python - 使用 Python Paramiko 的 SFTP 到 S3 AWS Lambda 非常慢

问题描述

我正在使用 Paramiko 库将数据从 SFTP 流式传输到 AWS 中带有 python 3.8 lambda 的 S3 存储桶。该脚本是标准的，下载小于 6MB 的整个文件，而对于较大的文件，则使用大约 6 MB 的块大小进行多块上传。但是，但我注意到速度非常慢，大约 200KB/sec 约 47MB 文件，基于在线这应该至少是 2MB/sec（这仍然被认为是相当慢）。不会有很多超过 1GB 的文件，但 15 分钟的 lambda 超时将以这个速率达到 200MB 的文件。我正在使用 VPC，但我不熟悉配置，我们有一个团队可以使用它。这有什么原因如此令人难以置信的慢吗？

脚本：

    def open_ftp_connection(self): 
      """
      Opens ftp connection and returns connection object
      """
      client = paramiko.SSHClient()
      client.load_system_host_keys() 
      try: 
        transport = paramiko.Transport(self.host_name,22) 
        #self.trans = paramiko.Transport((hostname, port))
        transport.window_size = 134217727
        transport.use_compression()

        print("A")
      except Exception as e: 
        return 'conn_error' 
      try: 
        transport.connect(username=self.ftp_username, password=self.ftp_password)
        print("B")
        #transport.exec_command("ls")
        print("C")
        
      except Exception as identifier: 
        return 'auth_error' 
      ftp_connection = paramiko.SFTPClient.from_transport(transport) 
      print("D")
      return ftp_connection        
    def transfer_chunk_from_ftp_to_s3(self,ftp_file,s3_connection,multipart_upload,bucket_name,ftp_file_path,s3_file_path, part_number,chunk_size):
        start_time = time.time()
        chunk = ftp_file.read(int(chunk_size))
        part = s3_connection.upload_part(Bucket=bucket_name,
            Key=s3_file_path, PartNumber=part_number, UploadId=multipart_upload["UploadId"],Body=chunk)
        end_time = time.time()
        total_seconds = end_time - start_time
        print(
            "speed is {} kb/s total seconds taken {}".format(
                math.ceil((int(chunk_size) / 1024) / total_seconds), total_seconds
            )
        )
        part_output = {"PartNumber": part_number, "ETag": part["ETag"]}
        return part_output
    

    def transfer_file_from_ftp_to_s3(self,
        bucket_name, ftp_file_path, s3_file_path, ftp_username, ftp_password, chunk_size,ftp_connection):
      #  ftp_connection = self.open_ftp_connection(
       #     FTP_HOST, ftp_username, ftp_password
      #  )
        ftp_file = ftp_connection.file(ftp_file_path, "r")
        s3_connection = boto3.client("s3")
        ftp_file_size = ftp_file._get_size()
        try:
            s3_file = s3_connection.head_object(Bucket=bucket_name, Key=s3_file_path)
            if s3_file["ContentLength"] == ftp_file_size:
                print("File Already Exists in S3 bucket")
                ftp_file.close()
                return
        except Exception as e:
            pass
        logger.info("file size: "+str(ftp_file_size))
        logger.info("chunk size: "+str(chunk_size))
        if ftp_file_size <= int(chunk_size):
            # upload file in one go
            print("Transferring complete File from FTP to S3...")
            ftp_file_data = ftp_file.read()
            ftp_file_data_bytes = io.BytesIO(ftp_file_data)
            s3_connection.upload_fileobj(ftp_file_data_bytes, bucket_name, s3_file_path)
            
            print("Successfully Transferred file from FTP to S3!")
            ftp_file.close()
    
        else:
            print("Transferring File from FTP to S3 in chunks...")
            # upload file in chunks
            chunk_count = int(math.ceil(ftp_file_size / float(chunk_size)))
            multipart_upload = s3_connection.create_multipart_upload(
                Bucket=bucket_name, Key=s3_file_path
            )
            logger.info("chunk count: "+str(chunk_count))
            parts = []
            for i in range(chunk_count):
                print("Transferring chunk {}...".format(i + 1))
                part = self.transfer_chunk_from_ftp_to_s3(
                    ftp_file,
                    s3_connection,
                    multipart_upload,
                    bucket_name,
                    ftp_file_path,
                    s3_file_path,
                    i + 1,
                    chunk_size
                )
                parts.append(part)
                print("Chunk {} Transferred Successfully!".format(i + 1))
    
            part_info = {"Parts": parts}
            s3_connection.complete_multipart_upload(
                Bucket=bucket_name,
                Key=s3_file_path,
                UploadId=multipart_upload["UploadId"],
                MultipartUpload=part_info,
            )
            print("All chunks Transferred to S3 bucket! File Transfer successful!")
            ftp_file.close()

上面的代码都是这样调用的：

self.transfer_file_from_ftp_to_s3(self.s3_bucket,self.ftp_full_file_path, s3_file_path, self.ftp_username, self.ftp_password, CHUNK_SIZE,ftp_connection)

这是输出：

speed is 222 kb/s total seconds taken 27.759796857833862
Chunk 1 Transferred Successfully!
Transferring chunk 2...
speed is 214 kb/s total seconds taken 28.721262216567993
Chunk 2 Transferred Successfully!
Transferring chunk 3...
speed is 193 kb/s total seconds taken 31.968283653259277
Chunk 3 Transferred Successfully!
Transferring chunk 4...
speed is 196 kb/s total seconds taken 31.360466480255127
Chunk 4 Transferred Successfully!
Transferring chunk 5...
speed is 216 kb/s total seconds taken 28.545111417770386
Chunk 5 Transferred Successfully!
Transferring chunk 6...
speed is 218 kb/s total seconds taken 28.293278217315674
Chunk 6 Transferred Successfully!
Transferring chunk 7...
speed is 217 kb/s total seconds taken 28.43106746673584
Chunk 7 Transferred Successfully!
Transferring chunk 8...
speed is 200 kb/s total seconds taken 30.775285482406616
Chunk 8 Transferred Successfully!
All chunks Transferred to S3 bucket! File Transfer successful!

编辑：

在 transfer_file_to_S3 函数中添加 ftp_file.prefetch() 似乎可以将 ~47MB 文件的速度从每秒 202KB 显着提高到 2MB。但是，对于使用相同块大小的 1GB 文件，它开始时每秒使用 2MB，但到块 10 时，速度会降低到每秒 202KB。

标签： pythonamazon-web-servicesamazon-s3aws-lambdaparamiko

python - 使用 Python Paramiko 的 SFTP 到 S3 AWS Lambda 非常慢

问题描述

解决方案

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