python - 捕获 boto3 ClientError 子类

Question

使用如下代码片段，我们可以捕获 AWS 异常:

from aws_utils import make_session

session = make_session()
cf = session.resource("iam")
role = cf.Role("foo")
try:
    role.load()
except Exception as e:
    print(type(e))
    raise e

返回的错误类型为 botocore.errorfactory.NoSuchEntityException。但是，当我尝试导入此异常时，我得到了:

>>> import botocore.errorfactory.NoSuchEntityException
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: No module named NoSuchEntityException

我能找到的捕获此特定错误的最佳方法是:

from botocore.exceptions import ClientError
session = make_session()
cf = session.resource("iam")
role = cf.Role("foo")
try:
    role.load()
except ClientError as e:
    if e.response["Error"]["Code"] == "NoSuchEntity":
        # ignore the target exception
        pass
    else:
        # this is not the exception we are looking for
        raise e

但这看起来很“hackish”。有没有办法在boto3中直接导入并捕获ClientError的特定子类？

编辑:请注意，如果您以第二种方式捕获错误并打印类型，它将是 ClientError。

Answer 1

如果您使用的是 client你可以像这样捕获异常:

import boto3

def exists(role_name):
    client = boto3.client('iam')
    try:
        client.get_role(RoleName='foo')
        return True
    except client.exceptions.NoSuchEntityException:
        return False