Script: Opt-out system contexts from script compilation rate limit (#…

…79459)

System script contexts can now opt-out of compilation rate limiting using a flag rather than a sentinel rate limit value.

Duplicated defaults for system contexts have been coalesced.

Refs: #62899

server/src/main/java/org/elasticsearch/script/AbstractFieldScript.java

@@ -52,7 +52,7 @@ static <F> ScriptContext<F> newContext(String name, Class<F> factoryClass) {
              * source of runaway script compilations. We think folks will
              * mostly reuse scripts though.
              */
-            ScriptCache.UNLIMITED_COMPILATION_RATE.asTuple(),
+            false,
             /*
              * Disable runtime fields scripts from being allowed
              * to be stored as part of the script meta data.

server/src/main/java/org/elasticsearch/script/IngestConditionalScript.java

@@ -21,7 +21,7 @@ public abstract class IngestConditionalScript {
 
     /** The context used to compile {@link IngestConditionalScript} factories. */
     public static final ScriptContext<Factory> CONTEXT = new ScriptContext<>("processor_conditional", Factory.class,
-        200, TimeValue.timeValueMillis(0), ScriptCache.UNLIMITED_COMPILATION_RATE.asTuple(), true);
+        200, TimeValue.timeValueMillis(0), false, true);
 
     /** The generic runtime parameters for the script. */
     private final Map<String, Object> params;

server/src/main/java/org/elasticsearch/script/IngestScript.java

@@ -22,7 +22,7 @@ public abstract class IngestScript {
 
     /** The context used to compile {@link IngestScript} factories. */
     public static final ScriptContext<Factory> CONTEXT = new ScriptContext<>("ingest", Factory.class,
-        200, TimeValue.timeValueMillis(0), ScriptCache.UNLIMITED_COMPILATION_RATE.asTuple(), true);
+        200, TimeValue.timeValueMillis(0), false, true);
 
     /** The generic runtime parameters for the script. */
     private final Map<String, Object> params;

server/src/main/java/org/elasticsearch/script/ScriptCache.java

@@ -44,12 +44,7 @@ public class ScriptCache {
     private final double compilesAllowedPerNano;
     private final String contextRateSetting;
 
-    ScriptCache(
-            int cacheMaxSize,
-            TimeValue cacheExpire,
-            CompilationRate maxCompilationRate,
-            String contextRateSetting
-    ) {
+    ScriptCache(int cacheMaxSize, TimeValue cacheExpire, CompilationRate maxCompilationRate, String contextRateSetting) {
         this.cacheSize = cacheMaxSize;
         this.cacheExpire = cacheExpire;
         this.contextRateSetting = contextRateSetting;
@@ -94,8 +89,10 @@ <FactoryType> FactoryType compile(
                     logger.trace("context [{}]: compiling script, type: [{}], lang: [{}], options: [{}]", context.name, type,
                         lang, options);
                 }
-                // Check whether too many compilations have happened
-                checkCompilationLimit();
+                if (context.compilationRateLimited) {
+                    // Check whether too many compilations have happened
+                    checkCompilationLimit();
+                }
                 Object compiledScript = scriptEngine.compile(id, idOrCode, context, options);
                 // Since the cache key is the script content itself we don't need to
                 // invalidate/check the cache if an indexed script changes.

server/src/main/java/org/elasticsearch/script/ScriptCacheStats.java

@@ -21,7 +21,7 @@
 import java.util.Objects;
 import java.util.stream.Collectors;
 
-// This class is deprecated in favor of ScriptStats and ScriptContextStats.  It is removed in 8.
+// This class is deprecated in favor of ScriptStats and ScriptContextStats
 public class ScriptCacheStats implements Writeable, ToXContentFragment {
     private final Map<String, ScriptStats> context;
     private final ScriptStats general;

server/src/main/java/org/elasticsearch/script/ScriptContext.java

@@ -47,6 +47,8 @@
  * be {@code boolean needs_score()}.
  */
 public final class ScriptContext<FactoryType> {
+    /** The default compilation rate limit for contexts with compilation rate limiting enabled */
+    public static final Tuple<Integer, TimeValue> DEFAULT_COMPILATION_RATE_LIMIT = new Tuple<>(150, TimeValue.timeValueMinutes(5));
 
     /** A unique identifier for this context. */
     public final String name;
@@ -66,15 +68,15 @@ public final class ScriptContext<FactoryType> {
     /** The default expiration of a script in the cache for the context, if not overridden */
     public final TimeValue cacheExpireDefault;
 
-    /** The default max compilation rate for scripts in this context.  Script compilation is throttled if this is exceeded */
-    public final Tuple<Integer, TimeValue> maxCompilationRateDefault;
+    /** Is compilation rate limiting enabled for this context? */
+    public final boolean compilationRateLimited;
 
     /** Determines if the script can be stored as part of the cluster state. */
     public final boolean allowStoredScript;
 
     /** Construct a context with the related instance and compiled classes with caller provided cache defaults */
     public ScriptContext(String name, Class<FactoryType> factoryClazz, int cacheSizeDefault, TimeValue cacheExpireDefault,
-                        Tuple<Integer, TimeValue> maxCompilationRateDefault, boolean allowStoredScript) {
+                         boolean compilationRateLimited, boolean allowStoredScript) {
         this.name = name;
         this.factoryClazz = factoryClazz;
         Method newInstanceMethod = findMethod("FactoryType", factoryClazz, "newInstance");
@@ -98,15 +100,15 @@ public ScriptContext(String name, Class<FactoryType> factoryClazz, int cacheSize
 
         this.cacheSizeDefault = cacheSizeDefault;
         this.cacheExpireDefault = cacheExpireDefault;
-        this.maxCompilationRateDefault = maxCompilationRateDefault;
+        this.compilationRateLimited = compilationRateLimited;
         this.allowStoredScript = allowStoredScript;
     }
 
     /** Construct a context with the related instance and compiled classes with defaults for cacheSizeDefault, cacheExpireDefault and
-     *  maxCompilationRateDefault and allow scripts of this context to be stored scripts */
+     *  compilationRateLimited and allow scripts of this context to be stored scripts */
     public ScriptContext(String name, Class<FactoryType> factoryClazz) {
         // cache size default, cache expire default, max compilation rate are defaults from ScriptService.
-        this(name, factoryClazz, 100, TimeValue.timeValueMillis(0), new Tuple<>(75, TimeValue.timeValueMinutes(5)), true);
+        this(name, factoryClazz, 100, TimeValue.timeValueMillis(0), true, true);
     }
 
     /** Returns a method with the given name, or throws an exception if multiple are found. */

server/src/main/java/org/elasticsearch/script/ScriptService.java

@@ -231,7 +231,7 @@ void registerClusterSettingsListeners(ClusterSettings clusterSettings) {
 
         // Handle all settings for context and general caches, this flips between general and context caches.
         clusterSettings.addSettingsUpdateConsumer(
-            (settings) -> setCacheHolder(settings),
+            this::setCacheHolder,
             Arrays.asList(SCRIPT_GENERAL_MAX_COMPILATIONS_RATE_SETTING,
                           SCRIPT_GENERAL_CACHE_EXPIRE_SETTING,
                           SCRIPT_GENERAL_CACHE_SIZE_SETTING,
@@ -565,8 +565,9 @@ void setCacheHolder(Settings settings) {
         } else if (current.general == null) {
             // Flipping to general
             cacheHolder.set(generalCacheHolder(settings));
-        } else if (current.general.rate.equals(SCRIPT_GENERAL_MAX_COMPILATIONS_RATE_SETTING.get(settings)) == false) {
-            // General compilation rate changed, that setting is the only dynamically updated general setting
+        } else if (current.general.rate.equals(SCRIPT_GENERAL_MAX_COMPILATIONS_RATE_SETTING.get(settings)) == false ||
+                   current.general.cacheExpire.equals(SCRIPT_GENERAL_CACHE_EXPIRE_SETTING.get(settings)) == false ||
+                   current.general.cacheSize != SCRIPT_GENERAL_CACHE_SIZE_SETTING.get(settings)) {
             cacheHolder.set(generalCacheHolder(settings));
         }
     }
@@ -592,13 +593,15 @@ ScriptCache contextCache(Settings settings, ScriptContext<?> context) {
 
         Setting<ScriptCache.CompilationRate> rateSetting =
             SCRIPT_MAX_COMPILATIONS_RATE_SETTING.getConcreteSettingForNamespace(context.name);
-        ScriptCache.CompilationRate rate = null;
-        if (SCRIPT_DISABLE_MAX_COMPILATIONS_RATE_SETTING.get(settings) || compilationLimitsEnabled() == false) {
+        ScriptCache.CompilationRate rate;
+        if (SCRIPT_DISABLE_MAX_COMPILATIONS_RATE_SETTING.get(settings)
+                || compilationLimitsEnabled() == false
+                || context.compilationRateLimited == false) {
             rate = SCRIPT_COMPILATION_RATE_ZERO;
         } else if (rateSetting.existsOrFallbackExists(settings)) {
             rate = rateSetting.get(settings);
         } else {
-            rate = new ScriptCache.CompilationRate(context.maxCompilationRateDefault);
+            rate = new ScriptCache.CompilationRate(ScriptContext.DEFAULT_COMPILATION_RATE_LIMIT);
         }
 
         return new ScriptCache(cacheSize, cacheExpire, rate, rateSetting.getKey());

server/src/main/java/org/elasticsearch/script/TemplateScript.java

@@ -42,5 +42,5 @@ public interface Factory {
     // 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(), true);
+            200, TimeValue.timeValueMillis(0), false, true);
 }

server/src/test/java/org/elasticsearch/script/ScriptCacheTests.java

@@ -8,14 +8,54 @@
 package org.elasticsearch.script;
 
 import org.elasticsearch.common.breaker.CircuitBreakingException;
+import org.elasticsearch.common.settings.Setting;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.core.TimeValue;
 import org.elasticsearch.test.ESTestCase;
 
+import java.util.stream.Collectors;
+
 public class ScriptCacheTests extends ESTestCase {
     // even though circuit breaking is allowed to be configured per minute, we actually weigh this over five minutes
     // simply by multiplying by five, so even setting it to one, requires five compilations to break
     public void testCompilationCircuitBreaking() throws Exception {
+        String context = randomFrom(
+            ScriptModule.CORE_CONTEXTS.values().stream().filter(
+                c -> c.compilationRateLimited
+            ).collect(Collectors.toList())
+        ).name;
+        final TimeValue expire = ScriptService.SCRIPT_CACHE_EXPIRE_SETTING.getConcreteSettingForNamespace(context).get(Settings.EMPTY);
+        final Integer size = ScriptService.SCRIPT_CACHE_SIZE_SETTING.getConcreteSettingForNamespace(context).get(Settings.EMPTY);
+        Setting<ScriptCache.CompilationRate> rateSetting =
+            ScriptService.SCRIPT_MAX_COMPILATIONS_RATE_SETTING.getConcreteSettingForNamespace(context);
+        ScriptCache.CompilationRate rate =
+            ScriptService.SCRIPT_MAX_COMPILATIONS_RATE_SETTING.getConcreteSettingForNamespace(context).get(Settings.EMPTY);
+        String rateSettingName = rateSetting.getKey();
+        ScriptCache cache = new ScriptCache(size, expire,
+            new ScriptCache.CompilationRate(1, TimeValue.timeValueMinutes(1)), rateSettingName);
+        cache.checkCompilationLimit(); // should pass
+        expectThrows(CircuitBreakingException.class, cache::checkCompilationLimit);
+        cache = new ScriptCache(size, expire, new ScriptCache.CompilationRate(2, TimeValue.timeValueMinutes(1)), rateSettingName);
+        cache.checkCompilationLimit(); // should pass
+        cache.checkCompilationLimit(); // should pass
+        expectThrows(CircuitBreakingException.class, cache::checkCompilationLimit);
+        int count = randomIntBetween(5, 50);
+        cache = new ScriptCache(size, expire, new ScriptCache.CompilationRate(count, TimeValue.timeValueMinutes(1)), rateSettingName);
+        for (int i = 0; i < count; i++) {
+            cache.checkCompilationLimit(); // should pass
+        }
+        expectThrows(CircuitBreakingException.class, cache::checkCompilationLimit);
+        cache = new ScriptCache(size, expire, new ScriptCache.CompilationRate(0, TimeValue.timeValueMinutes(1)), rateSettingName);
+        expectThrows(CircuitBreakingException.class, cache::checkCompilationLimit);
+        cache = new ScriptCache(size, expire,
+                                new ScriptCache.CompilationRate(Integer.MAX_VALUE, TimeValue.timeValueMinutes(1)), rateSettingName);
+        int largeLimit = randomIntBetween(1000, 10000);
+        for (int i = 0; i < largeLimit; i++) {
+            cache.checkCompilationLimit();
+        }
+    }
+
+    public void testGeneralCompilationCircuitBreaking() throws Exception {
         final TimeValue expire = ScriptService.SCRIPT_GENERAL_CACHE_EXPIRE_SETTING.get(Settings.EMPTY);
         final Integer size = ScriptService.SCRIPT_GENERAL_CACHE_SIZE_SETTING.get(Settings.EMPTY);
         String settingName = ScriptService.SCRIPT_GENERAL_MAX_COMPILATIONS_RATE_SETTING.getKey();
@@ -35,14 +75,33 @@ public void testCompilationCircuitBreaking() throws Exception {
         cache = new ScriptCache(size, expire, new ScriptCache.CompilationRate(0, TimeValue.timeValueMinutes(1)), settingName);
         expectThrows(CircuitBreakingException.class, cache::checkCompilationLimit);
         cache = new ScriptCache(size, expire,
-                                new ScriptCache.CompilationRate(Integer.MAX_VALUE, TimeValue.timeValueMinutes(1)), settingName);
+            new ScriptCache.CompilationRate(Integer.MAX_VALUE, TimeValue.timeValueMinutes(1)), settingName);
         int largeLimit = randomIntBetween(1000, 10000);
         for (int i = 0; i < largeLimit; i++) {
             cache.checkCompilationLimit();
         }
     }
 
     public void testUnlimitedCompilationRate() {
+        String context = randomFrom(
+            ScriptModule.CORE_CONTEXTS.values().stream().filter(
+                c -> c.compilationRateLimited
+            ).collect(Collectors.toList())
+        ).name;
+        final Integer size = ScriptService.SCRIPT_CACHE_SIZE_SETTING.getConcreteSettingForNamespace(context).get(Settings.EMPTY);
+        final TimeValue expire = ScriptService.SCRIPT_CACHE_EXPIRE_SETTING.getConcreteSettingForNamespace(context).get(Settings.EMPTY);
+        String settingName = ScriptService.SCRIPT_MAX_COMPILATIONS_RATE_SETTING.getConcreteSettingForNamespace(context).getKey();
+        ScriptCache cache = new ScriptCache(size, expire, ScriptCache.UNLIMITED_COMPILATION_RATE, settingName);
+        ScriptCache.TokenBucketState initialState = cache.tokenBucketState.get();
+        for(int i=0; i < 3000; i++) {
+            cache.checkCompilationLimit();
+            ScriptCache.TokenBucketState currentState = cache.tokenBucketState.get();
+            assertEquals(initialState.lastInlineCompileTime, currentState.lastInlineCompileTime);
+            assertEquals(initialState.availableTokens, currentState.availableTokens, 0.0); // delta of 0.0 because it should never change
+        }
+    }
+
+    public void testGeneralUnlimitedCompilationRate() {
         final Integer size = ScriptService.SCRIPT_GENERAL_CACHE_SIZE_SETTING.get(Settings.EMPTY);
         final TimeValue expire = ScriptService.SCRIPT_GENERAL_CACHE_EXPIRE_SETTING.get(Settings.EMPTY);
         String settingName = ScriptService.SCRIPT_GENERAL_MAX_COMPILATIONS_RATE_SETTING.getKey();