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- #!.venv/bin/python
-
- # Scan filesystem to generate a list of files to back up, based on a
- # configuration file. Pass this list to borg to actually create the
- # backup. Execute a notification script on the remote server to
- # report the backup status.
-
- import os
- import re
- import sys
- import stat
- import time
- import pathlib
- import subprocess
-
- import typing
-
- import yaml
- import wcmatch.glob # type: ignore
- import humanfriendly # type: ignore
-
- def pstr(path: bytes) -> str:
- return path.decode(errors='backslashreplace')
-
- class Config:
- root: bytes
- max_file_size: typing.Optional[int]
- one_file_system: bool
- exclude_caches: bool
- exclude: list[bytes]
- force_include: list[bytes]
- notify_email: typing.Optional[str]
-
- def __init__(self, configfile: str):
- # Read config
- with open(configfile, 'r') as f:
- config = yaml.safe_load(f)
- self.root = config['root'].encode()
- self.one_file_system = config.get('one-file-system', False)
- self.exclude_caches = config.get('exclude-caches', False)
-
- if 'max-file-size' in config:
- self.max_file_size = humanfriendly.parse_size(
- config['max-file-size'])
- else:
- self.max_file_size = None
-
- def process_match_list(config_name):
- raw = config.get(config_name, '').encode().split(b'\n')
- pats = []
- # Prepend '**/' to any relative patterns
- for x in raw:
- if not len(x):
- continue
- if x.startswith(b'/'):
- pats.append(x)
- else:
- pats.append(b'**/' + x)
- return pats
-
- self.exclude = process_match_list('exclude')
- self.force_include = process_match_list('force-include')
-
- self.notify_email = config.get('notify-email', None)
-
- # Compile patterns
- flags = (wcmatch.glob.GLOBSTAR |
- wcmatch.glob.DOTGLOB |
- wcmatch.glob.NODOTDIR |
- wcmatch.glob.EXTGLOB |
- wcmatch.glob.BRACE)
-
- # Path matches if it matches at least one regex in "a" and no
- # regex in "b"
- (a, b) = wcmatch.glob.translate(self.exclude, flags=flags)
- self.exclude_re = ([ re.compile(x) for x in a ],
- [ re.compile(x) for x in b ])
-
- (a, b) = wcmatch.glob.translate(self.force_include, flags=flags)
- self.force_include_re = ([ re.compile(x) for x in a ],
- [ re.compile(x) for x in b ])
-
- def match_re(self, re: tuple[list[typing.Pattern],
- list[typing.Pattern]], path: bytes):
- # Path matches if it matches at least one regex in
- # re[0] and no regex in re[1].
- for a in re[0]:
- if a.match(path):
- for b in re[1]:
- if b.match(path):
- return False
- return True
- return False
-
- class Backup:
- def __init__(self, config: Config, dry_run: bool):
- self.config = config
- self.dry_run = dry_run
-
- # All logged messages, with severity
- self.logs: list[tuple[str, str]] = []
-
- def out(self, path: bytes):
- self.outfile.write(path + (b'\n' if self.dry_run else b'\0'))
-
- def log(self, letter: str, msg: str):
- colors = { 'E': 31, 'W': 33, 'I': 36 };
- if letter in colors:
- c = colors[letter]
- else:
- c = 0
- sys.stderr.write(f"\033[1;{c}m{letter}:\033[22m {msg}\033[0m\n")
- self.logs.append((letter, msg))
-
- def run(self, outfile: typing.IO[bytes]):
- self.outfile = outfile
- # Base should not end with a slash, but full path should
- if self.config.root.endswith(b'/'):
- base = self.config.root[:-1]
- path = self.config.root
- else:
- base = self.config.root
- path = self.config.root + b'/'
- self.scan(base, path)
-
- def scan(self, base: bytes, path: bytes,
- parent_st: os.stat_result=None):
- """If the given path should be backed up, print it. If it's
- a directory and its contents should be included, recurse.
- """
-
- if base.endswith(b'/'):
- raise Exception("base must not end with /")
- relpath = path[len(base):]
- if not relpath.startswith(b'/'):
- raise Exception(f"relative path (from {repr(base)}, {repr(path)})"
- + f" must start with /")
-
- try:
- st = os.lstat(path)
- is_dir = stat.S_ISDIR(st.st_mode)
- is_reg = stat.S_ISREG(st.st_mode)
- size = st.st_blocks * 512
-
- # Decorated path ends with a '/' if it's a directory.
- decorated_path = path
- if is_dir and not decorated_path.endswith(b'/'):
- decorated_path += b'/'
-
- # See if there's a reason to exclude it
- exclude_reason = None
-
- if self.config.match_re(self.config.exclude_re, decorated_path):
- # Config file says to exclude
- exclude_reason = ('I', f"skipping, excluded by config file")
-
- elif (self.config.one_file_system
- and parent_st is not None
- and is_dir
- and st.st_dev != parent_st.st_dev):
- # Crosses a mount point
- exclude_reason = ('I', "skipping, on different filesystem")
-
- elif (is_reg
- and self.config.max_file_size
- and size > self.config.max_file_size):
- # Too big
- def format_size(n):
- return humanfriendly.format_size(
- n, keep_width=True, binary=True)
- a = format_size(size)
- b = format_size(self.config.max_file_size)
- exclude_reason = ('W', f"file size {a} exceeds limit {b}")
-
- # If we have a reason to exclude it, stop now unless it's
- # force-included
- force = self.config.match_re(self.config.force_include_re,
- decorated_path)
- if exclude_reason and not force:
- self.log(exclude_reason[0],
- f"{exclude_reason[1]}: {pstr(path)}")
- return
-
- # Print path for Borg
- self.out(path)
-
- # Process directories
- if is_dir:
-
- # Skip if it contains CACHEDIR.TAG
- # (mirroring the --exclude-caches borg option)
- if self.config.exclude_caches:
- try:
- tag = b'Signature: 8a477f597d28d172789f06886806bc55'
- with open(path + b'/CACHEDIR.TAG', 'rb') as f:
- if f.read(len(tag)) == tag:
- self.log(
- 'I', f"skipping, cache dir: {pstr(path)}")
- return
- except:
- pass
-
- # Recurse
- with os.scandir(path) as it:
- for entry in it:
- self.scan(base=base, path=entry.path,
- parent_st=st)
-
- except PermissionError as e:
- self.log('E', f"can't read {pstr(path)}")
- return
-
- def main(argv: list[str]):
- import argparse
-
- def humansize(string):
- return humanfriendly.parse_size(string)
-
- parser = argparse.ArgumentParser(
- prog=argv[0],
- description="Back up the local system using borg",
- formatter_class=argparse.ArgumentDefaultsHelpFormatter)
-
- base = pathlib.Path(__file__).parent
- parser.add_argument('-c', '--config',
- help="Config file", default=str(base / "config.yaml"))
- parser.add_argument('-b', '--borg',
- help="Borg command", default=str(base / "borg.sh"))
- parser.add_argument('-n', '--dry-run', action="store_true",
- help="Just print log output, don't run borg")
- parser.add_argument('-d', '--debug', action="store_true",
- help="Print filenames for --dry-run")
-
- args = parser.parse_args()
- config = Config(args.config)
-
- backup = Backup(config, args.dry_run)
- if args.dry_run:
- if args.debug:
- backup.run(sys.stdout.buffer)
- else:
- with open(os.devnull, "wb") as out:
- backup.run(out)
- else:
- borg = subprocess.Popen([args.borg,
- "create",
- "--verbose",
- "--list",
- "--filter", "E",
- "--stats",
- "--checkpoint-interval", "900",
- "--compression", "zstd,3",
- "--paths-from-stdin",
- "--paths-delimiter", "\\0",
- "::'{hostname}-{now:%Y%m%d-%H%M%S}'"],
- stdin=subprocess.PIPE)
- if borg.stdin is None:
- raise Exception("no pipe")
- try:
- # Give borg some time to start, just to clean up stdout
- time.sleep(2)
- backup.run(borg.stdin)
- except BrokenPipeError:
- sys.stderr.write(f"broken pipe\n")
- finally:
- try:
- borg.stdin.close()
- except BrokenPipeError:
- pass
- borg.wait()
- ret = borg.returncode
- if ret < 0:
- sys.stderr.write(f"error: process exited with signal {-ret}\n")
- return 1
- elif ret != 0:
- sys.stderr.write(f"error: process exited with return code {ret}\n")
- return ret
-
- return 0
-
- if __name__ == "__main__":
- import sys
- raise SystemExit(main(sys.argv))
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