Rewrite dungeon to encapsulate filesystem access

This commit is contained in:
Tim Van Baak 2019-06-13 22:33:43 -07:00
parent f8faa29caa
commit 6b2f898d36
2 changed files with 275 additions and 99 deletions

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@ -2,110 +2,258 @@
import os
import logging
import ast
import importlib.util
import time
import random
import traceback
# Application imports
from item import create_item
# Globals
logger = logging.getLogger("inquisitor.dungeon")
class ReadableItem():
"""
An abstraction layer around items saved in dungeon cell folders.
Provides read-only access with a deactivation function.
If the underlying item is changed, those changes may be overwritten by deactivation.
Members:
path: path to the wrapped item's file
cell: name of the cell the item is in
id: the item's id
item: the wrapped item
"""
def __init__(self, dungeon_path, cell_name, item_id):
self.path = os.path.join(dungeon_path, cell_name, item_id + ".item")
self.cell = cell_name
self.id = item_id
logger.debug("Loading '{0.id}' from '{0.cell}'".format(self))
with open(self.path, 'r', encoding='utf-8') as f:
self.item = ast.literal_eval(f.read())
def __getitem__(self, key):
return self.item[key]
def __setitem__(self, key, value):
raise TypeError("ReadableItem is not writable")
def __contains__(self, key):
return key in self.item
def __repr__(self):
return "ReadableItem({0.cell}/{0.id})".format(self)
def __str__(self):
return repr(self)
def deactivate(self):
self.item['active'] = False
logger.debug("Deactivating item at {0.path}".format(self))
with open(self.path, 'w', encoding='utf-8') as f:
f.write(str(self.item))
class DungeonCell():
"""
An abstraction layer around a folder containing items generated by an item source.
Members:
name: the cell's source's name
dungeon_path: the path to the dungeon containing this cell
path: the path to this cell
state: the source's persistent state dictionary
"""
def __init__(self, dungeon_path, name):
self.name = name
self.dungeon_path = dungeon_path
self.path = os.path.join(dungeon_path, name)
state_path = os.path.join(self.path, "state")
if not os.path.isdir(self.path):
# Initialize cell state on the disk.
logger.info("Creating folder for cell {}".format(name))
os.mkdir(self.path)
self.state = {}
with open(state_path, 'w', encoding='utf-8') as f:
f.write(str(self.state))
else:
# Load cell state from the disk.
with open(state_path, 'r', encoding='utf-8') as f:
self.state = ast.literal_eval(f.read())
def _item_path(key):
return os.path.join(self.path, key + ".item")
def __getitem__(self, key):
filepath = self._item_path(key)
if not os.path.isfile(filepath):
raise KeyError("No item '{}' in cell '{}'".format(key, self.name))
return ReadableItem(self.dungeon_path, self.name, key)
def __setitem__(self, key, value):
logger.info("Setting item {} in cell {}".format(key, self.name))
if type(value) is ReadableItem:
value = value.item
if type(value) is not dict:
raise TypeError("Can't store a '{}' as '{}': not a dict".format(type(value), key))
filepath = self._item_path(key)
with open(filepath, 'w', encoding='utf-8') as f:
f.write(str(value))
def __delitem__(self, key):
logger.info("Deleting item '{}' in cell '{}'".format(key, self.name))
filepath = self._item_path(key)
if os.path.isfile(filepath):
os.remove(filepath)
def __contains__(self, key):
for item in self:
if item == key:
return True
return False
def __iter__(self):
for filename in os.listdir(self.path):
if filename.endswith(".item"):
yield filename[:-5]
def save_state(self):
filepath = os.path.join(self.path, 'state')
with open(filepath, 'w', encoding='utf-8') as f:
f.write(str(self.state))
def update_from_source(self, source, args):
logger.info("Updating source {}".format(self.name))
# Get the ids of the existing items.
prior_item_ids = [item_id for item_id in self]
# Get the new items.
new_items = itemsource.fetch_new(state, args)
self.save_state()
new_count = del_count = 0
for item in new_items:
# Store new items unconditionally.
if item['id'] not in prior_item_ids:
new_count += 1
self[item['id']] = item
# Update extant items if active, otherwise inactive items will be
# reactivated by the overwrite.
else:
prior_item = self[item['id']]
if prior_item['active']:
self[item['id']] = item
# Remove the id from the list to track its continued presence
# in the source's queue of new items.
prior_item_ids.remove(item['id'])
# Any extant item left in the list is old. Remove any items that are
# both old and inactive.
for prior_id in prior_item_ids:
if not self[prior_id]['active']:
del_count += 1
del self[prior_id]
# Return counts
return new_count, del_count
class Dungeon():
"""
A wrapper for dealing with a collection of DungeonCell folders.
Interfaces between Inquisitor and the ReadableItems produced by its
sources.
"""
def __init__(self, path):
"""
Serves as an interface between Inquisitor and a folder of
serialized readable items.
"""
self.path = path
self.log = logging.getLogger("inquisitor.dungeon")
def load_path(self, path):
self.log.debug("Loading item from {}".format(path))
with open(path, 'r', encoding='utf-8') as f:
item = ast.literal_eval(f.read())
return item
def load_item(self, source, itemid):
item_path = os.path.join(self.path, source, itemid + ".item")
return self.load_path(item_path)
def save_item(self, item):
path = os.path.join(self.path, item['source'], item['id'] + ".item")
self.log.debug("Saving item {} to {}".format(item['id'], path))
with open(path, 'w', encoding='utf-8') as f:
f.write(str(item))
def update(self, itemsource):
"""
Fetches items from the given source, saves new active items,
and clears out old inactive items.
"""
new_items = 0
self.log.info("Updating source {}".format(itemsource.SOURCE))
# Check if the source has a folder.
source_folder = os.path.join(self.path, itemsource.SOURCE)
source_state = os.path.join(source_folder, "state")
if not os.path.isdir(source_folder):
self.log.info("Creating folder {}".format(source_folder))
os.mkdir(source_folder)
# Initialize persistent state.
with open(source_state, 'w') as f:
f.write("{}")
# Load source persistent state.
state = self.load_path(source_state)
# Any inactive items that no longer show up as new should be
# removed. Track which items to check for inactivity.
extant_items_to_check = [
filename
for filename in os.listdir(source_folder)
if filename.endswith(".item")]
# Get the new items from the source.
source_items = itemsource.fetch_new(state)
with open(source_state, 'w', encoding='utf-8') as f:
f.write(str(state))
for source_item in source_items:
file_path = os.path.join(source_folder, source_item['id'] + ".item")
if os.path.isfile(file_path):
# Still-new items are exempt from activity checks.
extant_items_to_check.remove(source_item['id'] + ".item")
item = self.load_path(file_path)
if not item['active']:
# Don't reactivate inactive items.
continue
else:
new_items += 1
# Add new items and update active ones.
self.save_item(source_item)
# Check old items for inactivity.
for extant_item_filename in extant_items_to_check:
file_path = os.path.join(source_folder, extant_item_filename)
item = self.load_path(file_path)
if not item['active']:
# Remove old inactive items.
self.log.info("Deleting {}".format(file_path))
os.remove(file_path)
return new_items
def get_active_items(self):
source_folders = os.listdir(self.path)
items = []
for source_folder_name in source_folders:
items.extend(self.get_active_items_for_folder(source_folder_name))
return items
def get_active_items_for_folder(self, source):
source_folder = os.path.join(self.path, source)
item_filenames = os.listdir(source_folder)
items = []
for item_filename in item_filenames:
if not item_filename.endswith(".item"):
# Initialize DungeonCells for each folder with a state file
self.cells = {}
for filename in os.listdir(self.path):
if not os.path.isdir(os.path.join(self.path, filename)):
continue
file_path = os.path.join(source_folder, item_filename)
item = self.load_path(file_path)
if item['active']:
items.append(item)
return items
if not os.path.isfile(os.path.join(self.path, filename, 'status')):
continue
self.cells[filename] = DungeonCell(self.path, filename)
# Ensure Inquisitor's source is present
if "inquisitor" not in self.cells:
self.cells["inquisitor"] = DungeonCell(self.path, 'inquisitor')
def deactivate_item(self, source, itemid):
item_path = os.path.join(self.path, source, itemid + ".item")
if not os.path.isfile(item_path):
self.log.error("No item found: {}".format(item_path))
def __getitem__(self, key):
return self.cells[key]
def __setitem__(self, key, value):
if type(value) is not DungeonCell:
raise TypeError("Can't store a '{}' as '{}': not a DungeonCell".format(type(value), key))
self.cells[key] = value
def __contains__(self, key):
return key in self.cells
def __iter__(self):
for name in self.cells:
yield name
def push_error_item(self, title, body=None):
logger.error(title)
item = create_item(
'inquisitor',
'{:x}'.format(random.getrandbits(16 * 4)),
title,
body="<pre>{}</pre>".format(body) if body else None)
self['inquisitor'][item['id']] = item
def try_load_source(self, sources_path, source_name):
"""
Tries to load the given source, creating a cell in the dungeon if
necessary. Returns the source and its DungeonCell if the source is
valid and None, None otherwise.
"""
# Check if the named source is present in the sources directory.
source_file_path = os.path.join(sources_path, source_name + ".py")
if not os.path.isfile(source_file_path):
msg = "Could not find source '{}'".format(source_name)
self.push_error_item(msg)
return None, None
# Try to import the source module.
try:
logger.debug("Loading module {}".format(source_file_path))
spec = importlib.util.spec_from_file_location("itemsource", source_file_path)
itemsource = importlib.util.module_from_spec(spec)
spec.loader.exec_module(itemsource)
if not hasattr(itemsource, 'fetch_new'):
raise ImportError("fetch_new missing")
except Exception:
msg = "Error importing source '{}'".format(source_name)
self.push_error_item(msg, traceback.format_exc())
return None, None
# Since the source is valid, get or create the source cell.
if source_name not in self:
self[source_name] = DungeonCell(self.path, source_name)
return itemsource, self[source_name]
def update(self, source_arg, args):
"""
Loads the given source and fetches new items. Clears old and inactive items.
"""
# Split off the source name from the fetch argument.
splits = source_arg.split(":", maxsplit=1)
source_name = splits[0]
source_args = splits[1] if len(splits) > 1 else None
# Load the source.
source, cell = self.try_load_source(args.srcdir, source_name)
if source is None or cell is None:
# try_load_source has already logged the error
return
# Update the cell from the source.
try:
new_count, deleted_count = cell.update_from_source(source, source_args)
logger.info("{} new item{}, {} deleted item{}".format(
new_count, "s" if new_count != 1 else "",
deleted_count, "s" if deleted_count != 1 else ""))
except:
msg = "Error fetching items from source '{}'".format(source_name)
self.push_error_item(msg, traceback.format_exc())
return
item = self.load_path(item_path)
item['active'] = False
self.save_item(item)
return item

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inquisitor/item.py Normal file
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# Standard library imports
import importlib.util
import os
import logging
import time
# Globals
logger = logging.getLogger("inquisitor.item")
def create_item(source, item_id, title, link=None, time=None, author=None, body=None):
item = {
'id': item_id,
'source': source,
'active': True,
'created': time.time(),
'title': title,
}
if link is not None:
item['link'] = link
if time is not None:
item['time'] = time
if author is not None:
item['author'] = author
if body is not None:
item['body'] = body
return item