From edb1fb9b3dbeabae2868af38b646539cd12eb5be Mon Sep 17 00:00:00 2001
From: Christian Pointner <equinox@spreadspace.org>
Date: Mon, 20 Oct 2014 01:20:17 +0200
Subject: daq: replaced non-working fetch lock with limit_conn module of nginx

---
 src/daq/nginx-lua/s5-nginx.lua | 60 ++++++++++++++++--------------------------
 1 file changed, 23 insertions(+), 37 deletions(-)

(limited to 'src/daq/nginx-lua')

diff --git a/src/daq/nginx-lua/s5-nginx.lua b/src/daq/nginx-lua/s5-nginx.lua
index 673ccba..f1e3719 100644
--- a/src/daq/nginx-lua/s5-nginx.lua
+++ b/src/daq/nginx-lua/s5-nginx.lua
@@ -35,15 +35,16 @@
 -- http {
 --   .....
 --
---   lua_shared_dict sfive 64k;
---   lua_shared_dict sfive_locks 64k;
+--   lua_shared_dict sfive 32k;
 --   lua_shared_dict sfive_data 64m;
 --   init_by_lua 's5 = require "s5-nginx.lua"';
 --   init_worker_by_lua 's5.init_worker(5)';
+--   limit_conn_zone $server_name zone=perserver:32k;
 --
 --   .....
 --
 --   server {
+--     server_name somename;
 --
 --   .....
 --
@@ -55,7 +56,7 @@
 --       allow 127.0.0.1;
 --       allow ::1;
 --       deny  all;
---
+--       limit_conn perserver 1;
 --       content_by_lua 's5.fetch()';
 --     }
 --
@@ -64,8 +65,6 @@
 -- }
 --
 
-locks = require "resty.lock"
-
 local _SFIVE = {}
 
 -----------------------------------------------
@@ -106,43 +105,30 @@ function _SFIVE.log()
 end
 
 function _SFIVE.fetch()
-   local lock = locks:new("sfive_locks", { exptime = nil, timeout = 0.001 })
-   local ok, err = lock:lock("fetch")
-   if not ok then
-      if err == "timeout" then
-         ngx.exit(ngx.HTTP_SERVICE_UNAVAILABLE)
-      else
-         ngx.log(ngx.ERR, "SFive(fetch): failed to acquire fetch lock: " .. err)
-         ngx.exit(ngx.HTTP_INTERNAL_SERVER_ERROR)
+   ngx.log(ngx.INFO, "SFive(fetch): client connected")
+   while true do
+      logs = sfive_data:get_keys()
+      for i, k in ipairs(logs) do
+         local ok, err = ngx.say(sfive_data:get(k))
+         if not ok then
+            ngx.log(ngx.ERR, "SFive(fetch): failed to send data set (" ..  err .. ") - disconnecting client")
+            return
+         end
+         sfive_data:delete(k)
       end
-   else
-      ngx.log(ngx.INFO, "SFive(fetch): client connected")
-      while true do
-         logs = sfive_data:get_keys()
-         for i, k in ipairs(logs) do
-            local ok, err = ngx.say(sfive_data:get(k))
+      ngx.flush()
+      local idx, err = sfive:get("log:idx")
+      if not idx then
+         ngx.log(ngx.ERR, "SFive(fetch): failed to get log index: " .. err)
+      else
+         if idx >= config.log_max_index then
+            local ok, err = sfive:replace("log:idx", 0)
             if not ok then
-               ngx.log(ngx.ERR, "SFive(fetch): failed to send data set (" ..  err .. ") - disconnecting client")
-               lock:unlock("fetch")
-               return
-            end
-            sfive_data:delete(k)
-         end
-         ngx.flush()
-         local idx, err = sfive:get("log:idx")
-         if not idx then
-            ngx.log(ngx.ERR, "SFive(fetch): failed to get log index: " .. err)
-         else
-            if idx >= config.log_max_index then
-               local ok, err = sfive:replace("log:idx", 0)
-               if not ok then
-                  ngx.log(ngx.ERR, "SFive(init): reseting log index counter failed: " .. err)
-               end
+               ngx.log(ngx.ERR, "SFive(init): reseting log index counter failed: " .. err)
             end
          end
-         ngx.sleep(0.1)
       end
-      lock:unlock("fetch")
+      ngx.sleep(0.1)
    end
 end
 
-- 
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