AWS Lambda Publish Messages to SNS in cross region - amazon-web-services

Question

I have a Lambda function (east-us-1) that needs to publish messages to SNS topics in both (east-us-1) & (eu-central-1) regions. Is this possible?
Here is my code snippet. Can someone help on how can I achieve this?
I am surprised to see that the boto3 client documentation says "You can publish messages only to topics and endpoints in the same Amazon Web Services Region"
Link Here:
from __future__ import print_function
import json
import urllib
import boto3
print('Loading message function...')
def send_to_sns(message, context):
# This function receives JSON input with three fields: the ARN of an SNS topic,
# a string with the subject of the message, and a string with the body of the message.
# The message is then sent to the SNS topic.
#
# Example:
# {
# "topic": "arn:aws:sns:REGION:123456789012:MySNSTopic",
# "subject": "This is the subject of the message.",
# "message": "This is the body of the message."
# }
sns = boto3.client('sns')
sns.publish(
TopicArn=message['topic'],
Subject=message['subject'],
Message=message['body']
)
return ('Sent a message to an Amazon SNS topic.')
My code throws the following error when SNS is in different region
{
"response": {
"stackTrace": [
[
"/var/task/lambda_function.py",
28,
"send_to_sns",
"Message=message['body']"
],
[
"/var/runtime/botocore/client.py",
357,
"_api_call",
"return self._make_api_call(operation_name, kwargs)"
],
[
"/var/runtime/botocore/client.py",
676,
"_make_api_call",
"raise error_class(parsed_response, operation_name)"
]
],
"errorType": "InvalidParameterException",
"errorMessage": "An error occurred (InvalidParameter) when calling the Publish operation: Invalid parameter: TopicArn"
}
}

Answer 1

you are facing this issue because of region conflict with below code you can check
your current region
my_session = boto3.session.Session()
my_region = my_session.region_name
and to solve your problem just do this i am assuming you are connected to us-east-1 and your sns is present in us-east-2 region
sns = boto3.client('sns',region_name='us-east-2')