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March 22, 2019 15:04
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datapipe.py
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| ''' | |
| Copyright (c) <2018> <Pingcheng Zhang> | |
| Permission is hereby granted, free of charge, to any person obtaining a copy | |
| of this software and associated documentation files (the "Software"), to deal | |
| in the Software without restriction, including without limitation the rights | |
| to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
| copies of the Software, and to permit persons to whom the Software is | |
| furnished to do so, subject to the following conditions: | |
| The above copyright notice and this permission notice shall be included in all | |
| copies or substantial portions of the Software. | |
| THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
| IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
| FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
| AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
| LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
| OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
| SOFTWARE. | |
| A module to conduct IO missions in three different ways. | |
| ''' | |
| import psycopg2 | |
| import glob | |
| import pandas as pd | |
| from threading import Thread | |
| import time | |
| import os | |
| from multiprocessing import Queue, Process, cpu_count | |
| class DirFileLoader: | |
| ''' | |
| A util class to load csv files in a folder to a connected database. | |
| Paralleled IO can provide an average of 3X speed up. | |
| ''' | |
| def __init__(self, pattern=os.getcwd()): | |
| ''' | |
| Initialize DirFileLoader instance | |
| Params: | |
| pattern: path string pattern | |
| Attributes: | |
| dirs: a list of csv file directory strings | |
| dir_pool: a Queue object | |
| res_pool: a list used to collect results | |
| ''' | |
| self.dirs = glob.glob(pattern) | |
| # print(self.dirs) | |
| self.dir_pool = Queue() | |
| self.res_pool = [] | |
| self._init_pool() | |
| def _init_pool(self): | |
| ''' | |
| Initialize thread/process pool for concurrent IO tasks. | |
| ''' | |
| while not self.dir_pool.empty(): | |
| self.dir_pool.get() | |
| for d in self.dirs: | |
| self.dir_pool.put(d) | |
| # print(f'Init complete:\n {list(self.dir_pool.queue)}') | |
| def sqstart(self): | |
| ''' | |
| Sequential loading csv file in and convert to pd.DataFrame, | |
| serves as a base benchmark. | |
| Params: | |
| loc: path string, same thing as pattern param in __init__ | |
| Return: | |
| fs: a list of pd.DataFrame objects | |
| ''' | |
| print(f'========== Sequential Loading Start ==========') | |
| self._init_pool() | |
| s = time.time() | |
| self.task_io(0) | |
| t = time.time() - s | |
| print(f'Read time: {round(t//60)}min {round(t%60, 8)}sec.') | |
| def mpstart(self): | |
| ''' | |
| Mulpti-processing IO task starter. | |
| Delegate io functions wrapped by self.task_io wrapper to multiple processes. | |
| ''' | |
| print(f'\n\n========== Parallel Loading Start ==========') | |
| self._init_pool() | |
| s = time.time() | |
| process_list = [Process(target=self.task_io, args=(i,)) | |
| for i in range(cpu_count()) | |
| ] | |
| for p in process_list: | |
| p.start() | |
| for p in process_list: | |
| if p.is_alive(): | |
| p.join() | |
| print(f'========== Task end in {round(time.time() - s, 4)} sec ==========\n') | |
| def mcstart(self): | |
| ''' | |
| Mulpti-thread IO task starter. | |
| Delegate io functions wrapped by self.task_io wrapper to multiple threads. | |
| ''' | |
| print(f'\n\n========== Multi-thread Loading Start ==========') | |
| self._init_pool() | |
| s = time.time() | |
| thread_list = [Thread(target=self.task_io, args=(i,)) | |
| for i in range(len(self.dirs)) | |
| ] | |
| for t in thread_list: | |
| t.start() | |
| for t in thread_list: | |
| if t.is_alive(): | |
| t.join() | |
| print(f'========== Task end in {round(time.time() - s, 4)} sec ==========\n') | |
| def task_io(self, id: int): | |
| ''' | |
| IO task wrapper. | |
| The task conducted is one of the __operations. | |
| Params: | |
| id: task number | |
| ''' | |
| print(f'IO task[{id}] start') | |
| while not self.dir_pool.empty(): | |
| try: | |
| csvfile = self.dir_pool.get(block=True, timeout=1) | |
| # io task: | |
| # tb = self.__readcsv(csvfile) | |
| # self.res_pool.append(tb) | |
| self.__csv2db(csvfile) | |
| except Exception as e: | |
| print(f'IO task[{id}] error: {e}') | |
| print(f'IO task[{id}] ended.') | |
| # Utility functions for one kind of IO opereation | |
| def __readcsv(self, file: str) -> pd.DataFrame: | |
| ''' | |
| IO task: read in csv. | |
| Params: | |
| file: file directory get from queue | |
| Return: | |
| tb: a pandas DataFrame | |
| ''' | |
| print(f'Reading {file}...') | |
| tb = pd.read_csv(file) | |
| print(f'{file} loaded.') | |
| return tb | |
| def __csv2db(self, file: str): | |
| ''' | |
| Copy csv file into a database. | |
| Params: | |
| file: file directory get from queue | |
| ''' | |
| conn = psycopg2.connect(f'host=localhost dbname=taxi user=postgres') | |
| cur = conn.cursor() | |
| with open(file, 'r') as f: | |
| next(f) # Skip the header row | |
| try: | |
| cur.copy_from(f, 'test_table', sep=',') | |
| except Exception as e: | |
| print(f'{e}') | |
| conn.commit() | |
| if __name__ == '__main__': | |
| print(os.getcwd()) | |
| loader = DirFileLoader('F:\\NY_taxi\\test\\*.csv') | |
| loader.mcstart() | |
| # res = seq_load('F:\\NY_taxi\\test\\*.csv') | |
| # print(map(type, res)) |
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