Keep logging somewhat sane

We don't want an infinitely growing logfile.
Instead we set a reasonable cap, currently 4MiB, and retain one backup.

status-check.sh

@@ -3,11 +3,6 @@
 #set -eux
 
 LOG_FILE="/media/workshop/Projects/openmedianetwork/.omn_watchdog.log"
-touch ${LOG_FILE}
-
-# Redirect all output to LOG_FILE but preserve a link to stdout should we
-# still want to use it
-exec 3>&1 1>>${LOG_FILE} 2>&1
 
 RECIPIENTS=(
     saunders@openworlds.info
@@ -16,7 +11,7 @@ RECIPIENTS=(
 
 URLS=(
     unite.openworlds.info
-    openworlds.info
+    # NOTE: [Currently down] openworlds.info
     pad.openworlds.info
     visionon.tv
     activism.openworlds.info
@@ -35,7 +30,22 @@ SERVICES=(
     #mail.openworlds.info
 )
 
-send_mail() {
+rotate_log()
+{
+    local -n log=$1
+    local max_log=4096 # 4M as we get size in K below
+    local log_size=$(du -k "${log}" | cut -f 1)
+
+    if ((${log_size} > ${max_log})); then
+        # Clobber any previous backup
+        mv -f ${log} ${log}.1
+    fi
+
+    touch ${log}
+}
+
+send_mail()
+{
     local -n error_list=$1
     local error_string=""
 
@@ -48,13 +58,18 @@ send_mail() {
 
     cat mail_template \
         | sed "s/{ERR_LIST}/${error_string}/g" \
-        | msmtp -a omn_server_watch ${RECIPIENTS[@]} 2>/dev/null \
+        | msmtp -a omn_server_watch ${RECIPIENTS[@]} \
         || echo "[ERROR] Failed to send mail!"
 }
 
 declare -A FLAGGED
 
-echo "== $(date)"
+rotate_log LOG_FILE
+# Redirect all output to LOG_FILE but preserve a link to stdout should we
+# still want to use it
+exec 3>&1 1>>${LOG_FILE} 2>&1
+
+echo ">> $(date)"
 echo "== Checking:"
 
 for uri in "${URLS[@]}"; do \