feat: send mailings over MailJet smtp in dedicated worker process

config/packages/messenger.yaml

@@ -12,6 +12,29 @@ framework:
                 retry_strategy:
                     max_retries: 3
                     multiplier: 2
+            # Bulk teamer mailings, kept off "async" so that a mailing of several hundred
+            # recipients cannot delay a password reset. Its own cron worker consumes this
+            # queue and nothing else; the two never see each other's messages, because the
+            # doctrine transport filters on the queue_name column. See docs/operations.md
+            # for both cron entries.
+            #
+            # The retry delays are spelled out because the default is one second: with a
+            # multiplier alone, all three retries of a mail are spent within seconds, so a
+            # short hiccup at the mail provider would drop a whole mailing into "failed" at
+            # once - the very thing sending one message per recipient is meant to avoid.
+            # A minute, three and nine outlive any realistic blip and span several runs of
+            # a worker that only lives for a few minutes at a time.
+            mailing:
+                dsn: '%env(MESSENGER_TRANSPORT_DSN)%'
+                options:
+                    queue_name: mailing
+                    use_notify: true
+                    check_delayed_interval: 60000
+                retry_strategy:
+                    max_retries: 3
+                    delay: 60000
+                    multiplier: 3
+                    max_delay: 900000
             failed: 'doctrine://default?queue_name=failed'
             sync: 'sync://'
 
@@ -20,6 +43,9 @@ framework:
             Symfony\Component\Notifier\Message\ChatMessage: async
             Symfony\Component\Notifier\Message\SmsMessage: async
 
+            # only the fan-out, the mails it produces carry an X-Bus-Transport header
+            App\Message\SendTeamerMailing: mailing
+
             # Route your messages to the transports
             # 'App\Message\YourMessage': async
 
@@ -30,3 +56,13 @@ when@dev:
                 Symfony\Component\Mailer\Messenger\SendEmailMessage: sync
                 Symfony\Component\Notifier\Message\ChatMessage: sync
                 Symfony\Component\Notifier\Message\SmsMessage: sync
+                App\Message\SendTeamerMailing: sync
+
+when@test:
+    framework:
+        messenger:
+            routing:
+                Symfony\Component\Mailer\Messenger\SendEmailMessage: sync
+                Symfony\Component\Notifier\Message\ChatMessage: sync
+                Symfony\Component\Notifier\Message\SmsMessage: sync
+                App\Message\SendTeamerMailing: sync