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85 lines
2.7 KiB
85 lines
2.7 KiB
from services.server_service import ServerMessage, ServerService |
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import json |
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import asyncio |
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""" |
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This is how you can save a file: |
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async def test_file_save(): |
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async with data_service.open('filename') as f: |
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print('write content') |
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await f.write('test string') |
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async with data_service.open('filename') as f: |
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content = await f.load() |
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print(content) |
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print('test file ok') |
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""" |
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LOCK_WAIT_SLEEP_TIMESPAN = 100 # mc |
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class FileDescriptor: |
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def __init__(self, filename: str, data_service): |
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self.filename = filename |
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self.data_service = data_service |
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async def write(self, content: str): |
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await self.data_service.save_file_content(self, content) |
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async def load(self) -> str: |
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return await self.data_service.load_file_content(self) |
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async def __aenter__(self): |
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await self.data_service.wait_and_lock(self) |
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return self |
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async def __aexit__(self, *exc): |
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await self.data_service.unlock(self) |
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class DataService: |
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def __init__(self, server_service: ServerService): |
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"""Creates fs over network via server_service""" |
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self.server_service = server_service |
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self.locks = set() |
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def open(self, filename: str) -> FileDescriptor: |
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return FileDescriptor(filename, self) |
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async def wait_and_lock(self, file_descriptor: FileDescriptor): |
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filename = file_descriptor.filename |
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while True: |
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if filename in self.locks: |
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asyncio.sleep(LOCK_WAIT_SLEEP_TIMESPAN) |
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continue |
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else: |
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self.locks.add(filename) |
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break |
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async def unlock(self, file_descriptor: FileDescriptor): |
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filename = file_descriptor.filename |
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self.locks.remove(filename) |
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async def save_file_content(self, file_descriptor: FileDescriptor, content: str): |
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""" Saves json - serializable obj with file_descriptor.filename """ |
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self.__check_lock(file_descriptor) |
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message_payload = { |
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'filename': file_descriptor.filename, |
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'content': content |
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} |
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message = ServerMessage('FILE_SAVE', message_payload) |
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await self.server_service.send_request_to_server(message) |
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async def load_file_content(self, file_descriptor: FileDescriptor) -> str: |
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self.__check_lock(file_descriptor) |
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message_payload = { 'filename': file_descriptor.filename } |
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message = ServerMessage('FILE_LOAD', message_payload) |
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return await self.server_service.send_request_to_server(message) |
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def __check_lock(self, file_descriptor: FileDescriptor): |
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filename = file_descriptor.filename |
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if filename not in self.locks: |
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raise RuntimeError('No lock for file %s' % filename)
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