分布式存储——ceph 的 python 基础接口

python 使用 boto 库完成分布式存储读、写、判断接口

import boto
import boto.s3.connection
from boto.s3.key import Key
import os


class ImageFeatIO:
    __read_singleton = None
    __write_singleton = None
    __read_count = 0
    __write_count =0

    def __init__(self):
        pass

    @staticmethod
    def get_write_instance():
        if ImageFeatIO.__write_singleton is None:
            ImageFeatIO.__write_count += 1
            print("create write instance:{0}",ImageFeatIO.__write_count)
            paras = get_config('config')
            access_key = paras['access_key']
            secret_key =paras['secret_key']
            write_host=paras['file_write_host']
            conn = boto.connect_s3(
                aws_access_key_id=access_key,
                aws_secret_access_key=secret_key,
                host=write_host, is_secure=False,
                calling_format=boto.s3.connection.OrdinaryCallingFormat()
            )
            bucket_name = paras['bucket_name']
            bucket = conn.get_bucket(bucket_name)
            ImageFeatIO.__write_singleton=bucket
        return ImageFeatIO.__write_singleton

    @staticmethod
    def get_read_instance():
        if ImageFeatIO.__read_singleton is None:
            ImageFeatIO.__read_count += 1
            print("create read instance:{0}", ImageFeatIO.__read_count)
            paras = get_config('config')
            access_key = paras['access_key']
            secret_key = paras['secret_key']
            read_host = paras['file_read_host']
            conn = boto.connect_s3(
                aws_access_key_id=access_key,
                aws_secret_access_key=secret_key,
                host=read_host, is_secure=False,
                calling_format=boto.s3.connection.OrdinaryCallingFormat()
            )
            bucket_name = paras['bucket_name']
            bucket = conn.get_bucket(bucket_name)
            ImageFeatIO.__write_singleton = bucket
        return ImageFeatIO.__read__singleton


def write_image_feature_to_file(id, imageFeaturestring):
    bucket = ImageFeatIO.get_write_instance()
    k = Key(bucket)
    k.key = id
    res = k.set_contents_from_string(imageFeaturestring)
    return res


def read_image_feature_from_file(id):
    bucket = ImageFeatIO.get_write_instance()
    k = Key(bucket)
    k.key=id
    feature = k.get_contents_as_string()
    return feature


def if_image_feature_exist(id):
    bucket = ImageFeatIO.get_write_instance()
    key = bucket.get_key(id)

    return key is not None


def get_config(config_file='config'):
    paras = dict()
    if os.path.exists(config_file):
        f = open(config_file)
        line = f.readline()
        while line:
            # print('line is ', line)
            s = line.replace(' ', '').replace('
','').split('=')
            print(s, len(s))
            paras[s[0]] = s[1]
            line = f.readline()
        # print(' paras: ', paras)
        f.close()
    else:
        raise ValueError(config_file + ': file not exsit!')
    return paras

# if __name__ == "__main__":
#     instance1 = ImageFeatIO.get_write_instance()
#     instance2 = ImageFeatIO.get_write_instance()
#     instance3 = ImageFeatIO.get_write_instance()
#
#
#     print id(instance1)
#     print id(instance2)

其中 config 文件为参数配置文件， 不同参数以回车键分割