EmailOperator for notifications in Apache Airflow - Step-by-Step Execution

Process Flow - EmailOperator for notifications

Start DAG run

↓

Trigger EmailOperator

↓

Prepare email content

↓

Connect to SMTP server

↓

Send email

↓

Email sent successfully?

No→Log error

Yes↓

End EmailOperator task

This flow shows how Airflow's EmailOperator sends an email notification during a DAG run, connecting to SMTP and handling success or failure.

Execution Sample

Apache Airflow

from airflow.operators.email import EmailOperator
email_task = EmailOperator(
    task_id='send_email',
    to='[e-mail]',
    subject='DAG Notification',
    html_content='<p>Your DAG has completed.</p>'
)
email_task.execute(context={})

This code creates and runs an EmailOperator task that sends an email notification with a subject and HTML content.

Process Table

Step	Action	Evaluation	Result
1	Start EmailOperator execution	N/A	Ready to send email
2	Prepare email content	to='[e-mail]', subject='DAG Notification', html_content='<p>Your DAG has completed.</p>'	Email content ready
3	Connect to SMTP server	SMTP server reachable?	Connection established
4	Send email	Send email via SMTP	Email sent successfully
5	Confirm email sent	Email delivery status	Success confirmed
6	End EmailOperator task	N/A	Task completed

💡 Email sent successfully, task ends normally

Status Tracker

Variable	Start	After Step 2	After Step 4	Final
to	''	'[e-mail]'	'[e-mail]'	'[e-mail]'
subject	''	'DAG Notification'	'DAG Notification'	'DAG Notification'
html_content	''	'<p>Your DAG has completed.</p>'	'<p>Your DAG has completed.</p>'	'<p>Your DAG has completed.</p>'
smtp_connection	None	None	Connected	Closed after send
email_status	None	None	Sent	Confirmed

Key Moments - 3 Insights

Why does the EmailOperator need SMTP server connection?

Because the EmailOperator sends emails by connecting to an SMTP server, as shown in step 3 of the execution_table. Without this connection, the email cannot be sent.

What happens if the SMTP server is not reachable?

If the SMTP server is unreachable, the EmailOperator will fail to send the email and log an error, as indicated by the 'No' branch in the concept_flow after 'Email sent successfully?'.

Why do we provide 'html_content' instead of plain text?

The EmailOperator supports HTML content to allow formatted emails. In the execution_table step 2, 'html_content' is prepared to send a nicely formatted message.

Visual Quiz - 3 Questions

Look at the execution_table, what is the email_status variable after step 4?

A None

B Sent

C Connected

D Confirmed

💡 Hint

Check variable_tracker column 'After Step 4' for 'email_status'

At which step does the EmailOperator confirm the email was sent successfully?

A Step 5

B Step 3

C Step 4

D Step 6

💡 Hint

Look at execution_table row with 'Confirm email sent'

If the SMTP server is unreachable, which part of the concept_flow will be triggered?

A Trigger EmailOperator

B Prepare email content

C Log error

D End EmailOperator task

💡 Hint

Refer to concept_flow decision after 'Email sent successfully?' with 'No' branch

Concept Snapshot

EmailOperator sends emails in Airflow DAGs.
Set 'to', 'subject', and 'html_content' to define the email.
It connects to SMTP server to send the email.
If SMTP fails, it logs an error.
Use execute() to run the task in code.

Full Transcript

The EmailOperator in Airflow sends email notifications during DAG runs. It starts by preparing the email content including recipient, subject, and HTML body. Then it connects to the SMTP server to send the email. If the connection and sending succeed, the task completes successfully. If the SMTP server is unreachable, the operator logs an error and fails. Variables like 'to', 'subject', and 'html_content' hold the email details, while 'smtp_connection' tracks the connection state and 'email_status' tracks sending status. This flow ensures notifications are sent reliably during workflows.