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quay/config_app/config_util/config/TransientDirectoryProvider.py
2019-11-12 11:09:47 -05:00

62 lines
2.2 KiB
Python

import os
from shutil import copytree
from backports.tempfile import TemporaryDirectory
from config_app.config_util.config.fileprovider import FileConfigProvider
OLD_CONFIG_SUBDIR = 'old/'
class TransientDirectoryProvider(FileConfigProvider):
""" Implementation of the config provider that reads and writes the data
from/to the file system, only using temporary directories,
deleting old dirs and creating new ones as requested.
"""
def __init__(self, config_volume, yaml_filename, py_filename):
# Create a temp directory that will be cleaned up when we change the config path
# This should ensure we have no "pollution" of different configs:
# no uploaded config should ever affect subsequent config modifications/creations
temp_dir = TemporaryDirectory()
self.temp_dir = temp_dir
self.old_config_dir = None
super(TransientDirectoryProvider, self).__init__(temp_dir.name, yaml_filename, py_filename)
@property
def provider_id(self):
return 'transient'
def new_config_dir(self):
"""
Update the path with a new temporary directory, deleting the old one in the process
"""
self.temp_dir.cleanup()
temp_dir = TemporaryDirectory()
self.config_volume = temp_dir.name
self.temp_dir = temp_dir
self.yaml_path = os.path.join(temp_dir.name, self.yaml_filename)
def create_copy_of_config_dir(self):
"""
Create a directory to store loaded/populated configuration (for rollback if necessary)
"""
if self.old_config_dir is not None:
self.old_config_dir.cleanup()
temp_dir = TemporaryDirectory()
self.old_config_dir = temp_dir
# Python 2.7's shutil.copy() doesn't allow for copying to existing directories,
# so when copying/reading to the old saved config, we have to talk to a subdirectory,
# and use the shutil.copytree() function
copytree(self.config_volume, os.path.join(temp_dir.name, OLD_CONFIG_SUBDIR))
def get_config_dir_path(self):
return self.config_volume
def get_old_config_dir(self):
if self.old_config_dir is None:
raise Exception('Cannot return a configuration that was no old configuration')
return os.path.join(self.old_config_dir.name, OLD_CONFIG_SUBDIR)