Configuration

To configure a mailer for your application, you need to choose a backend and then specify any necessary configuration values for it. The following backends are provided out of the box:

• smtp (recommended)
• sendmail
• mock (for testing only)

Other backends may be provided by other components.

Once you’ve selected a backend, see its specific documentation to find out what configuration values you need to provide, if any. Configuration values are expressed as constructor arguments for the backend class:

components:
  mailer:
    backend: smtp
    host: primary-smtp.company.com
    ssl: true
    username: foo
    password: bar

This configuration uses primary-smtp.company.com as the server hostname and uses implicit TLS to encrypt the connection. It authenticates with the server using the username foo and the password bar.

The above configuration can be done directly in Python code as follows:

class ApplicationComponent(ContainerComponent):
    async def start(ctx: Context):
        self.add_component(
            'mailer', backend='smtp', host='primary-smtp.company.com', ssl=True,
            username='foo', password='bar')
        await super().start()

Multiple mailers

If you need multiple mailers, you need to specify them via the mailers argument, which is a dictionary of resource names to their backend configuration options:

components:
  mailer:
    mailers:
      smtp_a:
        backend: smtp
        context_attr: mailer1
        host: primary-smtp.company.com
        ssl: true
        username: foo
        password: bar
      smtp_b:
        backend: smtp
        context_attr: mailer2
        host: isp-smtp.provider.com
      sendmail:
        backend: sendmail
        context_attr: mailer3

This configures three mailer resources, named smtp_a, smtp_b and sendmail. Their corresponding context attributes are mailer1, mailer2 and mailer3. If you omit the context_attr option for a mailer, its resource name will be used.