This assumes you are familar with the basic configurations needed to connect to Amazon Web Services (AWS) using Python boto3. If not, check out my article Python (Scripting) - Getting Started with Amazon Web Services (AWS) boto3.

The IAM role associated with the user attempting to publish the message will need to allow sns:Publish to the SNS topic.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "sns:Publish"
            ],
            "Resource": "arn:aws:sns:us-east-1:123456789012:mytopic"
        }
    ]
}

Here is the minimal boilerplate code without any error handling to publish a message to one of your Simple Notification Service (SNS) Topics.

#!/usr/bin/python3
import boto3

client = boto3.client('sns')
client.publish(
    TopicArn='arn:aws:sns:us-east-1:123456789012:mytopic',
    Subject='Hello',
    Message='World'
)

Here is a more practical example, with try/except/else error handling.

#!/usr/bin/python3
import boto3
import sys

try:
  client = boto3.client('sns')
except Exception as exception:
  print(exception)
  sys.exit(1)

try:
  client.publish(
    TopicArn='arn:aws:sns:us-east-1:123456789012:mytopic',
    Subject='Hello',
    Message='World'
  )
except Exception as exception:
  print(exception)

If you want to publish a JSON message, you would include MessageStructure='json' and the "default" must be the top-level JSON key.

#!/usr/bin/python3
import boto3
import json
import sys

try:
  client = boto3.client('sns')
except Exception as exception:
  print(exception)
  sys.exit(1)

payload = {"foo" : "hello", "bar": "world"}

try:
  result = client.publish(
    TopicArn='arn:aws:sns:us-east-1:123456789012:mytopic',
    Subject='Hello',
    MessageStructure='json',
    Message=json.dumps({'default': json.dumps(payload)})
  )
except Exception as exception:
  print(exception)
else:
  print(f"result = {result}")

If exceptions are raised, the "result" dictionary should contain something like this.

{
  'MessageId': '80dbc5ca-2dcb-59c3-8a8a-9ab96613dca7', 
  'ResponseMetadata': {
    'RequestId': 'de7669d5-b8f5-59ee-bc60-36a6f32d1c8a', 
    'HTTPStatusCode': 200, 
    'HTTPHeaders': {
      'x-amzn-requestid': 'de7669d5-b8f5-59ee-bc60-36a6f32d1c8a', 
      'date': 'Sun, 29 Sep 2024 12:35:36 GMT', 
      'content-type': 'text/xml', 
      'content-length': '294', 
      'connection': 'keep-alive'
      },
    'RetryAttempts': 0
  }
}