[PYTHON] Amazon SNS → AWS Lambda → Slack → AWS Chatbot to execute AWS commands

Since AWS announced that AWS commands can be executed on Slack, I checked whether it supports writing from other services instead of direct input.

https://aws.amazon.com/jp/blogs/devops/running-aws-commands-from-slack-using-aws-chatbot/

Skip preparations

Skip the settings for linking Slack and AWS Chatbot because they are on the original site.

Lambda implementation

A simple thing like this

import json
import os
import logging
import urllib.request

logger = logging.getLogger(__name__)

SLACK_URL = os.environ['SLACK_URL']

def lambda_handler(event, context):
    logger.info('Start Slack message sending.')
    message = event['Records'][0]['Sns']['Message']

    params = {
        "text": message,
        "icon_emoji": ":heavy_exclamation_mark:"
    }
    text = "payload=" + json.dumps(params)
    request = urllib.request.Request(
        SLACK_URL, 
        data = text.encode("utf-8"), 
        method="POST"
    )
    with urllib.request.urlopen(request) as response:
        response = response.read().decode("utf-8")
        return response

Since the message variable contains the message sent from SNS, it is extracted. The data from SNS stored in event is as follows.

{
  "Records": [
    {
      "EventSource": "aws:sns",
      "EventVersion": "1.0",
      "EventSubscriptionArn": "ARN contents",
      "Sns": {
        "Type": "Notification",
        "MessageId": "Message ID",
        "TopicArn": "SNS topic ARN",
        "Subject": "title",
        "Message": "Message content",
        "Timestamp": "Delivery time",
        "SignatureVersion": "1",
        "Signature": "XXX",
        "SigningCertUrl": "https://XXX",
        "MessageAttributes": {}
      }
    }
  ]
}

Settings on the SNS side

Make the following SNS settings to send information to Lambda. (Very simple, no special settings)

Try sending a message from SNS

Try publishing the following message from SNS.

<@aws> help

• `<XXX>` is the notation for sending mentions in Slack.

After a while, a message was posted to Slack, and the result of issuing the AWS command was returned.

Summary

It's easy, but I've confirmed that issuing AWS commands through AWS Chatbot can also be done by writing to Slack from other services. The possibilities of issuing Slack-> AWS Chatbot-> AWS commands have expanded again.