Add ExecCachedLua for managing book keeping around loading/executing cached lua scripts

Author: mythz

lib/tests/ServiceStack.Interfaces.dll

@@ -12,6 +12,7 @@
 
 using System;
 using System.Collections;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
@@ -866,6 +867,29 @@ public string UrnKey(Type type, object id)
 
         #region LUA EVAL
 
+        static readonly ConcurrentDictionary<string, string> CachedLuaSha1Map =
+            new ConcurrentDictionary<string, string>();
+
+        public T ExecCachedLua<T>(string scriptBody, Func<string, T> scriptSha1)
+        {
+            string sha1;
+            if (!CachedLuaSha1Map.TryGetValue(scriptBody, out sha1))
+                CachedLuaSha1Map[scriptBody] = sha1 = LoadLuaScript(scriptBody);
+
+            try
+            {
+                return scriptSha1(sha1);
+            }
+            catch (RedisResponseException ex)
+            {
+                if (!ex.Message.StartsWith("NOSCRIPT"))
+                    throw;
+
+                CachedLuaSha1Map[scriptBody] = sha1 = LoadLuaScript(scriptBody);
+                return scriptSha1(sha1);
+            }
+        }
+
         public RedisText ExecLua(string body, params string[] args)
         {
             var data = base.EvalCommand(body, 0, args.ToMultiByteArray());

src/ServiceStack.Redis/RedisClient.cs

@@ -528,7 +528,10 @@ protected T SendReceive<T>(byte[][] cmdWithBinaryArgs,
                 {
                     var retryableEx = outerEx as RedisRetryableException;
                     if (retryableEx == null && outerEx is RedisException)
+                    {
+                        ResetSendBuffer();
                         throw;
+                    }
 
                     var ex = retryableEx ?? GetRetryableException(outerEx);
                     if (ex == null)

src/ServiceStack.Redis/RedisNativeClient_Utils.cs

@@ -0,0 +1,84 @@
+using NUnit.Framework;
+using ServiceStack.Text;
+
+namespace ServiceStack.Redis.Tests
+{
+    [TestFixture]
+    public class LuaCachedScripts
+    {
+        private const string LuaScript = @"
+local limit = tonumber(ARGV[2])
+local pattern = ARGV[1]
+local cursor = 0
+local len = 0
+local results = {}
+
+repeat
+    local r = redis.call('scan', cursor, 'MATCH', pattern, 'COUNT', limit)
+    cursor = tonumber(r[1])
+    for k,v in ipairs(r[2]) do
+        table.insert(results, v)
+        len = len + 1
+        if len == limit then break end
+    end
+until cursor == 0 or len == limit
+
+return results
+";
+
+        private static void AddTestKeys(RedisClient redis, int count)
+        {
+            count.Times(i =>
+                redis.SetValue("key:" + i, "value:" + i));
+        }
+
+        [Test]
+        public void Can_call_repeated_scans_in_LUA()
+        {
+            using (var redis = new RedisClient())
+            {
+                AddTestKeys(redis, 20);
+
+                var r = redis.ExecLua(LuaScript, "key:*", "10");
+                Assert.That(r.Children.Count, Is.EqualTo(10));
+
+                r = redis.ExecLua(LuaScript, "key:*", "40");
+                Assert.That(r.Children.Count, Is.EqualTo(20));
+            }
+        }
+
+        [Test]
+        public void Can_call_Cached_Lua()
+        {
+            using (var redis = new RedisClient())
+            {
+                AddTestKeys(redis, 20);
+
+                var r = redis.ExecCachedLua(LuaScript, sha1 =>
+                    redis.ExecLuaSha(sha1, "key:*", "10"));
+                Assert.That(r.Children.Count, Is.EqualTo(10));
+
+                r = redis.ExecCachedLua(LuaScript, sha1 =>
+                    redis.ExecLuaSha(sha1, "key:*", "10"));
+                Assert.That(r.Children.Count, Is.EqualTo(10));
+            }
+        }
+
+        [Test]
+        public void Can_call_Cached_Lua_even_after_script_is_flushed()
+        {
+            using (var redis = new RedisClient())
+            {
+                var r = redis.ExecCachedLua(LuaScript, sha1 =>
+                    redis.ExecLuaSha(sha1, "key:*", "10"));
+                Assert.That(r.Children.Count, Is.EqualTo(10));
+
+                redis.ScriptFlush();
+
+                r = redis.ExecCachedLua(LuaScript, sha1 =>
+                    redis.ExecLuaSha(sha1, "key:*", "10"));
+                Assert.That(r.Children.Count, Is.EqualTo(10));
+            }
+        }
+    }
+}

tests/ServiceStack.Redis.Tests/LuaCachedScripts.cs

@@ -183,6 +183,7 @@
     <Compile Include="AdhocClientTests.cs" />
     <Compile Include="ConfigTests.cs" />
     <Compile Include="CustomCommandTests.cs" />
+    <Compile Include="LuaCachedScripts.cs" />
     <Compile Include="Examples\TestData.cs" />
     <Compile Include="Issues\RedisCharacterizationTests.cs" />
     <Compile Include="RedisBatchTests.cs" />