commit: a0a311e6e91ba167d2350e118db09717b2c8eb4b parent d4501dafce546ee27f9901161354a0a4dd5ad059 Author: Drew DeVault <sir@cmpwn.com> Date: Mon, 17 May 2021 09:05:43 -0400 aerc/mbsync/postfixDiffstat:
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diff --git a/content/blog/aerc-with-mbsync-postfix.md b/content/blog/aerc-with-mbsync-postfix.md @@ -0,0 +1,116 @@ +--- +title: aerc, mbsync, and postfix for maximum comfy offline email +date: 2021-05-17 +--- + +I am the original author of the [aerc mail client][0], though my official +relationship with it today is marginal at best. I think that, with hindsight, +I've come to understand that the "always online" approach of aerc's IMAP +implementation is less than ideal. The next email client (which will exist at +some point!) will improve on this design, but, since it's still my favorite +email client despite these flaws, they will have to be worked around. + +[0]: https://aerc-mail.org + +To this end, I have updated my personal aerc setup to take advantage of its +[Maildir][1] support instead of having it use IMAP directly, then delegate IMAP +to [isync][2], a fork of mbsync, and SMTP to a local postfix instance. This +brings a much-needed level of robustness to the setup, as my Maildirs are +available offline or on a flaky connection, and postfix will handle queueing and +redelivery of outgoing emails in similar conditions.[^1] This allows me to read +and reply to email entirely offline, and have things sync up automatically when +a connection becomes available. + +[1]: https://en.wikipedia.org/wiki/Maildir +[2]: https://isync.sourceforge.io + +[^1]: Postfix is probably overkill for this, but hey, it's what I know. + +The mbsync configuration format is kind of weird, but it is pretty flexible. My +config file ended up looking like this: + +``` +IMAPAccount migadu +Host imap.migadu.com +User sir@cmpwn.com +Pass [...] +SSLType IMAPS + +MaildirStore local +Path ~/mail/ +INBOX ~/mail/INBOX +SubFolders Verbatim + +IMAPStore migadu +Account migadu + +Channel primary +Far :migadu: +Near :local: +Patterns INBOX Archive Sent Junk +Expunge Both +``` + +The password can be configured to run an external command if you prefer to +integrate this with your keyring or password manager. I updated my aerc +`accounts.conf` as well, which was straightforward: + +``` +[Drew] +source = maildir://~/mail +outgoing = /usr/sbin/sendmail +from = Drew DeVault <sir@cmpwn.com> +copy-to = Sent +``` + +Running `mbsync primary` at this point is enough to fetch these mailboxes from +IMAP and populate the local Maildirs, which can then be read with aerc. I set up +a simple cronjob to run this every minute to keep it up to date: + +``` +* * * * * chronic mbsync primary +``` + +chronic is a small utility from [moreutils][3] which converts reasonably behaved +programs that return a nonzero exit status into the back-asswards behavior cron +expects, which is that printing text to stdout means an error occurred and any +status code, successful or not, is disregarded. You might want to tweak this +further, perhaps by just directing all output into /dev/null instead, if you +don't want failed syncs to fill up your Unix mail spool. + +[3]: https://joeyh.name/code/moreutils/ + +mbsync is bidirectional (it is recommended to leave `Expunge both` out of your +config until you've tested the setup), so deleting or archiving emails in aerc +will mirror the changes in IMAP as well. + +Postfix is a lot more annoying to configure. You should assume that what I did +here isn't going to work for you without additional changes and troubleshooting. +I started with an `/etc/postfix/sasl_passwd` file like this: + +``` +[smtp.migadu.com]:465 sir@cmpwn.com:password +``` + +The usual `postmap /etc/postfix/sasl_passwd` applies here to create or update +the database file. Then I moved on to `main.cf`: + +``` +# Allows localhost to relay mail +mynetworks = 127.0.0.0/8 + +# SMTP server to relay mail through +relayhost = [smtp.migadu.com]:465 + +# Auth options for SMTP relay +smtp_sasl_auth_enable = yes +smtp_sasl_password_maps = lmdb:/etc/postfix/sasl_passwd + +# ¯\_(ツ)_/¯ +smtp_tls_security_level = encrypt +smtp_tls_wrappermode = yes +smtp_use_tls = yes +smtp_sasl_security_options = +``` + +Good luck!