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Send email

A callable workflow that sends an email through any SMTP server, with both STARTTLS (port 587) and SSL (port 465) supported. The SMTP password is sensitive — store it in H2O Secure Store and pass it in as a secret input (secret: true), so the value is redacted from logs.

Workflow​

id: send-email
name: Send Email

trigger:
  callable: true

inputs:
  smtp_host:
    type: string
    required: true
    description: "SMTP server hostname"
  smtp_port:
    type: string
    default: "587"
    description: "SMTP server port (587 for STARTTLS, 465 for SSL)"
  smtp_user:
    type: string
    required: true
    description: "SMTP authentication username"
  smtp_password:
    type: string
    required: true
    secret: true
    description: "SMTP authentication password"
  from_addr:
    type: string
    required: true
    description: "Sender email address"
  to_addr:
    type: string
    required: true
    description: "Recipient email address (comma-separated for multiple)"
  subject:
    type: string
    required: true
    description: "Email subject line"
  body:
    type: string
    required: true
    description: "Email body text"

jobs:
  send:
    name: "Send email"
    timeout: "1m"
    steps:
      - name: "Send email via SMTP"
        env:
          SMTP_HOST: "${{ .inputs.smtp_host }}"
          SMTP_PORT: "${{ .inputs.smtp_port }}"
          SMTP_USER: "${{ .inputs.smtp_user }}"
          SMTP_PASSWORD: "${{ .inputs.smtp_password }}"
          FROM_ADDR: "${{ .inputs.from_addr }}"
          TO_ADDR: "${{ .inputs.to_addr }}"
          SUBJECT: "${{ .inputs.subject }}"
          BODY: "${{ .inputs.body }}"
        run: |
          python3 -c "
          import os, smtplib
          from email.message import EmailMessage

          msg = EmailMessage()
          msg['From'] = os.environ['FROM_ADDR']
          msg['To'] = os.environ['TO_ADDR']
          msg['Subject'] = os.environ['SUBJECT']
          msg.set_content(os.environ['BODY'])

          port = int(os.environ['SMTP_PORT'])
          if port == 465:
              smtp = smtplib.SMTP_SSL(os.environ['SMTP_HOST'], port)
          else:
              smtp = smtplib.SMTP(os.environ['SMTP_HOST'], port)
              smtp.starttls()

          smtp.login(os.environ['SMTP_USER'], os.environ['SMTP_PASSWORD'])
          smtp.send_message(msg)
          smtp.quit()
          print(f'Email sent to {os.environ[\"TO_ADDR\"]}')
          "

Calling it from your workflow​

Reference your stored SMTP password with ${{ .secrets.<name> }}:

secrets:
  - name: workspaces/<workspace-id>/secrets/smtp-password
    as: smtp_password

jobs:
  notify:
    workflow:
      name: send-email
      inputs:
        smtp_host: "smtp.gmail.com"
        smtp_port: "587"
        smtp_user: "workflows@example.com"
        smtp_password: "${{ .secrets.smtp_password }}"
        from_addr: "workflows@example.com"
        to_addr: "team@example.com"
        subject: "Workflow completed"
        body: "The training pipeline finished successfully."
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