From f3c1a77d7a4814f3dd3be5dae6d530471a8d58a5 Mon Sep 17 00:00:00 2001
From: Christian Pointner <equinox@spreadspace.org>
Date: Sat, 18 Oct 2014 00:32:21 +0200
Subject: moved to resty-lock for fetch

---
 src/daq/nginx-lua/s5-nginx-fetch.lua | 41 +++++++++++++-----------------------
 src/daq/nginx-lua/s5-nginx-init.lua  | 31 ++++++++++++++++++++-------
 src/daq/nginx-lua/s5-nginx-log.lua   |  4 ++--
 3 files changed, 40 insertions(+), 36 deletions(-)

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

diff --git a/src/daq/nginx-lua/s5-nginx-fetch.lua b/src/daq/nginx-lua/s5-nginx-fetch.lua
index 8bfcf07..8821094 100644
--- a/src/daq/nginx-lua/s5-nginx-fetch.lua
+++ b/src/daq/nginx-lua/s5-nginx-fetch.lua
@@ -33,52 +33,41 @@
 -- Install this by adding the following to your nginx.conf
 --
 -- location /sfive {
---   allow localhost;
+--   allow 127.0.0.1;
+--   allow ::1;
 --   deny  all;
 --
---   lua_check_client_abort on;
 --   content_by_lua_file '/path/to/s5-nginx-fetch.lua';
 -- }
 --
 
-local sfive = ngx.shared.sfive
-
-local function fetch_cleanup()
-   ngx.log(ngx.INFO, "SFive(fetch): cleanup fetch")
-   sfive:delete("fetch:connected")
-end
-
-local ok, err, force = sfive:add("fetch:connected", 1)
--- TODO: race condition: when client disconnects here we won't free up the singleton...
+local lock = locks:new("sfive_locks", { exptime = nil, timeout = 0.001 })
+local ok, err = lock:lock("fetch")
 if not ok then
-   if err == "exists" then
+   if err == "timeout" then
       ngx.exit(ngx.HTTP_SERVICE_UNAVAILABLE)
    else
-      ngx.log(ngx.ERR, "SFive(fetch): failed to set connected flag: " .. err)
+      ngx.log(ngx.ERR, "SFive(fetch): failed to acquire fetch lock: " .. err)
       ngx.exit(ngx.HTTP_INTERNAL_SERVER_ERROR)
    end
 else
-   local ok, err = ngx.on_abort(fetch_cleanup)
-   if not ok then
-      ngx.log(ngx.ERR, "SFive(fetch): failed to register the on_abort callback: ", err)
-      ngx.exit(ngx.HTTP_INTERNAL_SERVER_ERROR)
-   end
-
    ngx.log(ngx.INFO, "SFive(fetch): client connected")
-
-   local sfive_log = ngx.shared.sfive_log
+   local sfive_data = ngx.shared.sfive_data
    while true do
-      logs = sfive_log:get_keys()
+      logs = sfive_data:get_keys()
       for i, k in ipairs(logs) do
-         local ok, err = ngx.say(sfive_log:get(k))
+         local ok, err = ngx.say(sfive_data:get(k))
          if not ok then
-            ngx.log(ngx.ERR, "SFive(fetch): failed to register the on_abort callback: ", err)
+            ngx.log(ngx.ERR, "SFive(fetch): failed to send data set: ", err)
             break
          end
-         sfive_log:delete(k)
+         sfive_data:delete(k)
       end
       ngx.flush()
       ngx.sleep(0.1)
    end
-   fetch_cleenup()
+   ok, err = lock:unlock("fetch")
+   if not ok then
+      ngx.log(ngx.ERR, "SFive(fetch): unlock error: " .. err)
+   end
 end
diff --git a/src/daq/nginx-lua/s5-nginx-init.lua b/src/daq/nginx-lua/s5-nginx-init.lua
index 9d73603..7270e23 100644
--- a/src/daq/nginx-lua/s5-nginx-init.lua
+++ b/src/daq/nginx-lua/s5-nginx-init.lua
@@ -34,22 +34,37 @@
 --
 -- http {
 --   lua_shared_dict sfive 64k;
---   lua_shared_dict sfive_log 64m;
+--   lua_shared_dict sfive_locks 64k;
+--   lua_shared_dict sfive_data 64m;
 --   init_by_lua_file '/path/to/s5-nginx-init.lua';
 -- }
 --
 
 ngx.log(ngx.DEBUG, "SFive: loaded")
+
+locks = require "resty.lock"
+
 local sfive = ngx.shared.sfive
 sfive:flush_all()
 sfive:flush_expired()
-local sfive_log = ngx.shared.sfive_log
-sfive_log:flush_all()
-sfive_log:flush_expired()
+local sfive_data = ngx.shared.sfive_data
+sfive_data:flush_all()
+sfive_data:flush_expired()
 
-local ok, err, force = sfive:set("log:idx", 0)
-if not ok then
-   ngx.log(ngx.ERR, "SFive(init): creating log index counter failed: " .. err)
+-- try to create locks so we get an error on init and not on first usage
+local lock = locks:new("sfive_locks")
+local elapsed, err = lock:lock("test")
+if not elapsed then
+   ngx.log(ngx.ERR, "SFive(init): lock error: " .. err)
 else
-   ngx.log(ngx.INFO, "SFive(init): initialized successfully!")
+   local ok, err, force = sfive:set("log:idx", 0)
+   if not ok then
+      ngx.log(ngx.ERR, "SFive(init): creating log index counter failed: " .. err)
+   else
+      ngx.log(ngx.INFO, "SFive(init): initialized successfully!")
+   end
+   ok, err = lock:unlock("test")
+   if not ok then
+      ngx.log(ngx.ERR, "SFive(init): unlock error: " .. err)
+   end
 end
diff --git a/src/daq/nginx-lua/s5-nginx-log.lua b/src/daq/nginx-lua/s5-nginx-log.lua
index daad0f4..43d2394 100644
--- a/src/daq/nginx-lua/s5-nginx-log.lua
+++ b/src/daq/nginx-lua/s5-nginx-log.lua
@@ -88,8 +88,8 @@ if status == '200' or status == '206' then
       json = json .. '"bytes_sent": ' .. ngx.var.bytes_sent
       json = json .. '}'
 
-      local sfive_log = ngx.shared.sfive_log
-      local ok, err, force = sfive_log:add(idx, json, log_exptime)
+      local sfive_data = ngx.shared.sfive_data
+      local ok, err, force = sfive_data:add(idx, json, log_exptime)
       if not ok then
          ngx.log(ngx.ERR, "SFive(log): adding log line (".. idx .. ") to log store failed: " .. err)
       elseif force then
-- 
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