Don’t log recipients when sending mail

[jvdp]

Since production applications typically run with log level info and email adresses should be considered as sensitive data (or personal data under GDPR) we want to prevent them from ending up in the logs. In development mode (with log level debug) they are still logged as part of the Mail::Message object.

While we could add another config option for this (#19293) I propose we fix the privacy issue by doing the right thing by default, and custom log subscribers could be written to restore the old functionality.

(As a bonus, the wording in the logs is now consistent with the event name ;))

[georgeclaghorn]

👍 for not logging personal data when it’s not needed. Can we log the Message-ID instead, so that outbound emails in application logs can still be correlated with mail server logs?

[robzolkos]

I'm not fond of the Delivered mail text as thats not actually what happened. The app has sent the email but it isn't responsible for delivering it or knowledgable if it has been delivered.

Yes the mail is part of a delivery but to call it delivered is not accurate imo.

Everything else about this change however is spot on. Love the removal of private info from logs.

[jvdp]

👍 for not logging personal data when it’s not needed. Can we log the Message-ID instead, so that outbound emails in application logs can still be correlated with mail server logs?

Good idea! Took me a while to get around to this though. I've also run into (and fixed) a bug where auto-generated message ids are not included in the payload. (It seems they aren't generated until you call Mail::Message#encoded.)

I'm not fond of the Delivered mail text as thats not actually what happened. The app has sent the email but it isn't responsible for delivering it or knowledgable if it has been delivered.

Yes the mail is part of a delivery but to call it delivered is not accurate imo.

Everything else about this change however is spot on. Love the removal of private info from logs.

I get where you're coming from but there's also another perspective: Rails has 'delivered' the mail to the subsystem responsible for the next step towards delivery. And it's now consistent with the event name.