fix backups

2 files changed, 274 insertions, 87 deletions

diff --git a/hosts/vidhar/borg/borgsnap/borgsnap/__main__.py b/hosts/vidhar/borg/borgsnap/borgsnap/__main__.py
index e93e6a60..cd2f1ad2 100644
--- a/hosts/vidhar/borg/borgsnap/borgsnap/__main__.py
+++ b/hosts/vidhar/borg/borgsnap/borgsnap/__main__.py
@@ -1,12 +1,11 @@
 import argparse
-import os, sys, signal
-from pyprctl import cap_permitted, cap_inheritable, cap_effective, cap_ambient, Cap
+import os, sys, signal, io
+from pyprctl import CapState, Cap, cap_ambient_raise, cap_ambient_is_set, set_keepcaps
 from pwd import getpwnam
 
 from datetime import datetime, timezone
 from dateutil.parser import isoparse
 
-from xdg import xdg_runtime_dir
 import unshare
 from tempfile import TemporaryDirectory
 
@@ -14,6 +13,9 @@ import logging
 
 import json
 import subprocess
+import csv
+from collections import namedtuple
+from distutils.util import strtobool
 
 import pathlib
 from pathlib import Path
@@ -22,21 +24,89 @@ from atomicwrites import atomic_write
 
 from traceback import format_exc
 
+from multiprocessing import Process, Manager
+from contextlib import closing
+
+from enum import Enum, auto
+
+import select
+import time
+import math
+
+
+PROP_DO_BORGSNAP = 'li.yggdrasil:borgsnap'
+
+
+class DoValue(Enum):
+    BORGSNAP_DO = auto()
+    BORGSNAP_KEEP = auto()
+    BORGSNAP_DONT = auto()
+
+    @classmethod
+    def from_prop(cls, v: str):
+        if v.lower() == 'keep':
+            return cls.BORGSNAP_KEEP
+
+        return cls.BORGSNAP_DO if not v or bool(strtobool(v)) else cls.BORGSNAP_DONT
+
+    @classmethod
+    def merge(cls, v1, v2):
+        match (v1, v2):
+            case (cls.BORGSNAP_DONT, _):
+                return cls.BORGSNAP_DONT
+            case (_, cls.BORGSNAP_DONT):
+                return cls.BORGSNAP_DONT
+            case (cls.BORGSNAP_KEEP, _):
+                return cls.BORGSNAP_KEEP
+            case (_, cls.BORGSNAP_KEEP):
+                return cls.BORGSNAP_KEEP
+            case other:
+                return cls.BORGSNAP_DO
+
+    def returncode(self):
+        match self:
+            case self.__class__.BORGSNAP_DO:
+                return 126
+            case self.__class__.BORGSNAP_KEEP:
+                return 125
+            case self.__class__.BORGSNAP_DONT:
+                return 124
 
 borg_pwd = getpwnam('borg')
 
-def as_borg(caps=set(), cwd=None):
-    if caps:
-        cap_permitted.add(*caps)
-        cap_inheritable.add(*caps)
-        cap_effective.add(*caps)
-        cap_ambient.add(*caps)
+def as_borg(caps=set()):
+    global logger
+
+    try:
+        if caps:
+            c_state = CapState.get_current()
+            c_state.permitted.add(*caps)
+            c_state.set_current()
+
+            logger.debug("before setgid/setuid: cap_permitted=%s", CapState.get_current().permitted)
+
+            set_keepcaps(True)
+
+        os.setgid(borg_pwd.pw_gid)
+        os.setuid(borg_pwd.pw_uid)
 
-    os.setgid(borg_pwd.pw_gid)
-    os.setuid(borg_pwd.pw_uid)
+        if caps:
+            logger.debug("after setgid/setuid: cap_permitted=%s", CapState.get_current().permitted)
 
-    if cwd is not None:
-        os.chdir(cwd)
+            c_state = CapState.get_current()
+            c_state.permitted = caps.copy()
+            c_state.inheritable.add(*caps)
+            c_state.set_current()
+
+            logger.debug("cap_permitted=%s", CapState.get_current().permitted)
+            logger.debug("cap_inheritable=%s", CapState.get_current().inheritable)
+
+            for cap in caps:
+                cap_ambient_raise(cap)
+                logger.debug("cap_ambient[%s]=%s", cap, cap_ambient_is_set(cap))
+    except Exception:
+        logger.error(format_exc())
+        raise
 
 
 def _archive_name(snapshot, target, archive_prefix):
@@ -50,13 +120,15 @@ def _archive_basename(snapshot, archive_prefix):
     return archive_prefix + base_name.replace('-', '--').replace('/', '-')
 
 def check(*, snapshot, target, archive_prefix, cache_file):
+    global logger
+
     archives = None
     if cache_file:
         logger.debug('Trying cache...')
         try:
             with open(cache_file, mode='r', encoding='utf-8') as fp:
                 archives = set(json.load(fp))
-            logger.info('Loaded archive list from cache')
+            logger.debug('Loaded archive list from cache')
         except FileNotFoundError:
             pass
 
@@ -72,76 +144,165 @@ def check(*, snapshot, target, archive_prefix, cache_file):
     # logger.debug(f'archives: {archives}')
     _, _, archive_name = _archive_name(snapshot, target, archive_prefix).partition('::')
     if archive_name in archives:
-        logger.info(f'{archive_name} found')
+        logger.info('‘%s’ found', archive_name)
         return 0
     else:
-        logger.info(f'{archive_name} not found')
-        return 126
+        logger.info('‘%s’ not found', archive_name)
+
+        logger.debug('Checking %s for ‘%s’...', PROP_DO_BORGSNAP, snapshot)
+        intent = DoValue.BORGSNAP_DO
+        p = subprocess.run(['zfs', 'get', '-H', '-p', '-o', 'name,value', PROP_DO_BORGSNAP, snapshot], stdout=subprocess.PIPE, text=True, check=True)
+        reader = csv.DictReader(io.StringIO(p.stdout), fieldnames=['name', 'value'], delimiter='\t', quoting=csv.QUOTE_NONE)
+        Row = namedtuple('Row', reader.fieldnames)
+        for row in [Row(**data) for data in reader]:
+            if not row.value or row.value == '-':
+                continue
+
+            logger.debug('%s=%s (parsed as %s) for ‘%s’...', PROP_DO_BORGSNAP, row.value, DoValue.from_prop(row.value), row.name)
+            intent = DoValue.merge(intent, DoValue.from_prop(row.value))
+
+        match intent:
+            case DoValue.BORGSNAP_DONT:
+                logger.warn('%s specifies to ignore, returning accordingly...', PROP_DO_BORGSNAP)
+            case DoValue.BORGSNAP_KEEP:
+                logger.info('%s specifies to ignore but keep, returning accordingly...', PROP_DO_BORGSNAP)
+            case other:
+                pass
+
+        return intent.returncode()
 
 def create(*, snapshot, target, archive_prefix, dry_run):
+    global logger
+
     basename = _archive_basename(snapshot, archive_prefix)
 
-    with TemporaryDirectory(prefix=f'borg-mount_{basename}_', dir=os.environ.get('RUNTIME_DIRECTORY')) as tmpdir:
-        child = os.fork()
-        if child == 0:
-            unshare.unshare(unshare.CLONE_NEWNS)
-            subprocess.run(['mount', '--make-rprivate', '/'], check=True)
-            chroot = pathlib.Path(tmpdir) / 'chroot'
-            upper = pathlib.Path(tmpdir) / 'upper'
-            work = pathlib.Path(tmpdir) / 'work'
-            for path in [chroot,upper,work]:
-                path.mkdir()
-            subprocess.run(['mount', '-t', 'overlay', 'overlay', '-o', f'lowerdir=/,upperdir={upper},workdir={work}', chroot], check=True)
-            bindMounts = ['nix', 'run', 'run/secrets.d', 'run/wrappers', 'proc', 'dev', 'sys', pathlib.Path(os.path.expanduser('~')).relative_to('/')]
-            if os.environ.get('BORG_BASE_DIR'):
-                bindMounts.append(pathlib.Path(os.environ['BORG_BASE_DIR']).relative_to('/'))
-            if 'SSH_AUTH_SOCK' in os.environ:
-                bindMounts.append(pathlib.Path(os.environ['SSH_AUTH_SOCK']).parent.relative_to('/'))
-            for bindMount in bindMounts:
-                (chroot / bindMount).mkdir(parents=True,exist_ok=True)
-                # print(*['mount', '--bind', pathlib.Path('/') / bindMount, chroot / bindMount], file=stderr)
-                subprocess.run(['mount', '--bind', pathlib.Path('/') / bindMount, chroot / bindMount], check=True)
-            os.chroot(chroot)
-            os.chdir('/')
-            dir = pathlib.Path('/borg')
-            dir.mkdir(parents=True,exist_ok=True,mode=0o0750)
-            os.chown(dir, borg_pwd.pw_uid, borg_pwd.pw_gid)
-            try:
+    def do_create(tmpdir_q):
+        global logger
+        nonlocal basename, snapshot, target, archive_prefix, dry_run
+
+        tmpdir = tmpdir_q.get()
+
+        unshare.unshare(unshare.CLONE_NEWNS)
+        subprocess.run(['mount', '--make-rprivate', '/'], check=True)
+        chroot = pathlib.Path(tmpdir) / 'chroot'
+        upper = pathlib.Path(tmpdir) / 'upper'
+        work = pathlib.Path(tmpdir) / 'work'
+        for path in [chroot,upper,work]:
+            path.mkdir()
+        subprocess.run(['mount', '-t', 'overlay', 'overlay', '-o', f'lowerdir=/,upperdir={upper},workdir={work}', chroot], check=True)
+        bindMounts = ['nix', 'run', 'run/secrets.d', 'run/wrappers', 'proc', 'dev', 'sys', pathlib.Path(os.path.expanduser('~')).relative_to('/')]
+        if borg_base_dir := os.getenv('BORG_BASE_DIR'):
+            bindMounts.append(pathlib.Path(borg_base_dir).relative_to('/'))
+        if ssh_auth_sock := os.getenv('SSH_AUTH_SOCK'):
+            bindMounts.append(pathlib.Path(ssh_auth_sock).parent.relative_to('/'))
+        for bindMount in bindMounts:
+            (chroot / bindMount).mkdir(parents=True,exist_ok=True)
+            subprocess.run(['mount', '--bind', pathlib.Path('/') / bindMount, chroot / bindMount], check=True)
+
+        os.chroot(chroot)
+        os.chdir('/')
+        dir = pathlib.Path('/borg')
+        dir.mkdir(parents=True,exist_ok=True,mode=0o0750)
+        os.chown(dir, borg_pwd.pw_uid, borg_pwd.pw_gid)
+
+        base_name, _, _ = snapshot.rpartition('@')
+        type_val = subprocess.run(['zfs', 'get', '-H', '-p', '-o', 'value', 'type', base_name], stdout=subprocess.PIPE, text=True, check=True).stdout.strip()
+        match type_val:
+            case 'filesystem':
                 subprocess.run(['mount', '-t', 'zfs', '-o', 'ro', snapshot, dir], check=True)
-                env = os.environ.copy()
-                create_args = ['borg',
-                               'create',
-                               '--lock-wait=600',
-                               '--one-file-system',
-                               '--compression=auto,zstd,10',
-                               '--chunker-params=10,23,16,4095',
-                               '--files-cache=ctime,size',
-                               '--show-rc',
-                               # '--remote-ratelimit=20480',
-                               '--progress',
-                               '--list',
-                               '--filter=AMEi-x?',
-                               '--stats' if not dry_run else '--dry-run'
-                               ]
-                _, _, ts = snapshot.rpartition('@')
-                creation_time = isoparse(ts).astimezone(timezone.utc)
-                create_args += [f'--timestamp={creation_time.strftime("%Y-%m-%dT%H:%M:%S")}']
-                env['BORG_FILES_CACHE_SUFFIX'] = basename
-                create_args += [_archive_name(snapshot, target, archive_prefix), '.']
-                print({'create_args': create_args, 'cwd': dir, 'env': env}, file=sys.stderr)
-                subprocess.run(create_args, stdin=subprocess.DEVNULL, env=env, preexec_fn=lambda: as_borg(caps={CAP.DAC_READ_SEARCH}, cwd=dir), check=True)
-                #  subprocess.run(create_args, stdin=subprocess.DEVNULL, env=env, preexec_fn=lambda: None, cwd=dir, check=True)
-            finally:
-                subprocess.run(['umount', dir], check=True)
-            os._exit(0)
+            case 'volume':
+                snapdev_val = subprocess.run(['zfs', 'get', '-H', '-p', '-o', 'value', 'snapdev', base_name], stdout=subprocess.PIPE, text=True, check=True).stdout.strip()
+                try:
+                    if snapdev_val == 'hidden':
+                        subprocess.run(['zfs', 'set', 'snapdev=visible', base_name], check=True)
+                    subprocess.run(['mount', '-t', 'auto', '-o', 'ro', Path('/dev/zvol') / snapshot, dir], check=True)
+                finally:
+                    if snapdev_val == 'hidden':
+                        subprocess.run(['zfs', 'inherit', 'snapdev', base_name], check=True)
+            case other:
+                raise ValueError(f'‘{base_name}’ is of type ‘{type_val}’')
+
+        env = os.environ.copy()
+        create_args = ['borg',
+                       'create',
+                       '--lock-wait=600',
+                       '--one-file-system',
+                       '--exclude-caches',
+                       '--keep-exclude-tags',
+                       '--compression=auto,zstd,10',
+                       '--chunker-params=10,23,16,4095',
+                       '--files-cache=ctime,size',
+                       '--show-rc',
+                       # '--remote-ratelimit=20480',
+                       '--progress',
+                       '--list',
+                       '--filter=AMEi-x?',
+                       '--stats' if not dry_run else '--dry-run',
+                       ]
+        _, _, ts = snapshot.rpartition('@')
+        creation_time = isoparse(ts).astimezone(timezone.utc)
+        create_args += [f'--timestamp={creation_time.strftime("%Y-%m-%dT%H:%M:%S")}']
+        env['BORG_FILES_CACHE_SUFFIX'] = basename
+        archive_name = _archive_name(snapshot, target, archive_prefix)
+        target_host, _, target_path = target.rpartition(':')
+        *parents_init, _ = list(Path(target_path).parents)
+        backup_patterns = [*(map(lambda p: Path('.backup') / f'{target_host}:{p}', [Path(target_path), *parents_init])), Path('.backup') / target_host, Path('.backup')]
+        for pattern_file in backup_patterns:
+            if (dir / pattern_file).is_file():
+                logger.debug('Found backup patterns at ‘%s’', dir / pattern_file)
+                create_args += [f'--patterns-from={pattern_file}', archive_name]
+                break
+            elif (dir / pattern_file).exists():
+                logger.warn('‘%s’ exists but is no file', dir / pattern_file)
         else:
-            while True:
-                waitpid, waitret = os.wait()
-                if waitret != 0:
-                    sys.exit(waitret)
-                if waitpid == child:
-                    break
-    return 0
+            logger.debug('No backup patterns exist, checked %s', list(map(lambda pattern_file: str(dir / pattern_file), backup_patterns)))
+            create_args += [archive_name, '.']
+        logger.debug('%s', {'create_args': create_args, 'cwd': dir, 'env': env})
+
+        with subprocess.Popen(create_args, stdin=subprocess.DEVNULL, stdout=subprocess.PIPE, stderr=subprocess.PIPE, env=env, preexec_fn=lambda: as_borg(caps={Cap.DAC_READ_SEARCH}), cwd=dir, text=True) as proc:
+            proc_logger = logger.getChild('borg')
+
+            poll = select.poll()
+            poll.register(proc.stdout, select.POLLIN | select.POLLHUP)
+            poll.register(proc.stderr, select.POLLIN | select.POLLHUP)
+            pollc = 2
+            events = poll.poll()
+            while pollc > 0 and len(events) > 0:
+                for rfd, event in events:
+                    if event & select.POLLIN:
+                        if rfd == proc.stdout.fileno():
+                            line = proc.stdout.readline()
+                            if len(line) > 0:
+                                proc_logger.info(line[:-1])
+                        if rfd == proc.stderr.fileno():
+                            line = proc.stderr.readline()
+                            if len(line) > 0:
+                                proc_logger.info(line[:-1])
+                    if event & select.POLLHUP:
+                        poll.unregister(rfd)
+                        pollc -= 1
+
+                if pollc > 0:
+                    events = poll.poll()
+
+            for handler in proc_logger.handlers:
+                handler.flush()
+
+            ret = proc.wait()
+            if ret != 0:
+                raise Exception(f'borg subprocess exited with returncode {ret}')
+
+    with Manager() as manager:
+        tmpdir_q = manager.Queue(1)
+        with closing(Process(target=do_create, args=(tmpdir_q,), name='do_create')) as p:
+            p.start()
+
+            with TemporaryDirectory(prefix=f'borg-mount_{basename}_', dir=os.getenv('RUNTIME_DIRECTORY')) as tmpdir:
+                tmpdir_q.put(tmpdir)
+                p.join()
+                if p.exitcode == 0 and dry_run:
+                    return 125
+                return p.exitcode
 
 def sigterm(signum, frame):
     raise SystemExit(128 + signum)
@@ -155,6 +316,32 @@ def main():
     console_handler.setFormatter( logging.Formatter('[%(levelname)s](%(name)s): %(message)s') )
     if sys.stderr.isatty():
         console_handler.setFormatter( logging.Formatter('%(asctime)s [%(levelname)s](%(name)s): %(message)s') )
+
+    burst_max = 10000
+    burst = burst_max
+    last_use = None
+    inv_rate = 1e6
+    def consume_filter(record):
+        nonlocal burst, burst_max, inv_rate, last_use
+
+        delay = None
+        while True:
+            now = time.monotonic_ns()
+            burst = min(burst_max, burst + math.floor((now - last_use) / inv_rate)) if last_use else burst_max
+            last_use = now
+
+            if burst > 0:
+                burst -= 1
+                if delay:
+                    delay = now - delay
+
+                return True
+
+            if delay is None:
+                delay = now
+            time.sleep(inv_rate / 1e9)
+    console_handler.addFilter(consume_filter)
+
     logger.addHandler(console_handler)
 
     # log uncaught exceptions
@@ -167,7 +354,8 @@ def main():
     sys.excepthook = log_exceptions
 
     parser = argparse.ArgumentParser(prog='borgsnap')
-    parser.add_argument('--verbose', '-v', action='count', default=0)
+    parser.add_argument('--verbose', '-v', dest='log_level', action='append_const', const=-1)
+    parser.add_argument('--quiet', '-q', dest='log_level', action='append_const', const=1)
     parser.add_argument('--target', metavar='REPO', default='yggdrasil.borgbase:repo')
     parser.add_argument('--archive-prefix', metavar='REPO', default='yggdrasil.vidhar.')
     subparsers = parser.add_subparsers()
@@ -183,12 +371,13 @@ def main():
     create_parser.set_defaults(cmd=create)
     args = parser.parse_args()
 
-    if args.verbose <= 0:
-        logger.setLevel(logging.WARNING)
-    elif args.verbose <= 1:
-        logger.setLevel(logging.INFO)
-    else:
-        logger.setLevel(logging.DEBUG)
+    LOG_LEVELS = [logging.DEBUG, logging.INFO, logging.WARNING, logging.ERROR, logging.CRITICAL]
+    DEFAULT_LOG_LEVEL = logging.ERROR
+    log_level = LOG_LEVELS.index(DEFAULT_LOG_LEVEL)
+
+    for adjustment in args.log_level or ():
+        log_level = min(len(LOG_LEVELS) - 1, max(log_level + adjustment, 0))
+    logger.setLevel(LOG_LEVELS[log_level])
 
     cmdArgs = {}
     for copy in {'target', 'archive_prefix', 'snapshot', 'cache_file', 'dry_run'}:
diff --git a/hosts/vidhar/borg/default.nix b/hosts/vidhar/borg/default.nix
index 79c75c4d..7e3129f2 100644
--- a/hosts/vidhar/borg/default.nix
+++ b/hosts/vidhar/borg/default.nix
@@ -74,7 +74,7 @@ let
         copy
 
       wrapProgram $out/bin/copy \
-        --prefix PATH : ${makeBinPath (with pkgs; [util-linux borgbackup])}:${config.security.wrapperDir}
+        --prefix PATH : ${makeBinPath (with pkgs; [config.boot.zfs.package util-linux borgbackup])}:${config.security.wrapperDir}
     '';
   });
 
@@ -88,7 +88,6 @@ let
       atomicwrites
       pyprctl
       python-unshare
-      xdg
       python-dateutil
     '';
     postInstall = ''
@@ -101,14 +100,13 @@ let
       (self: super: { python-unshare = super.python-unshare.overrideAttrs (oldAttrs: { name = "python-unshare-0.2.1"; version = "0.2.1"; }); })
     ];
 
-    _.xdg.buildInputs.add = with pkgs."python3Packages"; [ poetry ];
     _.tomli.buildInputs.add = with pkgs."python3Packages"; [ flit-core ];
   };
 in {
   config = {
     services.zfssnap.config.exec = {
       check = "${borgsnap}/bin/borgsnap -vvv --target yggdrasil.borgbase:repo --archive-prefix yggdrasil.vidhar. check --cache-file /run/zfssnap-prune/archives-cache.json";
-      cmd = "${borgsnap}/bin/borgsnap -vvv --target yggdrasil.borgbase:repo --archive-prefix yggdrasil.vidhar. create --dry-run";
+      cmd = "${borgsnap}/bin/borgsnap -vvv --target yggdrasil.borgbase:repo --archive-prefix yggdrasil.vidhar. create";
 
       halfweekly = "8";
       monthly = "-1";