{ config, lib, pkgs, ... }: with import ; let out = { options.krebs.backup = api; config = lib.mkIf cfg.enable imp; }; cfg = config.krebs.backup; api = { enable = mkEnableOption "krebs.backup" // { default = true; }; plans = mkOption { default = {}; type = types.attrsOf (types.submodule ({ config, ... }: { options = { enable = mkEnableOption "krebs.backup.${config.name}" // { default = true; }; method = mkOption { type = types.enum ["pull" "push"]; }; name = mkOption { type = types.str; default = config._module.args.name; }; src = mkOption { type = types.krebs.file-location; }; dst = mkOption { type = types.krebs.file-location; }; startAt = mkOption { default = "hourly"; type = with types; nullOr str; # TODO systemd.time(7)'s calendar event }; snapshots = mkOption { default = { hourly = { format = "%Y-%m-%dT%H"; retain = 4; }; daily = { format = "%Y-%m-%d"; retain = 7; }; weekly = { format = "%YW%W"; retain = 4; }; monthly = { format = "%Y-%m"; retain = 12; }; yearly = { format = "%Y"; }; }; type = types.attrsOf (types.submodule { options = { format = mkOption { type = types.str; # TODO date's +FORMAT }; retain = mkOption { type = types.nullOr types.int; default = null; # null = retain all snapshots }; }; }); }; timerConfig = mkOption { type = with types; attrsOf str; default = optionalAttrs (config.startAt != null) { OnCalendar = config.startAt; }; }; }; })); }; }; imp = { krebs.on-failure.plans = listToAttrs (map (plan: nameValuePair "backup.${plan.name}" { }) (filter (plan: build-host-is "pull" "dst" plan || build-host-is "push" "src" plan) enabled-plans)); systemd.services = listToAttrs (map (plan: nameValuePair "backup.${plan.name}" { # TODO if there is plan.user, then use its privkey # TODO push destination users need a similar path path = with pkgs; [ coreutils gnused openssh rsync utillinux ]; restartIfChanged = false; serviceConfig = rec { ExecStart = start plan; SyslogIdentifier = ExecStart.name; Type = "oneshot"; }; }) (filter (plan: build-host-is "pull" "dst" plan || build-host-is "push" "src" plan) enabled-plans)); systemd.timers = listToAttrs (map (plan: nameValuePair "backup.${plan.name}" { wantedBy = [ "timers.target" ]; timerConfig = plan.timerConfig; }) (filter (plan: plan.timerConfig != {} && ( build-host-is "pull" "dst" plan || build-host-is "push" "src" plan)) enabled-plans)); users.groups.backup.gid = genid "backup"; users.users.root.openssh.authorizedKeys.keys = map (plan: getAttr plan.method { push = plan.src.host.ssh.pubkey; pull = plan.dst.host.ssh.pubkey; }) (filter (plan: build-host-is "pull" "src" plan || build-host-is "push" "dst" plan) enabled-plans); }; enabled-plans = filter (getAttr "enable") (attrValues cfg.plans); build-host-is = method: side: plan: plan.method == method && config.krebs.build.host.name == plan.${side}.host.name; start = plan: let login-name = "root"; identity = local.host.ssh.privkey.path; ssh = "ssh -i ${shell.escape identity}"; local = getAttr plan.method { push = plan.src // { rsync = src-rsync; }; pull = plan.dst // { rsync = dst-rsync; }; }; remote = getAttr plan.method { push = plan.dst // { rsync = dst-rsync; }; pull = plan.src // { rsync = src-rsync; }; }; src-rsync = "rsync"; dst-rsync = concatStringsSep " && " [ "stat ${shell.escape plan.dst.path} >/dev/null" "mkdir -m 0700 -p ${shell.escape plan.dst.path}/current" "flock -n ${shell.escape plan.dst.path} rsync" ]; in pkgs.writeBash "backup.${plan.name}" '' set -efu start_date=$(date +%s) ssh_target=${shell.escape login-name}@$(${fastest-address remote.host}) ${getAttr plan.method { push = '' rsync_src=${shell.escape plan.src.path} rsync_dst=$ssh_target:${shell.escape plan.dst.path} echo >&2 "update snapshot current; $rsync_src -> $rsync_dst" ''; pull = '' rsync_src=$ssh_target:${shell.escape plan.src.path} rsync_dst=${shell.escape plan.dst.path} echo >&2 "update snapshot current; $rsync_dst <- $rsync_src" ''; }} # In `dst-rsync`'s `mkdir m 0700 -p` above, we care only about permission # of the deepest directory: # shellcheck disable=SC2174 ${local.rsync} >&2 \ -aAXF --delete \ --rsh=${shell.escape ssh} \ --rsync-path=${shell.escape remote.rsync} \ --link-dest=${shell.escape plan.dst.path}/current \ "$rsync_src/" \ "$rsync_dst/.partial" dst_exec() { ${getAttr plan.method { push = ''exec ${ssh} "$ssh_target" -T "exec$(printf ' %q' "$@")"''; pull = ''exec "$@"''; }} } dst_exec env \ start_date="$start_date" \ flock -n ${shell.escape plan.dst.path} \ /bin/sh < ${toFile "backup.${plan.name}.take-snapshots" '' set -efu : $start_date dst_path=${shell.escape plan.dst.path} mv "$dst_path/current" "$dst_path/.previous" mv "$dst_path/.partial" "$dst_path/current" rm -fR "$dst_path/.previous" echo >&2 snapshot() {( : $ns $format $retain name=$(date --date="@$start_date" +"$format") if ! test -e "$dst_path/$ns/$name"; then echo >&2 "create snapshot: $ns/$name" mkdir -m 0700 -p "$dst_path/$ns" rsync >&2 \ -aAXF --delete \ --link-dest="$dst_path/current" \ "$dst_path/current/" \ "$dst_path/$ns/.partial.$name" mv "$dst_path/$ns/.partial.$name" "$dst_path/$ns/$name" echo >&2 fi case $retain in ([0-9]*) delete_from=$(($retain + 1)) ls -r "$dst_path/$ns" \ | sed -n "$delete_from,\$p" \ | while read old_name; do echo >&2 "delete snapshot: $ns/$old_name" rm -fR "$dst_path/$ns/$old_name" done ;; (ALL) : ;; esac )} ${concatStringsSep "\n" (mapAttrsToList (ns: { format, retain, ... }: toString (map shell.escape [ "ns=${ns}" "format=${format}" "retain=${if retain == null then "ALL" else toString retain}" "snapshot" ])) plan.snapshots)} ''} ''; # XXX Is one ping enough to determine fastest address? fastest-address = host: '' { ${pkgs.fping}/bin/fping