optimize caching of upstream responses

Especially tarballs, which were not being cached correctly before.

Author: rmg

entrypoint.sh

@@ -15,4 +15,7 @@ export npm_config_registry=${npm_config_registry:-https://registry.npmjs.org}
 # necessary because nginx requires a resolver when upstreams are dynamic
 dnsmasq --listen-address=127.0.0.1 --user=root
 
+# in case it hasn't been created as a tmpfs already
+mkdir -p /tmp/npm
+
 exec /usr/local/openresty/bin/openresty -c /nginx.conf $*

nginx.conf

@@ -18,7 +18,13 @@ http {
     default_type  application/octet-stream;
     sendfile        on;
     keepalive_timeout  65;
-    proxy_cache_path  /tmp/npm-cache levels=1:2 keys_zone=STATIC:10m inactive=24h max_size=1g;
+    proxy_cache_path  /tmp/npm/cache levels=1:2 keys_zone=NPM:10m inactive=90d max_size=5g;
+    proxy_temp_path   /tmp/npm/temp;
+    proxy_cache_lock  on;
+    log_format upstreamlog '$remote_addr - $remote_user [$time_local] '
+                           '"$request" $status $body_bytes_sent '
+                           '"$http_referer" "$http_user_agent" "$upstream_cache_status"';
+    access_log logs/access.log upstreamlog;
     server {
         listen       4873;
         set $npm_config_registry '';
@@ -38,16 +44,23 @@ http {
         location ~ ^/.*\.tgz$ {
             resolver               127.0.0.1 ipv6=off;
             proxy_pass             $npm_config_registry;
-            proxy_cache            STATIC;
-            proxy_cache_valid      200  1d;
+            proxy_cache            NPM;
+            proxy_ignore_headers   X-Accel-Redirect X-Accel-Expires X-Accel-Limit-Rate X-Accel-Buffering X-Accel-Charset Expires Cache-Control Set-Cookie Vary;
+            # npm package tarballs are NEVER supposed to change
+            proxy_cache_revalidate off;
+            proxy_cache_valid      200  90d;
             proxy_cache_use_stale  error timeout invalid_header updating http_500 http_502 http_503 http_504;
         }
         location / {
             resolver               127.0.0.1 ipv6=off;
             proxy_pass             $npm_config_registry;
             proxy_buffers          32 1m;
-            proxy_cache            STATIC;
-            proxy_cache_valid      200  1d;
+            proxy_cache            NPM;
+            # need nginx-1.11.10 for this, which isn't in openresty yet:
+            # proxy_cache_background_update on;
+            proxy_cache_revalidate on;
+            # let our metadata be 20 minutes old, at most
+            proxy_cache_valid      200  20m;
             proxy_cache_use_stale  error timeout invalid_header updating http_500 http_502 http_503 http_504;
             # need to disable encoding in order to be able to filter the response body
             proxy_set_header       Accept-Encoding "";