143 lines
5.0 KiB
Python
143 lines
5.0 KiB
Python
# Copyright (c) 2014 Dark Secret Software Inc.
|
|
#
|
|
# Licensed under the Apache License, Version 2.0 (the "License");
|
|
# you may not use this file except in compliance with the License.
|
|
# You may obtain a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS,
|
|
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
|
|
# implied.
|
|
# See the License for the specific language governing permissions and
|
|
# limitations under the License.
|
|
|
|
import fnmatch
|
|
import os
|
|
import os.path
|
|
|
|
import archive
|
|
import disk_storage
|
|
import utils
|
|
|
|
|
|
class NoMoreFiles(Exception):
|
|
pass
|
|
|
|
|
|
class NoValidFile(Exception):
|
|
pass
|
|
|
|
|
|
class ArchiveCallback(object):
|
|
def on_open(self, filename):
|
|
"""Called when an Archive is opened."""
|
|
pass
|
|
|
|
def on_close(self, filename):
|
|
"""Called when an Archive is closed."""
|
|
pass
|
|
|
|
|
|
class RollManager(object):
|
|
def __init__(self, filename_template, directory=".",
|
|
archive_class=None, archive_callback=None):
|
|
self.filename_template = filename_template
|
|
self.directory = directory
|
|
self.active_archive = None
|
|
self.archive_class = archive_class
|
|
self.active_filename = None
|
|
self.archive_callback = archive_callback
|
|
|
|
def _roll_archive(self):
|
|
self.close()
|
|
self.get_active_archive()
|
|
|
|
def close(self):
|
|
if self.active_archive:
|
|
self.active_archive.close()
|
|
if self.archive_callback:
|
|
self.archive_callback.on_close(self.active_filename)
|
|
self.active_archive = None
|
|
self.active_filename = None
|
|
|
|
|
|
class ReadingRollManager(RollManager):
|
|
def __init__(self, filename_template, directory=".",
|
|
archive_class = archive.ArchiveReader,
|
|
archive_callback=None):
|
|
super(ReadingRollManager, self).__init__(
|
|
filename_template,
|
|
directory=directory,
|
|
archive_callback=archive_callback,
|
|
archive_class=archive_class)
|
|
self.files_to_read = self._get_matching_files(directory,
|
|
filename_template)
|
|
|
|
def _get_matching_files(self, directory, filename_template):
|
|
files = [os.path.join(directory, f)
|
|
for f in os.listdir(self.directory)
|
|
if os.path.isfile(os.path.join(directory, f))]
|
|
return sorted(fnmatch.filter(files, filename_template))
|
|
|
|
def read(self):
|
|
# (metadata, payload)
|
|
for x in range(3): # 3 attempts to file a valid file.
|
|
a = self.get_active_archive()
|
|
try:
|
|
return a.read()
|
|
except disk_storage.EndOfFile:
|
|
self._roll_archive()
|
|
raise NoValidFile("Unable to find a valid file after 3 attempts")
|
|
|
|
def get_active_archive(self):
|
|
if not self.active_archive:
|
|
if not self.files_to_read:
|
|
raise NoMoreFiles()
|
|
self.active_filename = self.files_to_read.pop(0)
|
|
self.active_archive = self.archive_class(self.active_filename)
|
|
if self.archive_callback:
|
|
self.archive_callback.on_open(self.active_filename)
|
|
return self.active_archive
|
|
|
|
|
|
class WritingRollManager(RollManager):
|
|
def __init__(self, filename_template, roll_checker, directory=".",
|
|
archive_class=archive.ArchiveWriter,
|
|
archive_callback=None):
|
|
super(WritingRollManager, self).__init__(
|
|
filename_template,
|
|
directory=directory,
|
|
archive_callback=archive_callback,
|
|
archive_class=archive_class)
|
|
self.roll_checker = roll_checker
|
|
|
|
def write(self, metadata, payload):
|
|
"""metadata is string:string dict.
|
|
payload must be encoded as string.
|
|
"""
|
|
a = self.get_active_archive()
|
|
a.write(metadata, payload)
|
|
if self._should_roll_archive():
|
|
self._roll_archive()
|
|
|
|
def _make_filename(self):
|
|
f = utils.now().strftime(self.filename_template)
|
|
f = f.replace(" ", "_")
|
|
f = f.replace("/", "_")
|
|
f = f.replace(":", "_")
|
|
return os.path.join(self.directory, f)
|
|
|
|
def get_active_archive(self):
|
|
if not self.active_archive:
|
|
self.active_filename = self._make_filename()
|
|
self.active_archive = self.archive_class(self.active_filename)
|
|
if self.archive_callback:
|
|
self.archive_callback.on_open(self.active_filename)
|
|
self.roll_checker.start(self.active_archive)
|
|
return self.active_archive
|
|
|
|
def _should_roll_archive(self):
|
|
return self.roll_checker.check(self.active_archive)
|