lambdaを使ってSNSのアクセスポリシーを取得、変更、更新したいのですが、更新の部分set_topic_attributesが上手くいきません
解決方法を教えて頂きたいです。

py
1import os
2import boto3
3import json
4import ast
5
6import logging
7logger = logging.getLogger()
8logger.setLevel(logging.INFO)
9
10topic_arn = os.environ['topic_arn']
11account_no = os.environ['account_no']
12
13sns_client = boto3.client('sns')
14
15def lambda_handler(event, context):
16
17    # snsポリシー取得
18    sns_policy = get_sns_policy(sns_client, topic_arn)
19    print('sns_policy:',sns_policy)
20    
21    if sns_policy != 'policy_not_exist':
22        # ポリシーの中に'S3-Events'があるかチェック
23        check_policy_result = check_policy(sns_policy)
24        print('check_policy_result:',check_policy_result)
25
26        if not check_policy_result:
27            # snsポリシー修正
28            new_sns_policy = mod_sns_policy(sns_policy, topic_arn, account_no)
29            print('new_sns_policy:',new_sns_policy)
30            
31            # 修正したポリシーをsnsにアプデ
32            update_sns_policy(sns_client, new_sns_policy, topic_arn)
33
34
35    
36    
37def get_sns_policy(sns_client, topic_arn):
38    try:
39        response = sns_client.get_topic_attributes(TopicArn=topic_arn)
40        return ast.literal_eval(response['Attributes']['Policy'])
41    except Exception:
42        return 'policy_not_exist'
43
44    
45def check_policy(sns_policy):
46    print(type(sns_policy))
47    s3_events_flg = False
48    for statement in sns_policy['Statement']:
49        # キー"Sid"がある場合　かつ　値が "S3-Events"の場合
50        if "Sid" in statement.keys() and statement["Sid"] == "S3-Events":
51            print('S3-Events Yes it is')
52            s3_events_flg = True
53            return s3_events_flg
54        else: print('S3-Events No it isnt')
55    return s3_events_flg
56    
57    
58def mod_sns_policy(sns_policy, topic_arn, account_no):
59    print('mod_sns_policy_function')
60
61    new_statement = {
62        "Sid": "S3-Events","Effect": "Allow",
63        "Principal": {"Service": "s3.amazonaws.com"},
64        "Action": "sns:Publish",
65        "Resource": topic_arn,
66        "Condition": {"StringEquals": { "AWS:SourceAccount": account_no }}
67    }
68    sns_policy['Statement'].append(new_statement)
69    
70    return sns_policy
71
72
73def update_sns_policy(sns_client, new_sns_policy, topic_arn):
74    print('update_sns_policy_function')
75    
76    jsondumps_new_sns_policy = json.dumps(new_sns_policy)
77    str_new_sns_policy = str(new_sns_policy)
78
79    try:
80        sns_client.set_topic_attributes(
81            TopicArn=topic_arn,
82            AttributeName='DeliveryPolicy',
83            AttributeValue=str_new_sns_policy
84        )
85    except Exception as e:
86        logger.error(e)

Lambda設定

ライタイム：Python 3.9
アーキテクチャ：x86_64

試したこと

sns_client.set_topic_attributes()のAttributeValue=に入る部分を、json.dumpsやstrなどの形に変換して試してみました。

new_sns_policy (pythonのdict形式のまま)の場合

[ERROR]	2022-03-20T12:57:40.342Z	11dd47c8-2cb7-4240-a382-74a016619469	Parameter validation failed:
Invalid type for parameter AttributeValue, value: { ポリシー の中身(割愛) }, type: <class 'dict'>, valid types: <class 'str'>

json.dumps(new_sns_policy) の場合

[ERROR]	2022-03-20T12:25:00.778Z	eac745dd-e649-492d-b551-bab8bb62fcb6	An error occurred (InvalidParameter) when calling the SetTopicAttributes operation: Invalid parameter: DeliveryPolicy: Unexpected JSON member: Version

str(new_sns_policy)の場合

[ERROR]	2022-03-20T12:54:13.830Z	404be517-147f-4fe8-929a-6788049c068c	An error occurred (InvalidParameter) when calling the SetTopicAttributes operation: Invalid parameter: DeliveryPolicy: Invalid JSON: Unexpected character (''' (code 39)) at [line: 1, column: 3]: was expecting double-quote to start field name