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Direktori : /lib/python3/dist-packages/cloudinit/ |
Current File : //lib/python3/dist-packages/cloudinit/atomic_helper.py |
# This file is part of cloud-init. See LICENSE file for license information. import json import logging import os import stat import tempfile from base64 import b64decode, b64encode _DEF_PERMS = 0o644 LOG = logging.getLogger(__name__) def b64d(source): # Base64 decode some data, accepting bytes or unicode/str, and returning # str/unicode if the result is utf-8 compatible, otherwise returning bytes. decoded = b64decode(source) try: return decoded.decode("utf-8") except UnicodeDecodeError: return decoded def b64e(source): # Base64 encode some data, accepting bytes or unicode/str, and returning # str/unicode if the result is utf-8 compatible, otherwise returning bytes. if not isinstance(source, bytes): source = source.encode("utf-8") return b64encode(source).decode("utf-8") def write_file( filename, content, mode=_DEF_PERMS, omode="wb", preserve_mode=False ): # open filename in mode 'omode', write content, set permissions to 'mode' if preserve_mode: try: file_stat = os.stat(filename) mode = stat.S_IMODE(file_stat.st_mode) except OSError: pass tf = None try: tf = tempfile.NamedTemporaryFile( dir=os.path.dirname(filename), delete=False, mode=omode ) LOG.debug( "Atomically writing to file %s (via temporary file %s) - %s: [%o]" " %d bytes/chars", filename, tf.name, omode, mode, len(content), ) tf.write(content) tf.close() os.chmod(tf.name, mode) os.rename(tf.name, filename) except Exception as e: if tf is not None: os.unlink(tf.name) raise e def json_serialize_default(_obj): """Handler for types which aren't json serializable.""" try: return "ci-b64:{0}".format(b64e(_obj)) except AttributeError: return "Warning: redacted unserializable type {0}".format(type(_obj)) def json_dumps(data): """Return data in nicely formatted json.""" return json.dumps( data, indent=1, sort_keys=True, separators=(",", ": "), default=json_serialize_default, ) def write_json(filename, data, mode=_DEF_PERMS): # dump json representation of data to file filename. return write_file( filename, json_dumps(data) + "\n", omode="w", mode=mode, )