John Ajera

Posted on Mar 6

How to Send Notifications to Slack Using Python

#python #slack #automation #sqs

📢 How to Send Notifications to Slack Using Python

🚀 Introduction

If you need to send automated notifications to Slack from different services, you can use Python and Slack Incoming Webhooks to achieve this. This guide provides a generic Python script that can be used for various use cases, such as:

✅ Sending notifications from AWS Lambda.
✅ Integrating with message queues like AWS SQS.
✅ Triggering alerts from any Python application.

🔧 Step 1: Create a Slack Channel

1️⃣ Open Slack and navigate to your workspace.

2️⃣ Click on the “+” (Add a Channel) button in the sidebar.

3️⃣ Select “Create a New Channel” from the options.

4️⃣ Enter a name for your channel (e.g., #aws-notifications).

5️⃣ Choose whether the channel should be public (accessible by all workspace members) or private (invite-only).

6️⃣ Click Create to finalize the channel setup and invite relevant team members if needed.

🔧 Step 2: Create and Configure a Slack App

1️⃣ Go to Slack API Console

Open Slack API Console.

2️⃣ Click "Create an App"

Choose "From scratch".
Name it (e.g., aws-notifications).
Choose a Slack workspace.

3️⃣ Enable Incoming Webhooks

Inside your app's settings, navigate to "Incoming Webhooks".
Toggle the switch to Activate Incoming Webhooks.
Click "Add New Webhook to Workspace".
Select the newly created Slack channel (e.g., #aws-notifications).
Click Create App.

4️⃣ Generate a Webhook URL

Click "Add New Webhook to Workspace".
Select the #aws-notifications channel.
Click "Allow" to grant the necessary permissions.
Copy the generated Webhook URL. Example:

   https://hooks.slack.com/services/T00000000/B00000000/XXXXXXXXXXXXXXXXXXXXXXXX

📌 You'll use this Webhook URL in your Python script to send messages to Slack.

🔧 Step 3: Write the Python Script

This Python script sends messages to Slack. It works in AWS Lambda, local applications, or any automation tool.

import json
import urllib.request
import os

def send_slack_notification(message):
    slack_webhook_url = os.getenv("SLACK_WEBHOOK_URL")
    if not slack_webhook_url:
        raise ValueError("SLACK_WEBHOOK_URL environment variable is missing")

    data = json.dumps({"text": message}).encode("utf-8")
    req = urllib.request.Request(slack_webhook_url, data=data, headers={"Content-Type": "application/json"})

    try:
        with urllib.request.urlopen(req) as response:
            print("✅ Slack notification sent successfully!")
            return response.status
    except Exception as e:
        print(f"Failed to send message to Slack: {e}")
        return None

if __name__ == "__main__":
    message = "Hello from aws-notifications! 🚀"
    send_slack_notification(message)

🎯 Use Cases

✅ AWS Lambda Integration

Modify the script to accept event data in Lambda:

def lambda_handler(event, context):
    for record in event.get("Records", []):
        message_body = record.get("body", "No message body")
        send_slack_notification(f"AWS Lambda received: {message_body}")
    return {"status": "success"}

✅ Sending Slack Notifications from AWS SQS

AWS Lambda can trigger the script when an SQS message arrives.

✅ Sending Alerts from a Python Script

Use the script in any Python application to notify Slack:

send_slack_notification("AWS Lambda received: AWS Event Triggered")

🔧 Step 4: Sample Execution

✅ Running Locally

If running on your local machine, export your Slack webhook URL and execute the script:

export SLACK_WEBHOOK_URL=https://hooks.slack.com/services/T00000000/B00000000/XXXXXXXXXXXXXXXXXXXXXXXX
python script.py

Expected Output:

✅ Slack notification sent successfully!

✅ Running in AWS Lambda

Deploy the function and invoke it via AWS CLI:

aws lambda invoke \
  --function-name aws-notifications-lambda \
  --payload '{"Records": [{"body": "AWS Event Triggered"}]}' \
  response.json

Expected Slack Message:

AWS Lambda received: AWS Event Triggered

✅ Running via AWS SQS

Send a test message to SQS:

aws sqs send-message \
  --queue-url https://sqs.YOUR-REGION.amazonaws.com/YOUR-ACCOUNT-ID/YOUR-QUEUE \
  --message-body '{"event": "EC2 tag modified"}'

Slack will receive:

AWS Lambda received: EC2 tag modified

✅ Conclusion

Now, you have a generic Python script to send messages to Slack! 🎉 You’ve learned:

How to create a Slack channel.
How to configure Slack Webhooks.
How to send messages using Python.
How to integrate it into AWS Lambda, SQS, or any Python application.
How to execute and test the script locally and in AWS.