From caf3b6c90fc9b0bf675f03bef28fcae48dd6bcba Mon Sep 17 00:00:00 2001
From: Filippo Tessarotto <zoeslam@gmail.com>
Date: Wed, 17 Oct 2018 08:44:02 +0200
Subject: [PATCH] Nginx error: log files may be empty

---
 plugins/nginx/nginx_error | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/plugins/nginx/nginx_error b/plugins/nginx/nginx_error
index 6372867a..a0ff11b5 100755
--- a/plugins/nginx/nginx_error
+++ b/plugins/nginx/nginx_error
@@ -122,9 +122,13 @@ http_codes[503]='Service Unavailable'
 do_fetch () {
   local count status_code
   declare -A line_counts
-  while read -r count status_code; do
+  values="$(awk '{print $9}' "$log" | sort | uniq -c)"
+  # Log files may be empty due to logrotation
+  if [ -n "$values" ]; then
+    while read -r count status_code; do
       line_counts[$status_code]=$count
-  done <<< "$(awk '{print $9}' "$log" | sort | uniq -c)"
+    done <<< "$values"
+  fi
 
   for status_code in "${!http_codes[@]}"; do
     echo "error${status_code}.value ${line_counts[$status_code]:-0}"