134 lines
4.5 KiB
Python
134 lines
4.5 KiB
Python
|
# coding: utf-8
|
||
|
|
"""Manager to read and modify config data in JSON files."""
|
||
|
|
|
||
|
|
# Copyright (c) Jupyter Development Team.
|
||
|
|
# Distributed under the terms of the Modified BSD License.
|
||
|
|
|
||
|
|
import errno
|
||
|
|
import glob
|
||
|
|
import io
|
||
|
|
import json
|
||
|
|
import os
|
||
|
|
import copy
|
||
|
|
|
||
|
|
from traitlets.config import LoggingConfigurable
|
||
|
|
from traitlets.traitlets import Unicode, Bool
|
||
|
|
|
||
|
|
|
||
|
|
def recursive_update(target, new):
|
||
|
|
"""Recursively update one dictionary using another.
|
||
|
|
|
||
|
|
None values will delete their keys.
|
||
|
|
"""
|
||
|
|
for k, v in new.items():
|
||
|
|
if isinstance(v, dict):
|
||
|
|
if k not in target:
|
||
|
|
target[k] = {}
|
||
|
|
recursive_update(target[k], v)
|
||
|
|
if not target[k]:
|
||
|
|
# Prune empty subdicts
|
||
|
|
del target[k]
|
||
|
|
|
||
|
|
elif v is None:
|
||
|
|
target.pop(k, None)
|
||
|
|
|
||
|
|
else:
|
||
|
|
target[k] = v
|
||
|
|
|
||
|
|
|
||
|
|
def remove_defaults(data, defaults):
|
||
|
|
"""Recursively remove items from dict that are already in defaults"""
|
||
|
|
# copy the iterator, since data will be modified
|
||
|
|
for key, value in list(data.items()):
|
||
|
|
if key in defaults:
|
||
|
|
if isinstance(value, dict):
|
||
|
|
remove_defaults(data[key], defaults[key])
|
||
|
|
if not data[key]: # prune empty subdicts
|
||
|
|
del data[key]
|
||
|
|
else:
|
||
|
|
if value == defaults[key]:
|
||
|
|
del data[key]
|
||
|
|
|
||
|
|
|
||
|
|
class BaseJSONConfigManager(LoggingConfigurable):
|
||
|
|
"""General JSON config manager
|
||
|
|
|
||
|
|
Deals with persisting/storing config in a json file with optionally
|
||
|
|
default values in a {section_name}.d directory.
|
||
|
|
"""
|
||
|
|
|
||
|
|
config_dir = Unicode('.')
|
||
|
|
read_directory = Bool(True)
|
||
|
|
|
||
|
|
def ensure_config_dir_exists(self):
|
||
|
|
"""Will try to create the config_dir directory."""
|
||
|
|
try:
|
||
|
|
os.makedirs(self.config_dir, 0o755)
|
||
|
|
except OSError as e:
|
||
|
|
if e.errno != errno.EEXIST:
|
||
|
|
raise
|
||
|
|
|
||
|
|
def file_name(self, section_name):
|
||
|
|
"""Returns the json filename for the section_name: {config_dir}/{section_name}.json"""
|
||
|
|
return os.path.join(self.config_dir, section_name+'.json')
|
||
|
|
|
||
|
|
def directory(self, section_name):
|
||
|
|
"""Returns the directory name for the section name: {config_dir}/{section_name}.d"""
|
||
|
|
return os.path.join(self.config_dir, section_name+'.d')
|
||
|
|
|
||
|
|
def get(self, section_name, include_root=True):
|
||
|
|
"""Retrieve the config data for the specified section.
|
||
|
|
|
||
|
|
Returns the data as a dictionary, or an empty dictionary if the file
|
||
|
|
doesn't exist.
|
||
|
|
|
||
|
|
When include_root is False, it will not read the root .json file,
|
||
|
|
effectively returning the default values.
|
||
|
|
"""
|
||
|
|
paths = [self.file_name(section_name)] if include_root else []
|
||
|
|
if self.read_directory:
|
||
|
|
pattern = os.path.join(self.directory(section_name), '*.json')
|
||
|
|
# These json files should be processed first so that the
|
||
|
|
# {section_name}.json take precedence.
|
||
|
|
# The idea behind this is that installing a Python package may
|
||
|
|
# put a json file somewhere in the a .d directory, while the
|
||
|
|
# .json file is probably a user configuration.
|
||
|
|
paths = sorted(glob.glob(pattern)) + paths
|
||
|
|
self.log.debug('Paths used for configuration of %s: \n\t%s', section_name, '\n\t'.join(paths))
|
||
|
|
data = {}
|
||
|
|
for path in paths:
|
||
|
|
if os.path.isfile(path):
|
||
|
|
with io.open(path, encoding='utf-8') as f:
|
||
|
|
recursive_update(data, json.load(f))
|
||
|
|
return data
|
||
|
|
|
||
|
|
def set(self, section_name, data):
|
||
|
|
"""Store the given config data.
|
||
|
|
"""
|
||
|
|
filename = self.file_name(section_name)
|
||
|
|
self.ensure_config_dir_exists()
|
||
|
|
|
||
|
|
if self.read_directory:
|
||
|
|
# we will modify data in place, so make a copy
|
||
|
|
data = copy.deepcopy(data)
|
||
|
|
defaults = self.get(section_name, include_root=False)
|
||
|
|
remove_defaults(data, defaults)
|
||
|
|
|
||
|
|
# Generate the JSON up front, since it could raise an exception,
|
||
|
|
# in order to avoid writing half-finished corrupted data to disk.
|
||
|
|
json_content = json.dumps(data, indent=2)
|
||
|
|
|
||
|
|
f = io.open(filename, 'w', encoding='utf-8')
|
||
|
|
with f:
|
||
|
|
f.write(json_content)
|
||
|
|
|
||
|
|
def update(self, section_name, new_data):
|
||
|
|
"""Modify the config section by recursively updating it with new_data.
|
||
|
|
|
||
|
|
Returns the modified config data as a dictionary.
|
||
|
|
"""
|
||
|
|
data = self.get(section_name)
|
||
|
|
recursive_update(data, new_data)
|
||
|
|
self.set(section_name, data)
|
||
|
|
return data
|