change(balancer) new randomization setup of the balancer

README.md

@@ -35,6 +35,12 @@ use the `rbusted` script.
 History
 =======
 
+### 0.6.1 (28-Jul-2017) Randomization adjusted
+
+- Change: use a different randomizer for the ring-balancer to predictably
+  recreate the balancer in the exact same state (adds the `lrandom` library as
+  a new dependency)
+
 ### 0.6.0 (14-Jun-2017) Rewritten resolver core to resolve async
 
 - Added: resolution will be done async whenever possible. For this to work a new

docs/index.html

@@ -74,7 +74,7 @@ <h2>Topics</h2>
 </div> <!-- id="main" -->
 <div id="about">
 <i>generated by <a href="http://github.com/stevedonovan/LDoc">LDoc 1.4.6</a></i>
-<i style="float:right;">Last updated 2017-06-15 16:36:27 </i>
+<i style="float:right;">Last updated 2017-07-28 21:55:16 </i>
 </div> <!-- id="about" -->
 </div> <!-- id="container" -->
 </body>

docs/modules/resty.dns.balancer.html

@@ -283,10 +283,7 @@ <h3>Returns:</h3>
     will have to be moved between targets. A value of 50 to 200 slots per entry
     seems about right.</li>
     <li><code>order</code> (optional) if given, a list of random numbers, size <code>wheelSize</code>, used to
-    randomize the wheel. This entry is solely to support multiple servers with
-    the same consistency, as it allows to use the same randomization on each
-    server, and hence the same slot assignment. Duplicates are not allowed in
-    the list.</li>
+    randomize the wheel. Duplicates are not allowed in the list.</li>
     <li><code>dns</code> (required) a configured <a href="../modules/resty.dns.client.html">dns.client</a> object for querying the dns server.</li>
     <li><code>requery</code> (optional) interval of requerying the dns server for previously
     failed queries. Defaults to 1 if omitted (in seconds)</li>
@@ -388,7 +385,7 @@ <h2 class="section-header "><a name="Fields"></a>Fields</h2>
 </div> <!-- id="main" -->
 <div id="about">
 <i>generated by <a href="http://github.com/stevedonovan/LDoc">LDoc 1.4.6</a></i>
-<i style="float:right;">Last updated 2017-06-15 16:36:27 </i>
+<i style="float:right;">Last updated 2017-07-28 21:55:16 </i>
 </div> <!-- id="about" -->
 </div> <!-- id="container" -->
 </body>

docs/modules/resty.dns.client.html

@@ -431,7 +431,7 @@ <h3>Returns:</h3>
 </div> <!-- id="main" -->
 <div id="about">
 <i>generated by <a href="http://github.com/stevedonovan/LDoc">LDoc 1.4.6</a></i>
-<i style="float:right;">Last updated 2017-06-15 16:36:27 </i>
+<i style="float:right;">Last updated 2017-07-28 21:55:16 </i>
 </div> <!-- id="about" -->
 </div> <!-- id="container" -->
 </body>

docs/modules/resty.dns.utils.html

@@ -480,7 +480,7 @@ <h3>Returns:</h3>
 </div> <!-- id="main" -->
 <div id="about">
 <i>generated by <a href="http://github.com/stevedonovan/LDoc">LDoc 1.4.6</a></i>
-<i style="float:right;">Last updated 2017-06-15 16:36:27 </i>
+<i style="float:right;">Last updated 2017-07-28 21:55:16 </i>
 </div> <!-- id="about" -->
 </div> <!-- id="container" -->
 </body>

docs/topics/readme.md.html

@@ -82,6 +82,14 @@ <h1>Testing</h1>
 
 <h1>History</h1>
 
+<h3>0.6.1 (28-Jul-2017) Randomization adjusted</h3>
+
+<ul>
+    <li>Change: use a different randomizer for the ring-balancer to predictably
+    recreate the balancer in the exact same state (adds the <code>lrandom</code> library as
+    a new dependency)</li>
+</ul>
+
 <h3>0.6.0 (14-Jun-2017) Rewritten resolver core to resolve async</h3>
 
 <ul>
@@ -188,7 +196,7 @@ <h3>0.1 (09-Sep-2016) Initial released version</h3>
 </div> <!-- id="main" -->
 <div id="about">
 <i>generated by <a href="http://github.com/stevedonovan/LDoc">LDoc 1.4.6</a></i>
-<i style="float:right;">Last updated 2017-06-15 16:36:27 </i>
+<i style="float:right;">Last updated 2017-07-28 21:55:16 </i>
 </div> <!-- id="about" -->
 </div> <!-- id="container" -->
 </body>

lua-resty-dns-client-0.6.0-1.rockspec → lua-resty-dns-client-0.6.1-1.rockspec

@@ -1,8 +1,8 @@
 package = "lua-resty-dns-client"
-version = "0.6.0-1"
+version = "0.6.1-1"
 source = {
-  url = "https://github.com/Mashape/lua-resty-dns-client/archive/0.6.0.tar.gz",
-  dir = "lua-resty-dns-client-0.6.0"
+  url = "https://github.com/Mashape/lua-resty-dns-client/archive/0.6.1.tar.gz",
+  dir = "lua-resty-dns-client-0.6.1"
 }
 description = {
   summary = "DNS library",
@@ -16,6 +16,7 @@ description = {
 dependencies = {
   "lua >= 5.1, < 5.4",
   "penlight > 1.1, < 2.0",
+  "lrandom",
 }
 build = {
   type = "builtin",

src/resty/dns/balancer.lua

@@ -42,14 +42,14 @@ local REQUERY_INTERVAL = 1  -- Interval for requerying failed dns queries
 local bit = require "bit"
 local dns = require "resty.dns.client"
 local utils = require "resty.dns.utils"
+local lrandom = require "random"
 local empty = setmetatable({}, 
   {__newindex = function() error("The 'empty' table is read-only") end})
 
 local time = ngx.now
 local table_sort = table.sort
 local table_remove = table.remove
 local math_floor = math.floor
-local math_random = math.random
 local string_sub = string.sub
 local ngx_md5 = ngx.md5_bin
 local timer_at = ngx.timer.at
@@ -888,10 +888,7 @@ end
 -- will have to be moved between targets. A value of 50 to 200 slots per entry 
 -- seems about right.
 -- - `order` (optional) if given, a list of random numbers, size `wheelSize`, used to 
--- randomize the wheel. This entry is solely to support multiple servers with 
--- the same consistency, as it allows to use the same randomization on each
--- server, and hence the same slot assignment. Duplicates are not allowed in
--- the list.
+-- randomize the wheel. Duplicates are not allowed in the list.
 -- - `dns` (required) a configured `dns.client` object for querying the dns server.
 -- - `requery` (optional) interval of requerying the dns server for previously 
 -- failed queries. Defaults to 1 if omitted (in seconds)
@@ -946,15 +943,19 @@ _M.new = function(opts)
   local slotList = self.unassignedSlots
   local duplicateCheck = {}
   local empty = {}
+  -- create a new randomizer with just any seed, we do not care about
+  -- uniqueness, only about distribution, and repeatability, each orderlist
+  -- must be identical!
+  local randomizer = lrandom.new(158841259)
   for i = 1, self.wheelSize do
 
     local slot = {}
-    local order = (opts.order or empty)[i] or math_random()
+    local order = (opts.order or empty)[i] or randomizer()
     while duplicateCheck[order] do  -- no duplicates allowed! order must be deterministic!
       if (opts.order or empty)[i] then -- it was a user provided value, so error out
         error("the 'order' list contains duplicates")
       end
-      order = math_random()
+      order = randomizer()
     end
     duplicateCheck[order] = true
     slot.order = order           -- the order in the slot wheel