we don't want external software to include internal details like mlog.
slog.Logger is/will be the standard.
we still have mlog for its helper functions, and its handler that logs in
concise logfmt used by mox.
packages that are not meant for reuse still pass around mlog.Log for
convenience.
we use golang.org/x/exp/slog because we also support the previous Go toolchain
version. with the next Go release, we'll switch to the builtin slog.
for reporting addresses that cause DSNs to be returned. that just adds noise.
the admin can add/remove/extend addresses through the webadmin.
in the future, we could send reports with a smtp mail from of
"postmaster+<signed-encoded-recipient>@...", and add the reporting recipient
on the suppression list automatically when a DSN comes in on that address, but
for now this will probably do.
this also has changes to make the dmarc report sending implementation more
similar to the tls reports implementation.
- factor out code to compose a dmarc report message to the message package
(from dmarcdb for reports), it will be shared soon.
- spread emails with dmarc reports over 45 minutes (it runs hourly), with at
most 5 mins in between reports. to prevent bursts of messages. properly abort
all sending attempts at mox shutdown.
- add use of missing error details in an error path.
- fix dmarc report message subject header by adding missing <>'s around report-id.
- fix dmarc report attachment filename syntax by leaving "unique-id" out.
in smtpserver, we store dmarc evaluations (under the right conditions).
in dmarcdb, we periodically (hourly) send dmarc reports if there are
evaluations. for failed deliveries, we deliver the dsn quietly to a submailbox
of the postmaster mailbox.
this is on by default, but can be disabled in mox.conf.
