[LG] Add CacheScope option (#4602)

* add cache option

* app ! to global

* apply reexecute

* add more test and renaming

* revert the schema file

* fix typo

* rename template -> locale

libraries/Microsoft.Bot.Builder.LanguageGeneration/EvaluationOptions.cs

@@ -24,6 +24,27 @@ namespace Microsoft.Bot.Builder.LanguageGeneration
         Markdown,
     }
 
+    /// <summary>
+    /// LG cache scope options.
+    /// </summary>
+    public enum LGCacheScope
+    {
+        /// <summary>
+        /// Global template cache scope.
+        /// </summary>
+        Global,
+
+        /// <summary>
+        /// Only cache result in the same layer of children in template.
+        /// </summary>
+        Local,
+
+        /// <summary>
+        /// Without cache.
+        /// </summary>
+        None
+    }
+
     /// <summary>
     /// Options for evaluating LG templates.
     /// </summary>
@@ -43,6 +64,7 @@ namespace Microsoft.Bot.Builder.LanguageGeneration
             NullSubstitution = null;
             LineBreakStyle = null;
             Locale = null;
+            CacheScope = null;
         }
 
         /// <summary>
@@ -55,6 +77,7 @@ namespace Microsoft.Bot.Builder.LanguageGeneration
             NullSubstitution = opt.NullSubstitution;
             LineBreakStyle = opt.LineBreakStyle;
             Locale = opt.Locale ?? Thread.CurrentThread.CurrentCulture.Name;
+            CacheScope = opt.CacheScope;
         }
 
         /// <summary>
@@ -125,6 +148,14 @@ namespace Microsoft.Bot.Builder.LanguageGeneration
         /// </value>
         public Func<string, object> NullSubstitution { get; set; } = null;
 
+        /// <summary>
+        /// Gets or sets cache scope of the evaluation result.
+        /// </summary>
+        /// <value>
+        /// Cache scope of the evaluation result.
+        /// </value>
+        public LGCacheScope? CacheScope { get; set; } = null;
+
         /// <summary>
         /// Merge a incoming option to current option. If a property in incoming option is not null while it is null in current
         /// option, then the value of this property will be overwritten.

libraries/Microsoft.Bot.Builder.LanguageGeneration/EvaluationTarget.cs

@@ -23,12 +23,12 @@ namespace Microsoft.Bot.Builder.LanguageGeneration
         }
 
         /// <summary>
-        /// Gets or sets the children template that this template has evaluated currently. 
+        /// Gets or sets the children template that this template has evaluated and cached currently. 
         /// </summary>
         /// <value>
         /// The children template that this template has evaluated currently. 
         /// </value>
-        public Dictionary<string, object> EvaluatedChildren { get; set; } = new Dictionary<string, object>();
+        public Dictionary<string, object> CachedEvaluatedChildren { get; set; } = new Dictionary<string, object>();
 
         /// <summary>
         /// Gets or sets template name.

libraries/Microsoft.Bot.Builder.LanguageGeneration/Evaluator.cs

@@ -2,6 +2,7 @@
 // Licensed under the MIT License.
 
 using System;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -23,6 +24,8 @@ namespace Microsoft.Bot.Builder.LanguageGeneration
         internal const string LGType = "lgType";
 
         private const string ReExecuteSuffix = "!";
+
+        private static readonly ConcurrentDictionary<string, object> _cachedResult = new ConcurrentDictionary<string, object>();
         private readonly Stack<EvaluationTarget> _evaluationTargetStack = new Stack<EvaluationTarget>();
         private readonly EvaluationOptions _lgOptions;
 
@@ -85,7 +88,6 @@ namespace Microsoft.Bot.Builder.LanguageGeneration
             }
 
             var templateTarget = new EvaluationTarget(templateName, memory);
-
             var currentEvaluateId = templateTarget.GetId();
 
             if (_evaluationTargetStack.Any(e => e.GetId() == currentEvaluateId))
@@ -93,26 +95,55 @@ namespace Microsoft.Bot.Builder.LanguageGeneration
                 throw new Exception($"{TemplateErrors.LoopDetected} {string.Join(" => ", _evaluationTargetStack.Reverse().Select(e => e.TemplateName))} => {templateName}");
             }
 
-            EvaluationTarget previousEvaluateTarget = null;
-            if (_evaluationTargetStack.Count != 0)
+            object result = null;
+            var hasResult = false;
+            if (!reExecute)
             {
-                previousEvaluateTarget = _evaluationTargetStack.Peek();
-
-                if (!reExecute && previousEvaluateTarget.EvaluatedChildren.ContainsKey(currentEvaluateId))
+                if (_lgOptions.CacheScope == LGCacheScope.Global)
                 {
-                    return previousEvaluateTarget.EvaluatedChildren[currentEvaluateId];
+                    if (_cachedResult.ContainsKey(currentEvaluateId))
+                    {
+                        result = _cachedResult[currentEvaluateId];
+                        hasResult = true;
+                    }
+                }
+                else if (_lgOptions.CacheScope == null || _lgOptions.CacheScope == LGCacheScope.Local)
+                {
+                    EvaluationTarget previousEvaluateTarget = null;
+                    if (_evaluationTargetStack.Count != 0)
+                    {
+                        previousEvaluateTarget = _evaluationTargetStack.Peek();
+
+                        if (previousEvaluateTarget.CachedEvaluatedChildren.ContainsKey(currentEvaluateId))
+                        {
+                            result = previousEvaluateTarget.CachedEvaluatedChildren[currentEvaluateId];
+                            hasResult = true;
+                        }
+                    }
                 }
             }
 
-            // Using a stack to track the evaluation trace
-            _evaluationTargetStack.Push(templateTarget);
-            var result = Visit(TemplateMap[templateName].TemplateBodyParseTree);
-            if (previousEvaluateTarget != null)
+            if (!hasResult)
             {
-                previousEvaluateTarget.EvaluatedChildren[currentEvaluateId] = result;
-            }
+                _evaluationTargetStack.Push(templateTarget);
+                result = Visit(TemplateMap[templateName].TemplateBodyParseTree);
+                _evaluationTargetStack.Pop();
 
-            _evaluationTargetStack.Pop();
+                if (!reExecute)
+                {
+                    if (_lgOptions.CacheScope == LGCacheScope.Global)
+                    {
+                        _cachedResult[currentEvaluateId] = result;
+                    }
+                    else if (_lgOptions.CacheScope == null || _lgOptions.CacheScope == LGCacheScope.Local)
+                    {
+                        if (_evaluationTargetStack.Count > 0)
+                        {
+                            _evaluationTargetStack.Peek().CachedEvaluatedChildren[currentEvaluateId] = result;
+                        }
+                    }
+                }
+            }
 
             return result;
         }

tests/Microsoft.Bot.Builder.LanguageGeneration.Tests/Examples/ReExecute.lg

@@ -1,5 +1,5 @@
 # templateWithSameParams(param)
-- ${listTemplate1(param)} ${listTemplate1!(param)}
+- ${listTemplate1(param)} ${listTemplate1!(param)} ${listTemplate1(param)}
 
 # listTemplate1(param)
 - item1

tests/Microsoft.Bot.Builder.LanguageGeneration.Tests/Examples/TemplateCache.lg

@@ -9,4 +9,11 @@
 - item2
 - item3
 - item4
-- item5
+- item5
+
+
+# globalCache(param)
+- ${subTemplate(param)} ${listTemplate1(param)}
+
+# subTemplate(param)
+- ${listTemplate1(param)}

tests/Microsoft.Bot.Builder.LanguageGeneration.Tests/Microsoft.Bot.Builder.LanguageGeneration.Tests.csproj

@@ -51,13 +51,13 @@
     <None Remove="Examples\NonAdaptiveCardActivity.lg" />
     <None Remove="Examples\StrictModeFalse.lg" />
     <None Remove="Examples\switchcase.lg" />
+    <None Remove="Examples\TemplateCache.lg" />
     <None Remove="Examples\TemplateNameWithDot.lg" />
     <None Remove="Examples\TemplateRef.lg" />
     <None Remove="Examples\Regex.lg" />
     <None Remove="Examples\EvalExpression.lg" />
     <None Remove="Examples\StructuredTemplate.lg" />
     <None Remove="Examples\ConditionExpression.lg" />
-    <None Remove="Examples\EvaluateOnce.lg" />
     <None Remove="Examples\LoopScope.lg" />
     <None Remove="Examples\ExpressionExtract.lg" />
     <None Remove="Examples\StringInterpolation.lg" />
@@ -233,7 +233,7 @@
     <Content Include="Examples\StructuredTemplate.lg">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </Content>
-    <Content Include="Examples\EvaluateOnce.lg">
+    <Content Include="Examples\TemplateCache.lg">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </Content>
     <Content Include="Examples\ReExecute.lg">

tests/Microsoft.Bot.Builder.LanguageGeneration.Tests/TemplatesTest.cs

@@ -1107,9 +1107,9 @@ namespace Microsoft.Bot.Builder.AI.LanguageGeneration.Tests
         }
 
         [Fact]
-        public void TestEvaluateOnce()
+        public void TestTemplateCache()
         {
-            var templates = Templates.ParseFile(GetExampleFilePath("EvaluateOnce.lg"));
+            var templates = Templates.ParseFile(GetExampleFilePath("TemplateCache.lg"));
 
             var evaled = templates.Evaluate("templateWithSameParams", new { param = "ms" });
             Assert.NotNull(evaled);
@@ -1120,6 +1120,13 @@ namespace Microsoft.Bot.Builder.AI.LanguageGeneration.Tests
 
             // may be has different values
             evaled = templates.Evaluate("templateWithDifferentParams", new { param1 = "ms", param2 = "newms" });
+
+            // global cache test
+            evaled = templates.Evaluate("globalCache", new { param = "ms" }, new EvaluationOptions { CacheScope = LGCacheScope.Global });
+
+            resultList = evaled.ToString().Split(" ");
+            Assert.True(resultList.Length == 2);
+            Assert.True(resultList[0] == resultList[1]);
         }
 
         [Fact]
@@ -1129,6 +1136,11 @@ namespace Microsoft.Bot.Builder.AI.LanguageGeneration.Tests
 
             // may be has different values
             var evaled = templates.Evaluate("templateWithSameParams", new { param1 = "ms", param2 = "newms" });
+
+            // the third one should be the same with the first one
+            var resultList = evaled.ToString().Split(" ");
+            Assert.True(resultList.Length == 3);
+            Assert.True(resultList[0] == resultList[2]);
         }
 
         [Fact]