FastDFS加Redis实现自定义文件名存储海量文件

FastDFS非常适合存储大量的小文件，遗憾的是本身不支持自定义文件名，文件名是存储成功以后根据存储位置生成的一个file_id。很多应用场景不得不使用自定义文件名，在不修改其源码的情况下，可以在存储客户端fdfs_client增加一个用来存储自定义文件名和fastdfs的file_id之间的映射关系的数据库间接实现自定义文件名的存取和访问，在这里我们选用了reids。顺便说一下，淘宝也有一个类似于FastDFS的文件存储系统TFS，对于自定义文件名，它是用mysql来存储映射关系的，我认为在高并发访问下mysql本身就是瓶颈，因此在这个方案中采用了redis。

准备工作：

fastdfs环境安装...略...（官方：https://code.google.com/p/fastdfs/）

redis环境安装...略...(官方：http://redis.io/)

用python实现，因此需要安装fastdfs的python客户端(下载：https://fastdfs.googlecode.com/files/fdfs_client-py-1.2.6.tar.gz)

python的redis客户端，到https://pypi.python.org/pypi/redis下载

# -*- coding: utf-8 -*-
import setting
from fdfs_client.client import *
from fdfs_client.exceptions import *
  
from fdfs_client.connection import *
  
import redis
import time
import logging
import random
  
logging.basicConfig(format='[%(levelname)s]: %(message)s', level=logging.DEBUG)
logger = logging.getLogger(__name__)
logger.setLevel(logging.DEBUG)
  
  
class RedisError(Exception):
     def __init__(self, value):
         self.value = value
     def __str__(self):
         return repr(self.value)
  
class fastdfsClient(Fdfs_client):
    def __init__(self):
        self.tracker_pool = ConnectionPool(**setting.fdfs_tracker)
        self.timeout  = setting.fdfs_tracker['timeout']
        return None
  
    def __del__(self):
        try:
            self.pool.destroy()
            self.pool = None
        except:
            pass
  
class fastdfs(object):
    def __init__(self):
        '''
        conf_file:配置文件
        '''
        self.fdfs_client = fastdfsClient()
        self.fdfs_redis = []
        for i in setting.fdfs_redis_dbs:
            self.fdfs_redis.append(redis.Redis(host=i[0], port=i[1], db=i[2]))
  
    def store_by_buffer(self,buf,filename=None,file_ext_name = None):
        '''
        buffer存储文件
        参数：
        filename:自定义文件名，如果不指定，将远程file_id作为文件名
        file_ext_name:文件扩展名（可选），如果不指定，将根据自定义文件名智能判断
        返回值：
        {
        'group':组名,
        'file_id':不含组名的文件ID,
        'size':文件尺寸,
        'upload_time':上传时间
        }
        '''
        if filename and  random.choice(self.fdfs_redis).exists(filename):
            logger.info('File(%s) exists.'%filename)
            return   random.choice(self.fdfs_redis).hgetall(filename)
        t1 = time.time()
#        try:
        ret_dict = self.fdfs_client.upload_by_buffer(buf,file_ext_name)
#        except Exception,e:
#            logger.error('Error occurred while uploading: %s'%e.message)
#            return None
        t2 = time.time()
        logger.info('Upload file(%s) by buffer, time consume: %fs' % (filename,(t2 - t1)))
        for key in ret_dict:
            logger.debug('[+] %s : %s' % (key, ret_dict[key]))
        stored_filename = ret_dict['Remote file_id']
        stored_filename_without_group = stored_filename[stored_filename.index('/')+1:]
        if not filename:
            filename =stored_filename_without_group
        vmp = {'group':ret_dict['Group name'],'file_id':stored_filename_without_group,'size':ret_dict['Uploaded size'],'upload_time':int(time.time()*1000)}
        try:
            for i in self.fdfs_redis:
                if not i.hmset(filename,vmp):
                    raise RedisError('Save Failure')
                logger.info('Store file(%s) by buffer successful' % filename)
        except Exception,e:
            logger.error('Save info to Redis failure. rollback...')
            try:
                ret_dict = self.fdfs_client.delete_file(stored_filename)
            except Exception,e:
                logger.error('Error occurred while deleting: %s'%e.message)
            return None
        return vmp
  
    def remove(self,filename):
        '''
        删除文件,
        filename是用户自定义文件名
        return True|False
        '''
        fileinfo = random.choice(self.fdfs_redis).hgetall(filename)
        stored_filename = '%s/%s'%(fileinfo['group'],fileinfo['file_id'])
        try:
            ret_dict = self.fdfs_client.delete_file(stored_filename)
            logger.info('Remove stored file successful')
        except Exception,e:
            logger.error('Error occurred while deleting: %s'%e.message)
            return False
        for i in self.fdfs_redis:
            if not i.delete(filename):
                logger.error('Remove fileinfo in redis failure')
        logger.info('%s removed.'%filename)
        return True
  
    def download(self,filename):
        '''
        下载文件
        返回二进制
        '''
        finfo = self.getInfo(filename)
        if finfo:
            ret = self.fdfs_client.download_to_buffer('%s/%s'%(finfo['group'],finfo['file_id']))
            return ret['Content']
        else:
            logger.debug('%s is not exists'%filename)
            return None
  
    def list(self,pattern='*'):
        '''
        列出文件列表
        '''
        return random.choice(self.fdfs_redis).keys(pattern)
  
    def getInfo(self,filename):
        '''
        获得文件信息
        return:{
        'group':组名,
        'file_id':不含组名的文件ID,
        'size':文件尺寸,
        'upload_time':上传时间
        }
        '''
        return random.choice(self.fdfs_redis).hgetall(filename)

配置：

# -*- coding: utf-8 -*-
#fastdfs tracker, multiple tracker supported
fdfs_tracker = {
'host_tuple':('192.168.2.233','192.168.2.234'),
'port':22122,
'timeout':30,
'name':'Tracker Pool'
}
#fastdfs meta db, multiple redisdb supported
fdfs_redis_dbs = (
    ('192.168.2.233',6379,0),
    ('192.168.2.233',6379,1)
)