Notify about backup with mail

RUNBOOK.md

@@ -47,6 +47,37 @@ Run once, by hand, on the server:
    # create a remote named "scaleway", type S3, matching your Scaleway
    # Object Storage credentials and region
    ```
+7. Set up email notifications (optional — skip this if you don't want mail):
+   Install a mail transport agent (choose one):
+   ```bash
+   # Option A: mailutils (Debian/Ubuntu) — includes /usr/bin/mail
+   apt install -y mailutils
+
+   # Option B: msmtp + mailutils (lightweight, no full MTA)
+   apt install -y msmtp msmtp-mta mailutils
+   ```
+   Configure the recipient address. Either set `MAIL_TO` in the environment
+   (`/etc/environment` or the cron file itself) or edit `borg-backup.sh`:
+   ```
+   MAIL_TO="${MAIL_TO:-you@example.com}"
+   ```
+   If using `msmtp`, configure `/etc/msmtprc`:
+   ```
+   # /etc/msmtprc — example for Gmail SMTP
+   defaults
+   auth           on
+   tls            on
+   tls_trust_file /etc/ssl/certs/ca-certificates.crt
+
+   account        default
+   host           smtp.gmail.com
+   port           587
+   from           backup-sender@gmail.com
+   user           backup-sender@gmail.com
+   password       your-app-password
+   ```
+   The script auto-detects which command is available (`mail` → `sendmail` → `msmtp`)
+   and falls back silently if none is present — notifications are never fatal.
 
 ## 2. Deploying the Scripts
 
@@ -62,9 +93,9 @@ chmod +x /opt/backup-agent/dump_db.sh
 ## 3. Scheduling
 
 Add a cron entry to run the backup daily, off-peak:
-
 ```
 # /etc/cron.d/borg-backup
+MAIL_TO=you@example.com
 30 2 * * * root /opt/backup-agent/borg-backup.sh >> /var/log/borg/cron.log 2>&1
 ```
 

borg-backup.sh

@@ -58,6 +58,10 @@ REQUIRED_CMDS=(borg rclone docker timeout flock date find)
 
 # =================================================================
 
+# Email notification (set to your address to receive backup summary).
+# Leave empty to skip notifications. The script auto-detects mail/sendmail/msmtp.
+MAIL_TO="${MAIL_TO:-}"
+
 SELF="$(readlink -f "$0")"
 mkdir -p "$LOGDIR"
 LOGFILE="${BORG_BACKUP_LOGFILE:-$LOGDIR/backup-$(date +%Y-%m-%d-%H%M%S).log}"
@@ -89,6 +93,68 @@ run_cmd() {
     "$@"
 }
 
+# Detect available mail transport. Returns the command name or empty string.
+find_mail_cmd() {
+    for cmd in mail sendmail msmtp; do
+        command -v "$cmd" >/dev/null 2>&1 && { echo "$cmd"; return 0; }
+    done
+    return 1
+}
+
+# Send an email notification about the backup result.
+# Called from cleanup() so the log file is complete.
+# Non-fatal — mail failures do not affect the backup exit code.
+send_notification() {
+    local exit_code=$1 status started ended
+    [[ -n "$MAIL_TO" ]] || return 0
+
+    local mail_cmd
+    mail_cmd="$(find_mail_cmd)" || { log "Notification skipped: no mail command found"; return 0; }
+
+    if [ "$exit_code" -eq 0 ]; then
+        status="SUCCESS"
+    else
+        status="FAILED (exit $exit_code)"
+    fi
+
+    started="$(head -1 "$LOGFILE" 2>/dev/null | sed -n 's/^\[\(.*\)\].*/\1/p' || echo "?")"
+    ended="$(date '+%F %T')"
+
+    # Build message body with headers and log tail.
+    {
+        echo "Subject: Backup $status - $(hostname -s)"
+        echo "To: $MAIL_TO"
+        echo ""
+        echo "===== Backup Summary ====="
+        echo "Host:    $(hostname -f)"
+        echo "Archive: $ARCHIVE"
+        echo "Status:  $status"
+        echo "Started: $started"
+        echo "Ended:   $ended"
+        echo "Log:     $LOGFILE"
+        echo ""
+        echo "----- Last 80 lines of backup log -----"
+        tail -80 "$LOGFILE" 2>/dev/null || echo "(log unavailable)"
+    } | case "$mail_cmd" in
+        mail)
+            mail -s "Backup $status - $(hostname -s)" "$MAIL_TO"
+            ;;
+        sendmail)
+            sendmail "$MAIL_TO"
+            ;;
+        msmtp)
+            msmtp "$MAIL_TO"
+            ;;
+    esac
+
+    local rc=$?
+    if [ "$rc" -eq 0 ]; then
+        log "Notification sent to $MAIL_TO (via $mail_cmd)"
+    else
+        log "WARNING: notification via $mail_cmd failed (exit $rc)"
+    fi
+}
+
 container_running() {
     [[ "$(docker inspect -f '{{.State.Running}}' "$1" 2>/dev/null || echo false)" == "true" ]]
 }
@@ -143,6 +209,7 @@ cleanup() {
         log "=== Backup FAILED (exit $exit_code) ==="
     fi
     log "Full log: $LOGFILE"
+    send_notification "$exit_code"
 }
 
 # Returns 0 if the repo is encrypted, 1 if not.