IMAP Sync updates

IMAP-Sync.md

@@ -1,9 +1,22 @@
-Sync email via IMAP from host1/domain1 to a subfolder on host2/domain2 via a cron/timer. Can be reversed as well, just update `Patterns` to exclude the subfolders from being cross-replicated (looped).
+# IMAP Sync
+
+Sync email via IMAP from `host1/domain1` to a subfolder on `host2/domain2` via a cron/timer. Can be reversed as well, just update `Patterns` to exclude the subfolders from being cross-replicated (looped).
+
+Sync email via IMAP from `host1/domain1` to a local `Maildir` folder via cront/timer. This can be used to restore a backup to either `host1/domain1` or `host2/domain2` as well as by a local MUA (mutt, e.g.).
+
+Note: an argument can be made it's more effecient to sync `host1/domain1` to a local `Maildir` first, then sync the local `Maildir` to `host2/domain2`. This however comes at a cost of risk - what if the local drive is full, fails or has an error? One runs the risk of using a possible corrupt local datastore to sync to `host2/domain2` when the intent is to have multiple verbatim backups of `host1/domain1`. Choose wisely.
+
+## Preparation
+
+Documentation:
 
  - https://isync.sourceforge.io/mbsync.html
+
+Debian package:
+
  - Install the `isync` package: `apt-get update && apt-get install isync`
 
-Passwords for IMAP must be left on disk in plain text
+Passwords for IMAP must be left on disk in plain text:
 
  - Generate "app passwords" at the email providers, host1 can be READ only
  - Keep `${HOME}/.secure` contents on encrypted volume unlocked manually
@@ -12,12 +25,17 @@ The `mbsync` program keeps it's transient index files in `${HOME}/.mbsync/` with
 
 By design, `mbsync` will not delete a destination folder if it's not empty first; this means if you delete a folder and all emails on the source in one step, a sync will break with an error/warning. Instead, delete all emails in the folder first, sync those deletions, then delete the empty folder on the source and sync again. See: https://sourceforge.net/p/isync/mailman/isync-devel/thread/f278216b-f1db-32be-fef2-ccaeea912524%40ojkastl.de/#msg37237271
 
-Simple crontab to run the script:
+## Crontabs
+
+Simple crontabs to run the scripts, 30 minutes apart:
 
 ```
 0 */6 * * * /home/USER/bin/hasync.sh
+30 */6 * * * /home/USER/bin/halocal.sh
 ```
 
+## Config
+
 Main config for the `mbsync` program:
 
 **${HOME}/.mbsyncrc**
@@ -44,6 +62,12 @@ SystemCertificates yes
 PipeLineDepth 1
 #CertificateFile /etc/ssl/certs/ca-certificates.crt
 
+# Local
+MaildirStore local-dest
+Path /home/USER/Maildir/
+AltMap no
+Subfolders Verbatim
+
 # Source map
 IMAPStore imap-src
 Account imap-src-account
@@ -62,9 +86,22 @@ Remove Near
 Expunge Near
 Patterns *
 CopyArrivalDate yes
+
+# Local options
+Channel dmlocal
+Far :imap-src:
+Near :local-dest:
+Sync Pull
+Create Near
+Remove Near
+Expunge Near
+Patterns *
+CopyArrivalDate yes
 ```
 
-This script leverages healthchecks.io to alert on failure; replace XXXXX with the UUID of your monitor URL.
+## Scripts
+
+These scripts leverage https://healthchecks.io to alert on failure; replace XXXXX with the UUID of your monitor URL.
 
 **${HOME}/bin/hasync.sh**
 ```bash
@@ -73,7 +110,7 @@ This script leverages healthchecks.io to alert on failure; replace XXXXX with th
 # vars
 LOGDIR="${HOME}/log"
 TIMESTAMP=$(date +%Y-%m-%d_%H%M)
-LOGFILE="${LOGDIR}/mbsync_${TIMESTAMP}.log"
+LOGFILE="${LOGDIR}/hasync_${TIMESTAMP}.log"
 HCPING="https://hc-ping.com/XXXXXXXXXXXXXXXXXXXXXXXXX"
 
 # preflight
@@ -91,7 +128,38 @@ echo -e "\nEND $(date +%Y-%m-%d_%H%M)\n" >> "${LOGFILE}"
 # report
 if [[ $EC -eq 0 ]]; then
   curl -fsS -m 10 --retry 5 -o /dev/null "${HCPING}"
-  find "${LOGDIR}" -type f -mtime +30 -delete
+  find "${LOGDIR}" -type f -name hasync\* -mtime +30 -delete
+fi
+
+exit $EC
+```
+
+**${HOME}/bin/halocal.sh**
+```bash
+#!/bin/bash
+
+# vars
+LOGDIR="${HOME}/log"
+TIMESTAMP=$(date +%Y-%m-%d_%H%M)
+LOGFILE="${LOGDIR}/halocal_${TIMESTAMP}.log"
+HCPING="https://hc-ping.com/XXXXXXXXXXXXXXXXXXXXXXXXX"
+
+# preflight
+if [[ ! -d "${LOGDIR}" ]]; then
+  mkdir -p "${LOGDIR}"
+fi
+
+# sync
+echo -e "\nBEGIN $(date +%Y-%m-%d_%H%M)\n" >> "${LOGFILE}"
+/usr/bin/mbsync -c ${HOME}/.mbsyncrc -V halocal 1>>"${LOGFILE}" 2>&1
+EC=$?
+echo -e "\nEC: ${EC}" >> "${LOGFILE}"
+echo -e "\nEND $(date +%Y-%m-%d_%H%M)\n" >> "${LOGFILE}"
+
+# report
+if [[ $EC -eq 0 ]]; then
+  curl -fsS -m 10 --retry 5 -o /dev/null "${HCPING}"
+  find "${LOGDIR}" -type f -name halocal\* -mtime +30 -delete
 fi
 
 exit $EC