SMTP Email Alerter integration + make generic Alerter steps

[strickvl]

The PR adds a new SMTP Email Alerter integration to ZenML, enabling users to send email notifications on pipeline steps events. It also implements a unified alerter approach with a standardized AlerterMessage model across all alerter types.

Key Features

• New SMTP Email Alerter Integration

  • Support for HTML and plain text emails
  • Professional HTML email formatting
  • Proper traceback formatting in emails
  • Markdown-to-HTML conversion for better email display
  • Support for common email providers like Gmail, Outlook, etc.

• Unified Alerter Architecture

  • Standardized AlerterMessage model for consistent alerter interfaces
  • Generic alerter_post_step and alerter_ask_step for all alerter types
  • Improved type handling across alerter components
  • Proper deprecation warnings for specialized alerter steps

• Enhanced Alerter Hooks (New)

  • Updated alerter_failure_hook and alerter_success_hook to use structured AlerterMessage format
  • Hooks now provide better organized alerts with title, body, and metadata fields
  • Full backwards compatibility with graceful fallback to string format
  • Deprecation warnings when using legacy string format with alerter.post()
  • Comprehensive unit tests for both AlerterMessage and string formats

• Bug Fixes

  • Fixed unused default_subject variable in SMTP Email Alerter component
  • Resolved mypy type errors throughout alerter components
  • Improved type handling for AlerterMessage vs. string input
  • Fixed docstring errors in SMTP alerter to pass darglint validation

Screenshot

Tests run

• SMTP Email Alerter can be installed and registered with server connections
• Hooks work correctly when configured
• Emails are sent with proper formatting
• Integration with OpenAI hooks works seamlessly
• Markdown formatting is correctly converted to HTML
• Type checking passes without errors
• Unit tests for alerter hooks with both AlerterMessage and legacy formats
• Backwards compatibility verified for existing hook usage

Completed TODOs

• [x] Ask @znegrin for help designing / choosing a new logo for this integration / alerter
• [x] Ask someone from product team (@schustmi ?) to upload a logo for this integration / alerter to the public s3 logos bucket.
• [x] Implement structured AlerterMessage format for alerter hooks
• [x] Add comprehensive documentation for hook usage with all alerter types

Manual Testing with Example Pipelines

All three alerters have been successfully tested with example pipelines:

• Discord Alerter: Pipeline Run

  • ✅ alerter_post_step working
  • ✅ alerter_ask_step working
  • ✅ Success hooks working
  • ✅ Fixed unclosed connector warnings
  • ✅ Hooks using AlerterMessage format

• Slack Alerter: Pipeline Run

  • ✅ alerter_post_step working
  • ✅ alerter_ask_step working (requires bot to be invited to channel)
  • ✅ Custom blocks and formatting working
  • ✅ Success hooks working
  • ✅ Hooks using AlerterMessage format

• SMTP Email Alerter: Pipeline Run

  • ✅ Plain text emails working
  • ✅ HTML emails with default template working
  • ✅ Custom HTML emails working
  • ✅ Email-specific success hooks working
  • ✅ Generic hooks with AlerterMessage format

Test code for all three alerters can be found in this Gist.

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📝 Walkthrough

Walkthrough

This pull request introduces SMTP email alerting capabilities into the ZenML framework. Documentation is updated to explain the new SMTP Email Alerter, its configuration, usage, and security advice. In the codebase, exception handling in failure hooks has been streamlined using standard traceback formatting and a markdown-to-HTML conversion helper was added for improved email message formatting. Additionally, a new constant for SMTP email integration is defined and several new components—including integrations, alerters, flavors, hooks, and post steps—were implemented to support the new email notification functionality.

Changes

File(s)	Changes
docs/book/.../alerters.md docs/book/.../smtp_email.md	Updated Alerters documentation to include details on SMTP Email Alerter and added new documentation outlining its configuration, usage, and security guidelines.
src/zenml/hooks/alerter_hooks.py src/zenml/integrations/openai/hooks/open_ai_failure_hook.py	Revised failure hook implementations to replace Rich formatting with standard Python traceback formatting and added a helper to convert markdown to HTML. Updated model name references in OpenAI hooks.
src/zenml/integrations/constants.py	Added a new constant: SMTP_EMAIL = "smtp_email".
src/zenml/integrations/smtp_email/...	Introduced the SMTP Email integration through multiple new files, including integration classes, alerter implementation (with methods for recipient retrieval, HTML body creation, and sending alerts), flavors, hooks, and a pipeline post step.

Sequence Diagram(s)

sequenceDiagram
    participant Step as Pipeline Step
    participant Hook as SMTP Email Alerter Failure Hook
    participant Alerter as SMTPEmailAlerter
    participant SMTP as SMTP Server

    Step->>Hook: Trigger failure event
    Hook->>Alerter: Build email payload & parameters
    Alerter->>SMTP: Connect (with TLS/auth) and send email
    SMTP-->>Alerter: Acknowledgement of sent email
    Alerter-->>Hook: Return success/failure status

Poem

Oh, I'm a rabbit, hopping with glee,
New email alerts are here for all to see!
From error hooks to SMTP flow,
My code garden is set to grow.
I nibble on bugs, then bounce away—
A techy tale in every byte of day! 🐇💌

✨ Finishing Touches

🧪 Generate unit tests

• [ ] Create PR with unit tests
• [ ] Post copyable unit tests in a comment
• [ ] Commit unit tests in branch feature/email-alerter

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[strickvl]

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[htahir1]

@strickvl conflicts need a fixing :-) Just soft ping

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Documentation Link Check Results

❌ Absolute links check failed There are broken absolute links in the documentation. See workflow logs for details ✅ Relative links check passed _{Last checked: 2025-09-03 05:02:07 UTC}

[strickvl]

@bugbot run

[strickvl]

@bugbot run

[strickvl]

@codex review

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[htahir1]

Closing due to staleness - feel free to open again whenever you are ready :-)