AWS：Boto3：AssumeRole示例，其中包括角色使用情况

Question

我试图以这样一种方式使用AssumeRole，即我遍历多个帐户并检索这些帐户的资产。我已经做到了这一点：

import boto3
stsclient = boto3.client('sts')

assumedRoleObject = sts_client.assume_role(
RoleArn="arn:aws:iam::account-of-role-to-assume:role/name-of-role",
RoleSessionName="AssumeRoleSession1")

太好了，我有assumeRoleObject。但现在我想用它来列出像ELB这样的东西或者不是内置低级资源的东西。

怎么去做呢？如果我可能会问 - 请编写一个完整的例子，以便每个人都能从中受益。

Answer 1

要获得具有假定角色的会话：

import botocore
import boto3
import datetime
from dateutil.tz import tzlocal

assume_role_cache: dict = {}
def assumed_role_session(role_arn: str, base_session: botocore.session.Session = None):
    base_session = base_session or boto3.session.Session()._session
    fetcher = botocore.credentials.AssumeRoleCredentialFetcher(
        client_creator = base_session.create_client,
        source_credentials = base_session.get_credentials(),
        role_arn = role_arn,
        extra_args = {
        #    'RoleSessionName': None # set this if you want something non-default
        }
    )
    creds = botocore.credentials.DeferredRefreshableCredentials(
        method = 'assume-role',
        refresh_using = fetcher.fetch_credentials,
        time_fetcher = lambda: datetime.datetime.now(tzlocal())
    )
    botocore_session = botocore.session.Session()
    botocore_session._credentials = creds
    return boto3.Session(botocore_session = botocore_session)

# usage:
session = assumed_role_session('arn:aws:iam::ACCOUNTID:role/ROLE_NAME')
ec2 = session.client('ec2') # ... etc.

生成的会话凭据将在需要时自动刷新，这非常好。

注意：我之前的回答是完全错误的，但是我无法将其删除，所以我用更好的工作答案取而代之。

Answer 2

您可以使用STS令牌承担角色，例如：

class Boto3STSService(object):
def __init__(self, arn):
    sess = Session(aws_access_key_id=ARN_ACCESS_KEY,
                   aws_secret_access_key=ARN_SECRET_KEY)
    sts_connection = sess.client('sts')
    assume_role_object = sts_connection.assume_role(RoleArn=arn, RoleSessionName=ARN_ROLE_SESSION_NAME,DurationSeconds=3600)
    self.credentials = assume_role_object['Credentials']

这将为您提供临时访问密钥和密钥，以及会话令牌。使用这些临时凭证，您可以访问任何服务。例如，如果要访问ELB，可以使用以下代码：

self.tmp_credentials = Boto3STSService(arn).credentials

def get_boto3_session(self):
        tmp_access_key = self.tmp_credentials['AccessKeyId']
        tmp_secret_key = self.tmp_credentials['SecretAccessKey']
        security_token = self.tmp_credentials['SessionToken']

    boto3_session = Session(
        aws_access_key_id=tmp_access_key,
        aws_secret_access_key=tmp_secret_key, aws_session_token=security_token
    )
    return boto3_session
def get_elb_boto3_connection(self, region):
    sess = self.get_boto3_session()
    elb_conn = sess.client(service_name='elb', region_name=region)
    return elb_conn

Answer 3

如果你想要一个功能实现，这就是我所确定的：

def filter_none_values(kwargs: dict) -> dict:
    """Returns a new dictionary excluding items where value was None"""
    return {k: v for k, v in kwargs.items() if v is not None}


def assume_session(
    role_session_name: str,
    role_arn: str,
    duration_seconds: Union[int, None] = None,
    region_name: Union[str, None] = None,
) -> boto3.Session:
    """
    Returns a session with the given name and role.
    If not specified, duration will be set by AWS, probably at 1 hour.
    If not specified, region will be left unset.
    Region can be overridden by each client or resource spawned from this session.
    """
    assume_role_kwargs = filter_none_values(
        {
            "RoleSessionName": role_session_name,
            "RoleArn": role_arn,
            "DurationSeconds": duration_seconds,
        }
    )
    credentials = boto3.client("sts").assume_role(**assume_role_kwargs)["Credentials"]
    create_session_kwargs = filter_none_values(
        {
            "aws_access_key_id": credentials["AccessKeyId"],
            "aws_secret_access_key": credentials["SecretAccessKey"],
            "aws_session_token": credentials["SessionToken"],
            "region_name": region_name,
        }
    )
    return boto3.Session(**create_session_kwargs)


def main() -> None:
    session = assume_session(
        "MyCustomSessionName",
        "arn:aws:iam::XXXXXXXXXXXX:role/TheRoleIWantToAssume",
        region_name="us-east-1",
    )
    client = session.client(service_name="ec2")
    print(client.describe_key_pairs())

Answer 4

这是official AWS documentation的代码片段，其中创建了s3资源，用于列出所有s3存储桶。 boto3资源或其他服务的客户可以以类似的方式建造。

# create an STS client object that represents a live connection to the 
# STS service
sts_client = boto3.client('sts')

# Call the assume_role method of the STSConnection object and pass the role
# ARN and a role session name.
assumed_role_object=sts_client.assume_role(
    RoleArn="arn:aws:iam::account-of-role-to-assume:role/name-of-role",
    RoleSessionName="AssumeRoleSession1"
)

# From the response that contains the assumed role, get the temporary 
# credentials that can be used to make subsequent API calls
credentials=assumed_role_object['Credentials']

# Use the temporary credentials that AssumeRole returns to make a 
# connection to Amazon S3  
s3_resource=boto3.resource(
    's3',
    aws_access_key_id=credentials['AccessKeyId'],
    aws_secret_access_key=credentials['SecretAccessKey'],
    aws_session_token=credentials['SessionToken'],
)

# Use the Amazon S3 resource object that is now configured with the 
# credentials to access your S3 buckets. 
for bucket in s3_resource.buckets.all():
    print(bucket.name)