235 lines
9.9 KiB
Python
235 lines
9.9 KiB
Python
# -*- coding: utf-8 -*-
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import json
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import os
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import sys
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import errno
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import threading
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import logging
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import uuid
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import hashlib
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import crcmod
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from .cos_comm import *
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from .streambody import StreamBody
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from .cos_threadpool import SimpleThreadPool
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logger = logging.getLogger(__name__)
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class ResumableDownLoader(object):
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def __init__(self, cos_client, bucket, key, dest_filename, object_info, part_size=20, max_thread=5,
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enable_crc=False, progress_callback=None, dump_record_dir=None, key_simplify_check=True, **kwargs):
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self.__cos_client = cos_client
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self.__bucket = bucket
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self.__key = key
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self.__dest_file_path = os.path.abspath(dest_filename)
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self.__object_info = object_info
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self.__max_thread = max_thread
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self.__enable_crc = enable_crc
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self.__progress_callback = progress_callback
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self.__headers = kwargs
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self.__key_simplify_check = key_simplify_check
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self.__max_part_count = 100 # 取决于服务端是否对并发有限制
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self.__min_part_size = 1024 * 1024 # 1M
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self.__part_size = self.__determine_part_size_internal(int(object_info['Content-Length']), part_size)
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self.__finished_parts = []
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self.__lock = threading.Lock()
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self.__record = None # 记录当前的上下文
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if not dump_record_dir:
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self.__dump_record_dir = os.path.join(os.path.expanduser('~'), '.cos_download_tmp_file')
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else:
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self.__dump_record_dir = dump_record_dir
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record_filename = self.__get_record_filename(bucket, key, self.__dest_file_path)
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self.__record_filepath = os.path.join(self.__dump_record_dir, record_filename)
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self.__tmp_file = None
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if not os.path.exists(self.__dump_record_dir):
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# 多进程并发情况下makedirs会出现冲突, 需要进行异常捕获
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try:
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os.makedirs(self.__dump_record_dir)
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except OSError as e:
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if e.errno != errno.EEXIST:
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logger.error('os makedir error: dir: {0}, errno {1}'.format(self.__dump_record_dir, e.errno))
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raise
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pass
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logger.debug('resumale downloader init finish, bucket: {0}, key: {1}'.format(bucket, key))
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def start(self):
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logger.debug('start resumable download, bucket: {0}, key: {1}'.format(self.__bucket, self.__key))
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self.__load_record() # 从record文件中恢复读取上下文
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assert self.__tmp_file
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open(self.__tmp_file, 'a').close()
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# 已完成分块先设置下载进度
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if self.__progress_callback:
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for finished_part in self.__finished_parts:
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self.__progress_callback.report(finished_part.length)
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parts_need_to_download = self.__get_parts_need_to_download()
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logger.debug('parts_need_to_download: {0}'.format(parts_need_to_download))
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pool = SimpleThreadPool(self.__max_thread)
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for part in parts_need_to_download:
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part_range = "bytes=" + str(part.start) + "-" + str(part.start + part.length - 1)
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headers = dict.copy(self.__headers)
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headers["Range"] = part_range
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pool.add_task(self.__download_part, part, headers)
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pool.wait_completion()
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result = pool.get_result()
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if not result['success_all']:
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raise CosClientError('some download_part fail after max_retry, please download_file again')
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if os.path.exists(self.__dest_file_path):
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os.remove(self.__dest_file_path)
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os.rename(self.__tmp_file, self.__dest_file_path)
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if self.__enable_crc:
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self.__check_crc()
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self.__del_record()
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logger.debug('download success, bucket: {0}, key: {1}'.format(self.__bucket, self.__key))
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def __get_record_filename(self, bucket, key, dest_file_path):
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dest_file_path_md5 = hashlib.md5(dest_file_path.encode("utf-8")).hexdigest()
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key_md5 = hashlib.md5(key.encode("utf-8")).hexdigest()
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return '{0}_{1}.{2}'.format(bucket, key_md5, dest_file_path_md5)
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def __determine_part_size_internal(self, file_size, part_size):
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real_part_size = part_size * 1024 * 1024 # MB
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if real_part_size < self.__min_part_size:
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real_part_size = self.__min_part_size
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while real_part_size * self.__max_part_count < file_size:
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real_part_size = real_part_size * 2
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logger.debug('finish to determine part size, file_size: {0}, part_size: {1}'.format(file_size, real_part_size))
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return real_part_size
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def __splite_to_parts(self):
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parts = []
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file_size = int(self.__object_info['Content-Length'])
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num_parts = int((file_size + self.__part_size - 1) / self.__part_size)
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for i in range(num_parts):
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start = i * self.__part_size
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if i == num_parts - 1:
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length = file_size - start
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else:
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length = self.__part_size
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parts.append(PartInfo(i + 1, start, length))
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return parts
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def __get_parts_need_to_download(self):
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all_set = set(self.__splite_to_parts())
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logger.debug('all_set: {0}'.format(len(all_set)))
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finished_set = set(self.__finished_parts)
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logger.debug('finished_set: {0}'.format(len(finished_set)))
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return list(all_set - finished_set)
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def __download_part(self, part, headers):
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with open(self.__tmp_file, 'rb+') as f:
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f.seek(part.start, 0)
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range = None
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traffic_limit = None
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if 'Range' in headers:
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range = headers['Range']
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if 'TrafficLimit' in headers:
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traffic_limit = headers['TrafficLimit']
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logger.debug("part_id: {0}, part_range: {1}, traffic_limit:{2}".format(part.part_id, range, traffic_limit))
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result = self.__cos_client.get_object(Bucket=self.__bucket, Key=self.__key, KeySimplifyCheck=self.__key_simplify_check, **headers)
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result["Body"].pget_stream_to_file(f, part.start, part.length)
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self.__finish_part(part)
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if self.__progress_callback:
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self.__progress_callback.report(part.length)
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def __finish_part(self, part):
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logger.debug('download part finished,bucket: {0}, key: {1}, part_id: {2}'.
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format(self.__bucket, self.__key, part.part_id))
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with self.__lock:
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self.__finished_parts.append(part)
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self.__record['parts'].append({'part_id': part.part_id, 'start': part.start, 'length': part.length})
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self.__dump_record(self.__record)
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def __dump_record(self, record):
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record_filepath = self.__record_filepath
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if os.path.exists(self.__record_filepath):
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record_filepath += '.tmp'
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with open(record_filepath, 'w') as f:
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json.dump(record, f)
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logger.debug(
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'dump record to {0}, bucket: {1}, key: {2}'.format(record_filepath, self.__bucket, self.__key))
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if record_filepath != self.__record_filepath:
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os.remove(self.__record_filepath)
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os.rename(record_filepath, self.__record_filepath)
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def __load_record(self):
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record = None
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if os.path.exists(self.__record_filepath):
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with open(self.__record_filepath, 'r') as f:
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record = json.load(f)
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ret = self.__check_record(record)
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# record记录是否跟head object的一致，不一致则删除
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if not ret:
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self.__del_record()
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record = None
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else:
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self.__part_size = record['part_size']
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self.__tmp_file = record['tmp_filename']
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if not os.path.exists(self.__tmp_file):
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record = None
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self.__tmp_file = None
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self.__del_record()
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else:
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self.__finished_parts = list(
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PartInfo(p['part_id'], p['start'], p['length']) for p in record['parts'])
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logger.debug('load record: finished parts nums: {0}'.format(len(self.__finished_parts)))
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self.__record = record
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if not record:
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self.__tmp_file = "{file_name}_{uuid}".format(file_name=self.__dest_file_path, uuid=uuid.uuid4().hex)
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record = {'bucket': self.__bucket, 'key': self.__key, 'tmp_filename': self.__tmp_file,
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'mtime': self.__object_info['Last-Modified'], 'etag': self.__object_info['ETag'],
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'file_size': self.__object_info['Content-Length'], 'part_size': self.__part_size, 'parts': []}
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self.__record = record
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self.__dump_record(record)
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def __check_record(self, record):
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return record['etag'] == self.__object_info['ETag'] and \
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record['mtime'] == self.__object_info['Last-Modified'] and \
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record['file_size'] == self.__object_info['Content-Length']
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def __del_record(self):
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os.remove(self.__record_filepath)
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logger.debug('ResumableDownLoader delete record_file, path: {0}'.format(self.__record_filepath))
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def __check_crc(self):
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logger.debug('start to check crc')
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c64 = crcmod.mkCrcFun(0x142F0E1EBA9EA3693, initCrc=0, xorOut=0xffffffffffffffff, rev=True)
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with open(self.__dest_file_path, 'rb') as f:
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local_crc64 = str(c64(f.read()))
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object_crc64 = self.__object_info['x-cos-hash-crc64ecma']
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if local_crc64 is not None and object_crc64 is not None and local_crc64 != object_crc64:
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raise CosClientError('crc of client: {0} is mismatch with cos: {1}'.format(local_crc64, object_crc64))
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class PartInfo(object):
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def __init__(self, part_id, start, length):
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self.part_id = part_id
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self.start = start
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self.length = length
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def __eq__(self, other):
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return self.__key() == other.__key()
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def __hash__(self):
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return hash(self.__key())
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def __key(self):
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return self.part_id, self.start, self.length
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