From 16070d8b6feb52266adb5bb714295ffcf3a44c0c Mon Sep 17 00:00:00 2001
From: tastytea <tastytea@tastytea.de>
Date: Mon, 19 Oct 2020 04:12:17 +0200
Subject: [PATCH] Tweak and document nginx caching in example.

---
 README.adoc | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/README.adoc b/README.adoc
index 6889582..4e0a052 100644
--- a/README.adoc
+++ b/README.adoc
@@ -27,14 +27,17 @@ tools to generate a HTML list and an RSS generator.
 .nginx config
 [source,nginx]
 --------------------------------------------------------------------------------
-fastcgi_cache_path /var/cache/nginx levels=1:2 keys_zone=fediblock:10m;
+# Use 100 MiB cache with a 1 MiB memory zone (enough for ~8,000 keys).
+# Delete data that has not been accessed for 10 minutes.
+fastcgi_cache_path /var/cache/nginx/fediblock levels=1:2 max_size=100m
+                   keys_zone=fediblock:1m inactive=10m use_temp_path=off;
 fastcgi_cache_key "$scheme$request_method$host$request_uri";
 add_header X-Cache $upstream_cache_status;
 
 server {
     # […]
 
-    expires 1h;
+    expires 30m;
 
     location /add {
         include /etc/nginx/fastcgi_params;
@@ -49,7 +52,8 @@ server {
         fastcgi_param SCRIPT_FILENAME /usr/bin/fediblock-backend-gen_rss;
         fastcgi_param HOME "/var/lib/nginx";
         fastcgi_cache fediblock;
-        fastcgi_cache_valid 200 10m;
+        fastcgi_cache_valid 200 15m; # Cache answers for up to 15 minutes.
+        fastcgi_cache_lock on;  # Relay only one identical request at a time.
     }
 }
 --------------------------------------------------------------------------------