Setup advanced Airflow alerting with Slack integration and custom notification rules

Verify Airflow installation

Check your current Airflow version and ensure the webserver is running.

airflow version
sudo systemctl status airflow-webserver
sudo systemctl status airflow-scheduler

Install Slack provider package

Install the official Airflow Slack provider to enable webhook and API integrations.

pip install apache-airflow-providers-slack==8.6.0
airflow db upgrade

Create Slack application

Navigate to api.slack.com/apps and create a new Slack app for your workspace. This app will handle incoming webhooks and API calls from Airflow.

In your Slack app configuration:

• Enable "Incoming Webhooks" under Features
• Click "Add New Webhook to Workspace"
• Select the channel for Airflow alerts (e.g., #data-ops)
• Copy the webhook URL (starts with https://hooks.slack.com/services/)

Configure OAuth permissions

For advanced features like user mentions and channel management, add OAuth scopes to your Slack app.

Under "OAuth & Permissions", add these Bot Token Scopes:

• chat:write - Send messages as the bot
• chat:write.public - Send messages to channels the bot isn't in
• users:read - Look up user information for mentions
• channels:read - Access channel information

Install the app to your workspace and copy the "Bot User OAuth Token" (starts with xoxb-).

Test webhook connectivity

Verify the webhook works before integrating with Airflow.

curl -X POST -H 'Content-type: application/json' \
  --data '{"text":"Airflow webhook test from $(hostname)"}' \
  https://hooks.slack.com/services/YOUR/WEBHOOK/PATH

Create Slack webhook connection

Add the Slack webhook as an Airflow connection through the web UI or CLI. This connection will be referenced in your DAG alert configurations.

airflow connections add slack_webhook \
  --conn-type http \
  --conn-host https://hooks.slack.com \
  --conn-password /services/YOUR/WEBHOOK/PATH

Create Slack API connection

For advanced messaging features, create a separate connection using the OAuth token.

airflow connections add slack_api \
  --conn-type slack \
  --conn-password xoxb-YOUR-BOT-TOKEN

Configure environment variables

Set environment variables for common Slack channels and users that your notification rules will reference.

AIRFLOW_SLACK_ALERTS_CHANNEL=#data-ops
AIRFLOW_SLACK_CRITICAL_CHANNEL=#incidents
AIRFLOW_SLACK_DEV_CHANNEL=#data-dev
AIRFLOW_ON_CALL_USER=@jane.doe

Reload the environment variables:

source /etc/environment
sudo systemctl restart airflow-webserver airflow-scheduler

Create notification utility module

Create a reusable module for Slack notifications that can be imported across DAGs.

import os
from datetime import datetime
from airflow.providers.slack.operators.slack_webhook import SlackWebhookOperator
from airflow.providers.slack.operators.slack import SlackAPIPostOperator
from airflow.configuration import conf

def get_slack_channel(context):
    """Route alerts to appropriate Slack channel based on DAG tags and environment"""
    dag = context['dag']
    env = dag.tags.get('env', 'dev') if hasattr(dag, 'tags') else 'dev'
    
    if 'critical' in dag.tags:
        return os.environ.get('AIRFLOW_SLACK_CRITICAL_CHANNEL', '#incidents')
    elif env == 'prod':
        return os.environ.get('AIRFLOW_SLACK_ALERTS_CHANNEL', '#data-ops')
    else:
        return os.environ.get('AIRFLOW_SLACK_DEV_CHANNEL', '#data-dev')

def format_failure_message(context):
    """Generate rich failure message with context and actionable information"""
    task_instance = context['task_instance']
    dag = context['dag']
    execution_date = context['execution_date']
    
    webserver_url = conf.get('webserver', 'base_url', fallback='http://localhost:8080')
    log_url = f"{webserver_url}/log?dag_id={dag.dag_id}&task_id={task_instance.task_id}&execution_date={execution_date}"
    
    message = {
        "blocks": [
            {
                "type": "header",
                "text": {
                    "type": "plain_text",
                    "text": f"🚨 Airflow Task Failed: {task_instance.task_id}"
                }
            },
            {
                "type": "section",
                "fields": [
                    {"type": "mrkdwn", "text": f"*DAG:* {dag.dag_id}"},
                    {"type": "mrkdwn", "text": f"*Task:* {task_instance.task_id}"},
                    {"type": "mrkdwn", "text": f"*Execution Date:* {execution_date}"},
                    {"type": "mrkdwn", "text": f"*Try:* {task_instance.try_number}/{task_instance.max_tries}"}
                ]
            },
            {
                "type": "section",
                "text": {
                    "type": "mrkdwn",
                    "text": f"*Error:* ```{str(context.get('exception', 'Unknown error'))[:500]}```"
                }
            },
            {
                "type": "actions",
                "elements": [
                    {
                        "type": "button",
                        "text": {"type": "plain_text", "text": "View Logs"},
                        "url": log_url,
                        "style": "primary"
                    },
                    {
                        "type": "button",
                        "text": {"type": "plain_text", "text": "View DAG"},
                        "url": f"{webserver_url}/tree?dag_id={dag.dag_id}"
                    }
                ]
            }
        ]
    }
    
    return message

def create_failure_task(task_id="slack_failure_alert", **kwargs):
    """Create a Slack notification task for failure alerts"""
    return SlackWebhookOperator(
        task_id=task_id,
        http_conn_id="slack_webhook",
        message="{{ ti.xcom_pull(task_ids='format_message') }}",
        **kwargs
    )

Create DAG failure callback

Implement a callback function that triggers on DAG failures with intelligent routing logic.

import os
from airflow.providers.slack.hooks.slack_webhook import SlackWebhookHook
from .slack_notifications import get_slack_channel, format_failure_message

def task_failure_alert(context):
    """Send Slack alert when any task fails"""
    slack_webhook = SlackWebhookHook(
        http_conn_id="slack_webhook",
        webhook_token=None
    )
    
    channel = get_slack_channel(context)
    message = format_failure_message(context)
    
    # Add mention for critical failures
    if 'critical' in context['dag'].tags:
        on_call_user = os.environ.get('AIRFLOW_ON_CALL_USER', '')
        if on_call_user:
            message['blocks'].insert(1, {
                "type": "section",
                "text": {
                    "type": "mrkdwn",
                    "text": f":rotating_light: Critical failure - {on_call_user} please investigate"
                }
            })
    
    slack_webhook.send_dict(message, channel=channel)

def dag_success_alert(context):
    """Send success notification for critical DAGs"""
    dag = context['dag']
    
    # Only send success alerts for critical or production DAGs
    if not ('critical' in dag.tags or 'prod' in dag.tags):
        return
    
    slack_webhook = SlackWebhookHook(http_conn_id="slack_webhook")
    
    message = {
        "text": f":white_check_mark: DAG {dag.dag_id} completed successfully",
        "blocks": [
            {
                "type": "section",
                "text": {
                    "type": "mrkdwn",
                    "text": f":white_check_mark: *{dag.dag_id}* completed successfully at {context['execution_date']}"
                }
            }
        ]
    }
    
    channel = get_slack_channel(context)
    slack_webhook.send_dict(message, channel=channel)

Apply callbacks to existing DAGs

Modify your DAGs to use the new notification system with appropriate tags and callbacks.

from datetime import datetime, timedelta
from airflow import DAG
from airflow.operators.python_operator import PythonOperator
from utils.callbacks import task_failure_alert, dag_success_alert

default_args = {
    'owner': 'data-team',
    'depends_on_past': False,
    'start_date': datetime(2024, 1, 1),
    'email_on_failure': False,  # Disable email, use Slack instead
    'email_on_retry': False,
    'retries': 2,
    'retry_delay': timedelta(minutes=5),
    'on_failure_callback': task_failure_alert,
}

dag = DAG(
    'customer_data_etl',
    default_args=default_args,
    description='Extract and transform customer data',
    schedule_interval=timedelta(hours=6),
    catchup=False,
    tags=['prod', 'critical', 'customer-facing'],  # Tags control notification routing
    on_success_callback=dag_success_alert,
    on_failure_callback=task_failure_alert,
)

# Your existing tasks here
def extract_data(**context):
    # Simulate potential failure for testing
    if datetime.now().hour == 14:  # Fail at 2 PM for testing
        raise Exception("Database connection timeout during peak hours")
    return "data extracted"

extract_task = PythonOperator(
    task_id='extract_customer_data',
    python_callable=extract_data,
    dag=dag,
)

Create notification configuration file

Define notification rules in a configuration file for easy management across environments.

notification_rules:
  channels:
    critical: "#incidents"
    prod: "#data-ops"
    dev: "#data-dev"
    default: "#airflow-alerts"
  
  escalation:
    critical:
      immediate: ["@jane.doe", "@john.smith"]
      after_retry: ["@data-team-lead"]
    prod:
      after_failure: ["@data-team"]
  
  dag_patterns:
    customer_*:
      priority: critical
      channel: "#incidents"
      mentions: ["@customer-success"]
    
    reporting_*:
      priority: high
      channel: "#data-ops"
      business_hours_only: true
    
    test_*:
      priority: low
      channel: "#data-dev"
      suppress_retries: true

suppress_notifications:
  - dag_pattern: "test_*"
    time_range: "22:00-06:00"  # Suppress overnight test failures
  - dag_pattern: "*_backfill"
    always: true  # Never alert on backfill DAGs

Implement advanced notification logic

Create an enhanced notification system that reads the configuration file and applies complex rules.

import yaml
import re
from datetime import datetime, time
from airflow.providers.slack.hooks.slack_webhook import SlackWebhookHook

class AirflowNotificationManager:
    def __init__(self, config_path='/opt/airflow/config/notification_rules.yaml'):
        with open(config_path, 'r') as f:
            self.config = yaml.safe_load(f)
    
    def should_suppress_notification(self, context):
        """Check if notification should be suppressed based on rules"""
        dag = context['dag']
        current_time = datetime.now().time()
        
        for rule in self.config.get('suppress_notifications', []):
            # Check DAG pattern match
            if 'dag_pattern' in rule:
                pattern = rule['dag_pattern'].replace('*', '.*')
                if re.match(pattern, dag.dag_id):
                    # Always suppress
                    if rule.get('always', False):
                        return True
                    
                    # Time-based suppression
                    if 'time_range' in rule:
                        start_time, end_time = rule['time_range'].split('-')
                        start = datetime.strptime(start_time, '%H:%M').time()
                        end = datetime.strptime(end_time, '%H:%M').time()
                        
                        if start <= end:  # Same day range
                            if start <= current_time <= end:
                                return True
                        else:  # Overnight range
                            if current_time >= start or current_time <= end:
                                return True
        
        return False
    
    def get_notification_config(self, context):
        """Get notification configuration for a specific DAG"""
        dag = context['dag']
        
        # Check for specific DAG pattern matches
        for pattern, config in self.config.get('dag_patterns', {}).items():
            regex_pattern = pattern.replace('*', '.*')
            if re.match(regex_pattern, dag.dag_id):
                return config
        
        # Return default configuration
        return {
            'priority': 'normal',
            'channel': self.config['notification_rules']['channels']['default']
        }
    
    def send_enhanced_notification(self, context, notification_type='failure'):
        """Send notification with advanced logic and formatting"""
        if self.should_suppress_notification(context):
            return
        
        config = self.get_notification_config(context)
        
        slack_webhook = SlackWebhookHook(http_conn_id="slack_webhook")
        
        # Build enhanced message
        message = self.build_notification_message(context, config, notification_type)
        
        # Send to appropriate channel
        channel = config.get('channel', self.config['notification_rules']['channels']['default'])
        slack_webhook.send_dict(message, channel=channel)
    
    def build_notification_message(self, context, config, notification_type):
        """Build rich notification message with context"""
        task_instance = context['task_instance']
        dag = context['dag']
        priority = config.get('priority', 'normal')
        
        # Priority-based emoji and styling
        priority_config = {
            'critical': {'emoji': ':rotating_light:', 'color': '#FF0000'},
            'high': {'emoji': ':warning:', 'color': '#FFA500'},
            'normal': {'emoji': ':x:', 'color': '#FF6B6B'},
            'low': {'emoji': ':grey_exclamation:', 'color': '#808080'}
        }
        
        priority_style = priority_config.get(priority, priority_config['normal'])
        
        message = {
            "attachments": [
                {
                    "color": priority_style['color'],
                    "blocks": [
                        {
                            "type": "header",
                            "text": {
                                "type": "plain_text",
                                "text": f"{priority_style['emoji']} Airflow {notification_type.title()}: {dag.dag_id}"
                            }
                        },
                        {
                            "type": "section",
                            "fields": [
                                {"type": "mrkdwn", "text": f"*Priority:* {priority.title()}"},
                                {"type": "mrkdwn", "text": f"*Environment:* {dag.tags.get('env', 'unknown')}"},
                                {"type": "mrkdwn", "text": f"*Owner:* {dag.owner}"},
                                {"type": "mrkdwn", "text": f"*Execution:* {context['execution_date']}"}
                            ]
                        }
                    ]
                }
            ]
        }
        
        # Add mentions for high priority failures
        if priority in ['critical', 'high'] and config.get('mentions'):
            mention_text = ' '.join(config[&a