name)
{
flakeIgnore = [ "E501" ];
}
''
import argparse
import subprocess
import sys
dataset = "${name}"
class ZFSError(Exception):
pass
def run_command(cmd: list[str]) -> str:
try:
result = subprocess.run(
cmd,
check=True,
text=True,
capture_output=True,
)
return result.stdout.strip()
except subprocess.CalledProcessError as e:
raise ZFSError(
f"Command failed: {' '.join(cmd)}\n"
f"Exit code: {e.returncode}\n"
f"stderr: {e.stderr.strip()}"
) from e
def list_snapshots() -> None:
"""List all ZFS snapshots."""
output = run_command(["zfs", "list", "-H", "-t", "snapshot", dataset])
if not output:
return []
return output.splitlines()
def restore_snapshot(snapshot: str) -> None:
"""Rollback to a given snapshot."""
if not snapshot:
raise ValueError("Snapshot name must not be empty")
print(f"Rolling back to snapshot: {snapshot}")
run_command(["zfs", "rollback", "-r", snapshot])
print("Rollback completed successfully.")
def build_parser() -> argparse.ArgumentParser:
parser = argparse.ArgumentParser(description=f"Restore script for {dataset}")
subparsers = parser.add_subparsers(dest="command", required=True)
subparsers.add_parser(
"snapshots",
help="List all ZFS snapshots",
)
restore_parser = subparsers.add_parser(
"restore",
help="Rollback to a specific snapshot",
)
restore_parser.add_argument(
"snapshot",
help="Snapshot name (e.g. pool/dataset@snapname)",
)
return parser
def main():
parser = build_parser()
args = parser.parse_args()
try:
if args.command == "snapshots":
snapshots = list_snapshots()
for s in snapshots:
print(s)
elif args.command == "restore":
restore_snapshot(args.snapshot)
else:
parser.print_help()
sys.exit(1)
except ZFSError as e:
print(f"ERROR: {e}", file=sys.stderr)
sys.exit(1)
except Exception as e:
print(f"Unexpected error: {e}", file=sys.stderr)
sys.exit(1)
if __name__ == "__main__":
main()
'';
in
{
imports = [
../../lib/module.nix
];
options.shb.sanoid.backup = lib.mkOption {
description = "Sanoid prodiver for file backup contract";
default = { };
type = lib.types.attrsOf (
lib.types.submodule (
{ name, ... }:
{
options = shb.contracts.backup.mkProvider {
resultCfg = {
restoreScript = restoreScriptName name;
restoreScriptText = restoreScriptName "<name>";
backupService = "${backupScriptBase}.service";
backupServiceText = "${backupScriptBase}.service";
};
settings = lib.mkOption {
description = "Options passed to the `services.sanoid.datasets.<name>` option.";
default = { };
type = lib.types.attrsOf lib.types.anything;
};
};
}
)
);
};
config = lib.mkIf (cfg.backup != { }) {
services.sanoid.enable = true;
services.sanoid.datasets =
let
mkDataset = name: cfg': {
inherit name;
value = cfg'.settings;
};
in
lib.mapAttrs' mkDataset cfg.backup;
environment.systemPackages = map restoreScript (lib.attrNames cfg.backup);
};
}