improve nginx skylinks cache purging (#553)

* purge test

* purge test

* purge test

* purge test

* purge test

* purge test

* purge test

* purge test

docker/nginx/conf.d/client.conf

@@ -71,7 +71,7 @@ server {
 
 		# redirect links with handshake domain on hns subdomain
 		error_page 461 = @hns_domain;
-		if ($hns_domain  != "") {
+		if ($hns_domain != "") {
 			return 461;
 		}
 
@@ -268,6 +268,12 @@ server {
 		include /etc/nginx/conf.d/include/proxy-buffer;
 		include /etc/nginx/conf.d/include/proxy-cache-downloads;
 
+		# redirect purge calls to separate location
+		error_page 462 = @purge;
+		if ($request_method = PURGE) {
+			return 462;
+		}
+
 		limit_conn downloads_by_ip 100; # ddos protection: max 100 downloads at a time
 		add_header Cache-Control "public, max-age=86400"; # allow consumer to cache response
 
@@ -293,6 +299,17 @@ server {
 		proxy_pass http://127.0.0.1/hns/$hns_domain/$request_uri;
 	}
 
+	location @purge {
+		allow 10.0.0.0/8;
+		allow 127.0.0.1/32;
+		allow 172.16.0.0/12;
+		allow 192.168.0.0/16;
+		deny all;
+
+		set $lua_purge_path "/data/nginx/cache/";
+		content_by_lua_file /etc/nginx/conf.d/scripts/purge-multi.lua;
+	}
+
 	location ~ "^/file/([a-zA-Z0-9-_]{46}(/.*)?)$" {
 		include /etc/nginx/conf.d/include/proxy-buffer;
 

docker/nginx/conf.d/scripts/purge-multi.lua

@@ -0,0 +1,68 @@
+-- Tit Petric, Monotek d.o.o., Tue 03 Jan 2017 06:54:56 PM CET
+--
+-- Delete nginx cached assets with a PURGE request against an endpoint
+-- supports extended regular expression PURGE requests (/upload/.*)
+--
+-- https://scene-si.org/2017/01/08/improving-nginx-lua-cache-purge/
+--
+
+function file_exists(name)
+    local f = io.open(name, "r")
+    if f~=nil then io.close(f) return true else return false end
+end
+
+function explode(d, p)
+    local t, ll
+    t={}
+    ll=0
+    if(#p == 1) then return {p} end
+            while true do
+                    l=string.find(p, d, ll, true) -- find the next d in the string
+                    if l~=nil then -- if "not not" found then..
+                            table.insert(t, string.sub(p, ll, l-1)) -- Save it in our array.
+                            ll=l+1 -- save just after where we found it for searching next time.
+                    else
+                            table.insert(t, string.sub(p, ll)) -- Save what's left in our array.
+                            break -- Break at end, as it should be, according to the lua manual.
+                    end
+            end
+    return t
+end
+
+function purge(filename)
+    if (file_exists(filename)) then
+            os.remove(filename)
+    end
+end
+
+function trim(s)
+    return (string.gsub(s, "^%s*(.-)%s*$", "%1"))
+end
+
+function exec(cmd)
+    local handle = io.popen(cmd)
+    local result = handle:read("*all")
+    handle:close()
+    return trim(result)
+end
+
+function list_files(cache_path, purge_pattern)
+    local result = exec("/usr/bin/find " .. cache_path .. " -type f | /usr/bin/xargs --no-run-if-empty -n1000 /bin/grep -El -m 1 '^KEY: " .. purge_pattern .. "' 2>&1")
+    if result == "" then
+            return {}
+    end
+    return explode("\n", result)
+end
+
+if ngx ~= nil then
+    -- list all cached items matching uri
+    local files = list_files(ngx.var.lua_purge_path, ngx.var.uri)
+
+    ngx.header["Content-type"] = "text/plain; charset=utf-8"
+    ngx.header["X-Purged-Count"] = table.getn(files)
+    for k, v in pairs(files) do
+            purge(v)
+    end
+    ngx.say("OK")
+    ngx.exit(ngx.OK)
+end

scripts/blocklist-skylink.sh

@@ -29,25 +29,17 @@ else
     skylinks=("$1") # just single skylink passed as input argument
 fi
 
-####################################################
-# iterate through all servers and block the skylinks
-####################################################
+#########################################################################
+# iterate through all servers, block the skylinks and purge it from cache
+#########################################################################
 for server in "germany.siasky.net" "helsinki.siasky.net" "us-west.siasky.net" "us-va-1.siasky.net" "us-pa-1.siasky.net" "us-pa-2.siasky.net" "siasky.xyz";
 do
-    #############################################################
-    # iterate throught all skylinks and add each one to blocklist
-    #############################################################
     for skylink in "${skylinks[@]}";
     do
         echo ".. ⌁ Blocking skylink ${skylink} on ${server}"
-        ssh -q -t user@${server} 'docker exec sia siac skynet blocklist add '$skylink''
-    done
 
-    ######################################################
-    # purge nginx cache after all the skylinks are blocked
-    ######################################################
-    ssh -q -t user@${server} 'docker exec nginx sh -c "rm -rf /data/nginx/cache/*"'
-    echo ".... 🗑️ Pruned nginx cache on ${server}"
+        ssh -q -t user@${server} "docker exec sia siac skynet blocklist add $skylink && docker exec nginx curl -s -i -X PURGE http://localhost/$skylink | egrep \"^(OK|HTTP|X-)\""
+    done
 done
 
 echo "✓ All done !"