Configure email delivery in production using environment variables

[harisadam]

Looks like Fizzy currently defaults to Sendmail, this update enables developers to switch to SMTP when needed via environment variables.

[arnsteinsm]

Hey! Just wanted to add a quick note: before I found this PR, I ended up doing almost the same SMTP setup in my own fork so I could run Fizzy self-hosted.

I’ve tested the env-based SMTP approach on Coolify (ARM server) using Mailgun, and it works very well.

Thanks for putting it together!

[kevinmcconnell]

Defaulting to sendmail might be surprising, since it's not the usual Rails default.

What do you think about defaulting to smtp instead?

[harisadam]

thats my preference, I think most people use smtp as well, change has been added

[kevinmcconnell]

Nice. Thanks @harisadam!

[kevinmcconnell]

Note that we're currently setting specific SMTP settings in fizzy-saas, which would be overwritten by the settings provided here.

So before we can merge this, we need to resolve that situation. Either fizzy-sass needs to use the same env vars, or maybe invert the order that these environment files get applied so that fizzy-sass can take priority.

cc @jorgemanrubia

[harisadam]

@kevinmcconnell This might be a better approach and make this PR irrelevant:
#1958

[kevinmcconnell]

@harisadam how about we make this all conditional on whether MAILER_DELIVERY_METHOD is set? If it's not set, the default is to leave the config alone. That would make it compatible with our (and other) engines, but still provide a simple way to configure the settings via env var.

[eval]

Maybe allow for 1 env-var SMTP_URL instead of 8?
Shameless self-promotion: I created uri-smtp that extends URI to understand uri's using smtp(s) protocols:

+  config.action_mailer.smtp_settings = URI(ENV.fetch("SMTP_URL")).to_h(format: :am)

-  config.action_mailer.smtp_settings = {
-    address: ENV.fetch("SMTP_ADDRESS", "localhost"),
-    port: ENV.fetch("SMTP_PORT", "587").to_i,
-    domain: ENV.fetch("SMTP_DOMAIN", nil),
-    user_name: ENV.fetch("SMTP_USERNAME", nil),
-    password: ENV.fetch("SMTP_PASSWORD", nil),
-    authentication: ENV.fetch("SMTP_AUTHENTICATION", "plain"),
-    enable_starttls_auto: ENV.fetch("SMTP_ENABLE_STARTTLS_AUTO", "true") == "true"
-  }

The SMTP_URL can now double as MAILER_DELIVERY_METHOD - when it's there, use SMTP otherwise use a fallback.

Besides being more convenient to have 1 var, it also:

• ...has proper defaults.
  e.g. starttls: :always, but not for local development (against e.g. mailcatcher), ports for smtps://.. vs smtp://... etc.
• ...works around a bug in mail-gem v2.8.1 that when setting tls: false, starttls will be ignored
  Probably the reason the rails sample config doesn't contain the tls-setting(?)
• ...provides a consistent config
  e.g. tls: true ánd starttls: true (which makes no sense): URI("smtps://user:pass@gmail.com?starttls=true").starttls #=> false. URI("smtp://gmail.com?authentication=plain").auth #=> nil (prevents net-smtp from raising because there's no authinfo).
  But to start: weird configurations in URI-form are more easily spotted because they look weird.

[kevinmcconnell]

@harisadam fyi I've rebased these changes to resolve the conflicts, and I've made the setup conditional on whether SMTP_ADDRESS is set.

[harisadam]

🚀 @kevinmcconnell thanks looks good to me - sorry I’ve been swamped with work

[kevinmcconnell]

@eval the URL config is an interesting idea, but I think the individual params will probably be more familiar to folks setting up a Fizzy instance. So we'll stick with those for now, and see how that goes. Thanks for the suggestion though.

[kevinmcconnell]

@harisadam no worries at all. Thanks for getting this started! 🙏