prefecthq / prefect-email

Prefect tasks and subflows for interacting with email

Note

Active development of this project has moved within PrefectHQ/prefect. The code can be found here and documentation here. Please open issues and PRs against PrefectHQ/prefect instead of this repository.

prefect-email

Visit the full docs here to see additional examples and the API reference.

prefect-email is a collection of prebuilt Prefect integrations that can be used to interact with email services.

Getting Started

Integrate with Prefect flows

prefect-email makes sending emails effortless, giving you peace of mind that your emails are being sent as expected.

First, install prefect-email and save your email credentials to a block to run the examples below!

from prefect import flow
from prefect_email import EmailServerCredentials, email_send_message

@flow
def example_email_send_message_flow(email_addresses):
    email_server_credentials = EmailServerCredentials.load("BLOCK-NAME-PLACEHOLDER")
    for email_address in email_addresses:
        subject = email_send_message.with_options(name=f"email {email_address}").submit(
            email_server_credentials=email_server_credentials,
            subject="Example Flow Notification using Gmail",
            msg="This proves email_send_message works!",
            email_to=email_address,
        )

example_email_send_message_flow(["EMAIL-ADDRESS-PLACEHOLDER"])

Outputs:

16:58:27.646 | INFO    | prefect.engine - Created flow run 'busy-bat' for flow 'example-email-send-message-flow'
16:58:29.225 | INFO    | Flow run 'busy-bat' - Created task run 'email [email protected]' for task 'email [email protected]'
16:58:29.229 | INFO    | Flow run 'busy-bat' - Submitted task run 'email [email protected]' for execution.
16:58:31.523 | INFO    | Task run 'email [email protected]' - Finished in state Completed()
16:58:31.713 | INFO    | Flow run 'busy-bat' - Finished in state Completed('All states completed.')

Please note, many email services, like Gmail, require an App Password to successfully send emails. If you encounter an error similar to smtplib.SMTPAuthenticationError: (535, b'5.7.8 Username and Password not accepted..., it's likely you are not using an App Password.

Capture exceptions and notify by email

Perhaps you want an email notification with the details of the exception when your flow run fails.

prefect-email can be wrapped in an except statement to do just that!

from prefect import flow
from prefect.context import get_run_context
from prefect_email import EmailServerCredentials, email_send_message

def notify_exc_by_email(exc):
    context = get_run_context()
    flow_run_name = context.flow_run.name
    email_server_credentials = EmailServerCredentials.load("email-server-credentials")
    email_send_message(
        email_server_credentials=email_server_credentials,
        subject=f"Flow run {flow_run_name!r} failed",
        msg=f"Flow run {flow_run_name!r} failed due to {exc}.",
        email_to=email_server_credentials.username,
    )

@flow
def example_flow():
    try:
        1 / 0
    except Exception as exc:
        notify_exc_by_email(exc)
        raise

example_flow()

Resources

For more tips on how to use tasks and flows in a Collection, check out Using Collections!

Installation

Install prefect-email with pip:

pip install prefect-email

Then, register to view the block on Prefect Cloud:

prefect block register -m prefect_email

Note, to use the load method on Blocks, you must already have a block document saved through code or saved through the UI.

Requires an installation of Python 3.7+.

We recommend using a Python virtual environment manager such as pipenv, conda or virtualenv.

These tasks are designed to work with Prefect 2. For more information about how to use Prefect, please refer to the Prefect documentation.

Saving credentials to block

Note, to use the load method on Blocks, you must already have a block document saved through code or saved through the UI.

Below is a walkthrough on saving block documents through code.

Create a short script, replacing the placeholders.

from prefect_email import EmailServerCredentials

credentials = EmailServerCredentials(
    username="EMAIL-ADDRESS-PLACEHOLDER",
    password="PASSWORD-PLACEHOLDER",  # must be an app password
)
credentials.save("BLOCK-NAME-PLACEHOLDER")

Congrats! You can now easily load the saved block, which holds your credentials:

from prefect_email import EmailServerCredentials

EmailServerCredentials.load("BLOCK_NAME_PLACEHOLDER")

!!! info "Registering blocks"

Register blocks in this module to
[view and edit them](https://orion-docs.prefect.io/ui/blocks/)
on Prefect Cloud:

```bash
prefect block register -m prefect_email
```

A list of available blocks in prefect-email and their setup instructions can be found here.

Feedback

If you encounter any bugs while using prefect-email, feel free to open an issue in the prefect-email repository.

If you have any questions or issues while using prefect-email, you can find help in either the Prefect Discourse forum or the Prefect Slack community.

Feel free to star or watch prefect-email for updates too!

Contributing

If you'd like to help contribute to fix an issue or add a feature to prefect-email, please propose changes through a pull request from a fork of the repository.

Here are the steps:

1. Fork the repository
2. Clone the forked repository
3. Install the repository and its dependencies:

pip install -e ".[dev]"

4. Make desired changes
5. Add tests
6. Insert an entry to CHANGELOG.md
7. Install pre-commit to perform quality checks prior to commit:

pre-commit install

8. git commit, git push, and create a pull request