[AWS] Detects the specified character string from the Lambda execution log and notifies slack

This time, I will introduce one of the notification methods that can be used when operating using AWS services that I often touch.

Service used

• Lambda
• CloudWatch
• Slack

Implementation flow

1. Output logs from Lambda function to CloudWatch Logs
2. Detect the specified character string from CloudWatch Logs
3. Fire the Lambda function for Slack notification triggered by the detected character string
4. Notify Slack of strings with Lambda for notification

Flow details

We will actually implement it according to the above flow.

__ Step 1 __

This time, the string "test" is output to CloudWatch Logs.

__ Step 2 __

We will use the CloudWatch Logs subscription filter (Lambda) for string detection.

__ Step 3 __

Set the Lambda function for notification, log format and filter pattern

__ Step 4 __

The environment variable "Webhook URL" is set to the slack Webhook URL you want to notify.

notifi.py

import json
import os
import urllib.request
import slackweb

def lambda_handler(event, context):
    decoded_data = zlib.decompress(
        base64.b64decode(event['awslogs']['data']),
        16+zlib.MAX_WBITS
    )
    json_data = json.loads(decoded_data) 
    print(json_data['logEvents'])
    for i in json_data['logEvents']:
        test = i['message'] #Log contents
        slack = slackweb.Slack(url=os.environ['WebhookURL'])
        slack.notify(text=test)

I confirmed that it detects the character string set earlier and notifies slack.

Summary

There are multiple notification methods other than the above, but it is easier to manage if you summarize them as concisely as possible, so I would like to make it easier and easier to simplify.