Integration with PagerDuty and Slack in Apache Airflow - Step-by-Step Execution

Process Flow - Integration with PagerDuty and Slack

Airflow Task Fails

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Trigger Alert Handler

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Send Alert to PD

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Alert Delivered

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Log Alert

When an Airflow task fails, an alert handler checks where to send the alert. It sends notifications to PagerDuty and Slack, then logs the alert delivery.

Execution Sample

Apache Airflow

def alert_handler(context):
    if 'pagerduty' in context['alert_channels']:
        send_pagerduty_alert(context)
    if 'slack' in context['alert_channels']:
        send_slack_alert(context)
    log_alert(context)

This function sends alerts to PagerDuty and Slack based on the alert channels in the context, then logs the alert.

Process Table

Step	Action	Condition	Result	Output
1	Task fails in Airflow	N/A	Trigger alert_handler	Alert handler called
2	Check if 'pagerduty' in alert_channels	True	Call send_pagerduty_alert	PagerDuty alert sent
3	Check if 'slack' in alert_channels	True	Call send_slack_alert	Slack alert sent
4	Log alert delivery	N/A	Log success	Alert logged
5	End of alert_handler	N/A	Return from function	Alert process complete

💡 All alert channels processed and alert logged, function ends

Status Tracker

Variable	Start	After Step 2	After Step 3	Final
context['alert_channels']	['pagerduty', 'slack']	['pagerduty', 'slack']	['pagerduty', 'slack']	['pagerduty', 'slack']
alert sent to PagerDuty	False	True	True	True
alert sent to Slack	False	False	True	True
alert logged	False	False	False	True

Key Moments - 3 Insights

Why does the alert_handler check for each alert channel separately instead of using else-if?

Because both PagerDuty and Slack alerts can be sent independently if both are in alert_channels, as shown in steps 2 and 3 where both conditions are checked and both alerts sent.

What happens if 'pagerduty' is not in alert_channels?

Step 2 condition becomes False, so send_pagerduty_alert is skipped, but Slack alert can still be sent if present, as shown by the condition checks in the execution_table.

Why is logging done after sending alerts?

Logging confirms alert delivery status after all alert channels are processed, as seen in step 4 where logging happens after both alerts are sent.

Visual Quiz - 3 Questions

Look at the execution table, at which step is the Slack alert sent?

A Step 3

B Step 4

C Step 2

D Step 5

💡 Hint

Check the 'Action' and 'Output' columns in the execution_table for Slack alert sending

According to the variable tracker, what is the value of 'alert sent to PagerDuty' after step 2?

A False

B None

C True

D Undefined

💡 Hint

Look at the 'alert sent to PagerDuty' row under 'After Step 2' in variable_tracker

If 'slack' was removed from alert_channels, how would the execution table change?

A Step 2 would skip sending PagerDuty alert

B Step 3 would skip sending Slack alert

C Step 4 would not log alert delivery

D Step 5 would not be reached

💡 Hint

Refer to the condition checks in steps 2 and 3 in execution_table

Concept Snapshot

Integration with PagerDuty and Slack in Airflow:
- On task failure, alert_handler runs
- Checks alert_channels for 'pagerduty' and 'slack'
- Sends alerts to each channel independently
- Logs alert delivery after sending
- Ensures notifications reach both systems if configured

Full Transcript

When an Airflow task fails, it triggers an alert handler function. This function checks which alert channels are configured in the context, such as PagerDuty and Slack. If PagerDuty is included, it sends an alert there. Similarly, if Slack is included, it sends an alert to Slack. After sending alerts to all configured channels, it logs the alert delivery. This process ensures that notifications are sent to the right places and recorded for tracking.