nginx: use lua_shared_dict for config

Author: rmg

nginx.conf

@@ -25,21 +25,24 @@ http {
                            '"$request" $status $body_bytes_sent '
                            '"$http_referer" "$http_user_agent" "$upstream_cache_status"';
     access_log logs/access.log upstreamlog;
+
+    lua_shared_dict npmConfig 32k;
+    init_by_lua_block {
+        local npmConfig = ngx.shared.npmConfig
+        local registry = os.getenv("npm_config_registry"):gsub("/+$", "")
+        local pattern = registry:gsub("%.", "%%."):gsub("%-", "%%-")
+        -- escape . and - which have special meaning in Lua patterns
+        npmConfig:set('npm_config_registry', registry)
+        npmConfig:set('npm_upstream_pattern', pattern)
+        -- ngx.log(ngx.ERR, 'using upstream base: ', registry)
+        -- ngx.log(ngx.ERR, 'using upstream pattern: ', pattern)
+    }
+
     server {
         listen       4873;
         set $npm_config_registry '';
-        set $upstream_base '';
-        set_by_lua_block $upstream_base {
-            local upstream = os.getenv("npm_config_registry")
-            -- escape . and - which have special meaning in Lua patterns
-            upstream = upstream:gsub("%.", "%%."):gsub("%-", "%%-"):gsub("/+$", "")
-            -- ngx.log(ngx.ERR, 'using upstream base:', upstream)
-            return upstream
-        }
         set_by_lua_block $npm_config_registry {
-            local upstream = os.getenv("npm_config_registry"):gsub("/+$", "")
-            -- ngx.log(ngx.ERR, 'using upstream server:', upstream)
-            return upstream
+            return ngx.shared.npmConfig:get('npm_config_registry')
         }
         location ~ ^/.*\.tgz$ {
             root               /tmp/npm/store;
@@ -64,7 +67,8 @@ http {
             }
             # replace all occurances of, eg. https://registry.npmjs.org with http://127.0.0.1:4873
             body_filter_by_lua_block {
-                local upstream = ngx.var.upstream_base
+                local npmConfig = ngx.shared.npmConfig
+                local upstream = npmConfig:get('npm_upstream_pattern')
                 -- need to construct URL because we may be proxying http<->https
                 local base = ngx.var.scheme .. '://' .. ngx.var.http_host
                 -- ngx.log(ngx.ERR, "Modifying JSON of " .. ngx.var.uri .. " to replace '" .. upstream .. "' with '" .. base .. "'")