From b23abfa781413cd764d5083f1fa593766b8a82d7 Mon Sep 17 00:00:00 2001
From: Stuart Tettemer <stu@elastic.co>
Date: Tue, 2 Mar 2021 16:08:54 -0600
Subject: [PATCH 1/2] Script: no compile rate limit for ingest templates

Remove the compilation rate limit for ingest templates.

Creates a new context, `ingest_template`, with an unlimited
compilation rate limit.

The `template` context is used in many places so it cannot be
exempted from rate limits.

Fixes: #64595
---
 .../elasticsearch/script/mustache/MustacheScriptEngine.java | 2 +-
 .../src/main/java/org/elasticsearch/ingest/ValueSource.java | 2 +-
 .../main/java/org/elasticsearch/script/ScriptModule.java    | 1 +
 .../main/java/org/elasticsearch/script/TemplateScript.java  | 6 ++++++
 4 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/modules/lang-mustache/src/main/java/org/elasticsearch/script/mustache/MustacheScriptEngine.java b/modules/lang-mustache/src/main/java/org/elasticsearch/script/mustache/MustacheScriptEngine.java
index 202e16c2415a9..659d385ec2b47 100644
--- a/modules/lang-mustache/src/main/java/org/elasticsearch/script/mustache/MustacheScriptEngine.java
+++ b/modules/lang-mustache/src/main/java/org/elasticsearch/script/mustache/MustacheScriptEngine.java
@@ -75,7 +75,7 @@ public <T> T compile(
 
     @Override
     public Set<ScriptContext<?>> getSupportedContexts() {
-        return Set.of(TemplateScript.CONTEXT);
+        return Set.of(TemplateScript.CONTEXT, TemplateScript.INGEST_CONTEXT);
     }
 
     private CustomMustacheFactory createMustacheFactory(Map<String, String> options) {
diff --git a/server/src/main/java/org/elasticsearch/ingest/ValueSource.java b/server/src/main/java/org/elasticsearch/ingest/ValueSource.java
index be02fde2431ca..2272c3d4136a9 100644
--- a/server/src/main/java/org/elasticsearch/ingest/ValueSource.java
+++ b/server/src/main/java/org/elasticsearch/ingest/ValueSource.java
@@ -69,7 +69,7 @@ static ValueSource wrap(Object value, ScriptService scriptService, Map<String, S
             // modified if templating is not available
             if (scriptService.isLangSupported(DEFAULT_TEMPLATE_LANG) && ((String) value).contains("{{")) {
                 Script script = new Script(ScriptType.INLINE, DEFAULT_TEMPLATE_LANG, (String) value, scriptOptions, Map.of());
-                return new TemplatedValue(scriptService.compile(script, TemplateScript.CONTEXT));
+                return new TemplatedValue(scriptService.compile(script, TemplateScript.INGEST_CONTEXT));
             } else {
                 return new ObjectValue(value);
             }
diff --git a/server/src/main/java/org/elasticsearch/script/ScriptModule.java b/server/src/main/java/org/elasticsearch/script/ScriptModule.java
index 8485ecd722e30..1c1094123470f 100644
--- a/server/src/main/java/org/elasticsearch/script/ScriptModule.java
+++ b/server/src/main/java/org/elasticsearch/script/ScriptModule.java
@@ -53,6 +53,7 @@ public class ScriptModule {
             SimilarityScript.CONTEXT,
             SimilarityWeightScript.CONTEXT,
             TemplateScript.CONTEXT,
+            TemplateScript.INGEST_CONTEXT,
             MovingFunctionScript.CONTEXT,
             ScriptedMetricAggContexts.InitScript.CONTEXT,
             ScriptedMetricAggContexts.MapScript.CONTEXT,
diff --git a/server/src/main/java/org/elasticsearch/script/TemplateScript.java b/server/src/main/java/org/elasticsearch/script/TemplateScript.java
index a22ca0abc58bc..756d8cf8238d2 100644
--- a/server/src/main/java/org/elasticsearch/script/TemplateScript.java
+++ b/server/src/main/java/org/elasticsearch/script/TemplateScript.java
@@ -8,6 +8,8 @@
 
 package org.elasticsearch.script;
 
+import org.elasticsearch.common.unit.TimeValue;
+
 import java.util.Map;
 
 /**
@@ -35,4 +37,8 @@ public interface Factory {
     }
 
     public static final ScriptContext<Factory> CONTEXT = new ScriptContext<>("template", Factory.class);
+
+    // Remove compilation rate limit for ingest
+    public static final ScriptContext<Factory> INGEST_CONTEXT = new ScriptContext<>("ingest_template", Factory.class,
+            200, TimeValue.timeValueMillis(0), ScriptCache.UNLIMITED_COMPILATION_RATE.asTuple());
 }

From ad956d0277e0ccd64ad38472d3e887338eb7e993 Mon Sep 17 00:00:00 2001
From: Stuart Tettemer <stu@elastic.co>
Date: Wed, 3 Mar 2021 14:01:36 -0600
Subject: [PATCH 2/2] Scripting: expand INGEST_CONTEXT comment

---
 .../main/java/org/elasticsearch/script/TemplateScript.java    | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/server/src/main/java/org/elasticsearch/script/TemplateScript.java b/server/src/main/java/org/elasticsearch/script/TemplateScript.java
index 756d8cf8238d2..6738df2536689 100644
--- a/server/src/main/java/org/elasticsearch/script/TemplateScript.java
+++ b/server/src/main/java/org/elasticsearch/script/TemplateScript.java
@@ -38,7 +38,9 @@ public interface Factory {
 
     public static final ScriptContext<Factory> CONTEXT = new ScriptContext<>("template", Factory.class);
 
-    // Remove compilation rate limit for ingest
+    // Remove compilation rate limit for ingest.  Ingest pipelines may use many mustache templates, triggering compilation
+    // rate limiting.  MustacheScriptEngine explicitly checks for TemplateScript.  Rather than complicating the implementation there by
+    // creating a new Script class (as would be customary), this context is used to avoid the default rate limit.
     public static final ScriptContext<Factory> INGEST_CONTEXT = new ScriptContext<>("ingest_template", Factory.class,
             200, TimeValue.timeValueMillis(0), ScriptCache.UNLIMITED_COMPILATION_RATE.asTuple());
 }