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亚马逊的对象存储boto3访问应用实例

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【关于boto3】

Boto3是亚马逊AWS提供的python SDK，最为常用的功能是S3对象存储的访问。作为标准的S3 SDK，除了访问AWS，也可以访问其他兼容S3 API的云存储厂商。

Boto3的项目地址为：https://github.com/boto/boto3.git

Boto3的AWS doc地址为：https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/s3.html#service-resource

需要指出的是，AWS的文档说明较为混乱，现在给大家提供一个简单的使用说明和范例。

【准备】

首先需要安装python，建议使用Python 3.6及以后的版本。

通过pip安装boto3的包即可：

pip install boto3

在你的python脚本直接引用boto3即可：
	import boto3

正式使用boto3之前，你还需要具备云存储厂商的access key和secret_key。先给出一对土星云的测试key，有需要的可以去土星云存储官网注册获取。

param_endpoint=‘https://s3.local-north-1.saturncloud.com.cn:6666’

param_access_key=‘3ABC8E3ABC387442B3936F9426B11C1B’

param_secret_key=‘0428D37B0FDC14805AF0153969C272F3’

【创建client】

先初始化一个client对象，我们可以定义一个方法如下：

def setup_client(endpoint, access_key_id, secret_access_key):

return boto3.client(

‘s3’,

aws_access_key_id=access_key_id,

aws_secret_access_key=secret_access_key,

use_ssl=True,

region_name=‘cn’,

endpoint_url=endpoint,

config=Config(s3={“addressing_style”: “virtual”, “signature_version”: ‘s3v4’}))

再定义一个判断http响应状态的方法：

def is_result_ok(return_obj):

ifcode = return_obj[‘ResponseMetadata’][‘HTTPStatusCode’]

if ifcode == 200 or ifcode == 204:

return True

else:

return False

然后在main函数中调用创建client的方法：

if

name

== ‘

main

’:

print(‘Start SCS testing at ‘+datetime.datetime.now().strftime(’%Y-%m-%d %H:%M:%S’))

s3=setup_client(param_endpoint, param_access_key, param_secret_key)

【创建存储桶】

以当前时间为名创建一个存储桶：

bucket_id=datetime.datetime.now().strftime(‘test-%Y%m%d-%H%M%S’)

result=cre_bucket(s3, bucket_id)

if is_result_ok(result):
	print('bucket ['+bucket_id+'] created ok.')
else:
	print('bucket ['+bucket_id+'] created fail.')
	print(result)
	sys.exit(1)

【上传文件】

定义一个上传文件的方法如下：

def put_obj(s3, bucket_id, filename, local_dir):

return s3.put_object(Bucket=bucket_id, Body=open(local_dir+’/’+filename, ‘rb’), Key=filename)

选择一个本地文件上传到刚刚创建的存储桶

param_test_local_dir=’/tmp/’

filename=‘test.txt’

result=put_obj(s3, bucket_id, filename, param_test_local_dir)

if is_result_ok(result):

print(‘put_obj [’+filename+’] ok.’)

else:

print(‘put_obj [’+filename+’] fail.’)

print(result)

return

【下载文件】

定义一个下载文件的方法：

def get_obj(s3, bucket_id, filename):

return s3.get_object(Bucket=bucket_id, Key=filename)

我们再把刚才上传的文件下载下来

result=get_obj(s3, bucket_id, filename)

if is_result_ok(result):
	print('get_obj ['+filename+'] ok.')
else:
	print('get_obj ['+filename+'] fail.')
	print(result)
	return

【删除文件】

首先定义一个删除S3存储桶文件的方法

def del_obj(s3, bucket_id, filename):

return s3.delete_object(Bucket=bucket_id, Key=filename)

然后调用此方法即可删除刚刚上传到云端的文件：

result=del_obj(s3, bucket_id, filename)

if is_result_ok(result):
	print('del_obj ['+filename+'] ok.')
else:
	print('del_obj ['+filename+'] fail.')
	print(result)
	return

【结语】

上面已经给出了一个简单的使用范例，更多的接口和使用方法，可以查看AWS的文档和云存储厂商的文档。

【附 完整代码】

############################################################################################################

‘’’

Random test script for saturn cloud systems.

Usage:

1. Change test parameters through modifying param_XXXX in test configurations.
2. Run ‘python scs_rand_test.py’
3. For better performance, please set param_test_local_dir to a ramdisk path, such as ‘/run’ in Linux.

Requirement:

1. Python 3.6 or higher version.
2. boto3, use ‘pip install boto3 –user’ to install.

by sam 2021-10-06

‘’’

############################################################################################################

import time

import datetime

import os

import sys

import subprocess

import random

import numpy as np

import threading

from queue import Queue

import boto3

from botocore.config import Config

############################################################################################################

‘’’

Test configurations

‘’’

############################################################################################################

param_endpoint=‘https://s3.local-north-1.saturncloud.com.cn:6666’

param_access_key=‘3ABC8E3ABC387442B3936F9426B11C1B’

param_secret_key=‘0428D37B0FDC14805AF0153969C272F3’

param_test_local_dir=’/tmp/’

param_test_max_blocks=33

param_block_size=256*1024

############################################################################################################

‘’’

Common used API fuctions

‘’’

############################################################################################################

def setup_client(endpoint, access_key_id, secret_access_key):

return boto3.client(

‘s3’,

aws_access_key_id=access_key_id,

aws_secret_access_key=secret_access_key,

use_ssl=True,

region_name=‘cn’,

endpoint_url=endpoint,

config=Config(s3={“addressing_style”: “virtual”, “signature_version”: ‘s3v4’}))

def cre_bucket(s3, bucket_id):

return s3.create_bucket(Bucket=bucket_id,)

def del_bucket(s3, bucket_id):

return s3.delete_bucket(Bucket=bucket_id,)

def put_obj(s3, bucket_id, filename, local_dir):

return s3.put_object(Bucket=bucket_id, Body=open(local_dir+’/’+filename, ‘rb’), Key=filename)

def get_obj(s3, bucket_id, filename):

return s3.get_object(Bucket=bucket_id, Key=filename)

def del_obj(s3, bucket_id, filename):

return s3.delete_object(Bucket=bucket_id, Key=filename)

def is_result_ok(return_obj):

ifcode = return_obj[‘ResponseMetadata’][‘HTTPStatusCode’]

if ifcode == 200 or ifcode == 204:

return True

else:

return False

############################################################################################################

‘’’

Test applications

‘’’

############################################################################################################

def create_dummy_file(file_path):

blocks=random.randrange(0, param_test_max_blocks, 1)

last_bytes=random.randrange(1, param_block_size+1, 1)

total_size=blocks*param_block_size+last_bytes

file=open(file_path, mode='wb')
file.write(np.random.bytes(total_size))
file.close()

def test_task(bucket_id):

s3=setup_client(param_endpoint, param_access_key, param_secret_key)

filename='put_obj'
create_dummy_file(param_test_local_dir+'/'+filename)
result=put_obj(s3, bucket_id, filename, param_test_local_dir)

if is_result_ok(result):
	print('put_obj ['+filename+'] ok.')
else:
	print('put_obj ['+filename+'] fail.')
	print(result)
	return

result=get_obj(s3, bucket_id, filename)

if is_result_ok(result):
	print('get_obj ['+filename+'] ok.')
else:
	print('get_obj ['+filename+'] fail.')
	print(result)
	return

filename_new='get_obj'
file=open(param_test_local_dir+'/'+filename_new, mode='wb')
file.write(result['Body'].read())
file.close()

cmd_string='cmp '+param_test_local_dir+'/'+filename+' '+param_test_local_dir+'/'+filename_new	
cmd_result=subprocess.getoutput(cmd_string)

if len(cmd_result)>1:
	print('content error at ['+filename+'] and ['+filename_new+']')
	return

result=del_obj(s3, bucket_id, filename)

if is_result_ok(result):
	print('del_obj ['+filename+'] ok.')
else:
	print('del_obj ['+filename+'] fail.')
	print(result)
	return

cmd_string='rm '+param_test_local_dir+'/'+filename+' '+param_test_local_dir+'/'+filename_new	
os.system(cmd_string)

############################################################################################################

‘’’

Script entrance

‘’’

############################################################################################################

if

name

== ‘

main

’:

print(‘Start SCS random testing at ‘+datetime.datetime.now().strftime(’%Y-%m-%d %H:%M:%S’))

s3=setup_client(param_endpoint, param_access_key, param_secret_key)

bucket_id=datetime.datetime.now().strftime('test-%Y%m%d-%H%M%S')

result=cre_bucket(s3, bucket_id)

if is_result_ok(result):
	print('bucket ['+bucket_id+'] created ok.')
else:
	print('bucket ['+bucket_id+'] created fail.')
	print(result)
	sys.exit(1)
	pass

test_task(bucket_id)

result=del_bucket(s3, bucket_id)

if is_result_ok(result):
	print('bucket ['+bucket_id+'] deleted ok.')
else:
	print('bucket ['+bucket_id+'] deleted fail.')
	print(result)
	sys.exit(1)
	pass

print('End SCS random testing at '+datetime.datetime.now().strftime('%Y-%m-%d %H:%M:%S'))