nsconfig/daemon/__init__.py

   1 # PyNSC: Generic interface for generating daemon configuration
   2 # (c) 2024 Martin Mareš <mj@ucw.cz>
   3
   4 from io import StringIO
   5 from pathlib import Path
   6 from typing import TextIO
   7 import subprocess
   8 import sys
   9
  10 from nsconfig.core import Nsc, NscZone
  11
  12
  13 class NscDaemon:
  14     nsc: Nsc
  15
  16     def __init__(self) -> None:
  17         pass
  18
  19     def setup(self, nsc: Nsc) -> None:
  20         self.nsc = nsc
  21
  22     def dump_config(self, file: TextIO = sys.stdout) -> None:
  23         pass
  24
  25     def write_config(self) -> None:
  26         pass
  27
  28     def reload_zone(self, z: NscZone) -> None:
  29         pass
  30
  31     def reload_daemon(self) -> None:
  32         pass
  33
  34     def _install_config(self, path: Path, new_contents: str) -> bool:
  35         try:
  36             old_new_contents = path.read_text()
  37         except FileNotFoundError:
  38             old_new_contents = None
  39         if new_contents == old_new_contents:
  40             return False
  41         else:
  42             new_path = Path(str(path) + '.new')
  43             with open(new_path, 'w') as f:
  44                 f.write(new_contents)
  45             new_path.replace(path)
  46             return True
  47
  48     def _write_config(self, config_path: Path) -> bool:
  49         string_stream = StringIO()
  50         self.dump_config(string_stream)
  51         if self._install_config(config_path, string_stream.getvalue()):
  52             print('Wrote new daemon configuration')
  53             return True
  54         else:
  55             print('Daemon configuration not changed')
  56             return False
  57
  58     def _run_command(self, argv, **kwargs) -> None:
  59         res = subprocess.run(argv, **kwargs)
  60         if res.returncode > 0:
  61             print(f'Command failed: {argv}')
  62             sys.exit(1)
  63
  64
  65 class NscDaemonNull(NscDaemon):
  66     pass