feat: skip regex resource matching when exact match exists (default disabled, configurable)(#3565)

* Simple rules should have higher priority than regular expression rules

* Add optional switch to skip regex matching when simple rules already match, default: false, keeps backward compatibility.

* fix RuleManagerTest unit test failure

sentinel-core/src/main/java/com/alibaba/csp/sentinel/config/SentinelConfig.java

@@ -61,6 +61,7 @@ public final class SentinelConfig {
     public static final String STATISTIC_MAX_RT = "csp.sentinel.statistic.max.rt";
     public static final String SPI_CLASSLOADER = "csp.sentinel.spi.classloader";
     public static final String METRIC_FLUSH_INTERVAL = "csp.sentinel.metric.flush.interval";
+    public static final String SKIP_REGEX_IF_SIMPLE_RULE_MATCHED_KEY = "csp.sentinel.rule.regex.skip.if.simple.matched";
 
     public static final String DEFAULT_CHARSET = "UTF-8";
     public static final long DEFAULT_SINGLE_METRIC_FILE_SIZE = 1024 * 1024 * 50;
@@ -68,6 +69,7 @@ public final class SentinelConfig {
     public static final int DEFAULT_COLD_FACTOR = 3;
     public static final int DEFAULT_STATISTIC_MAX_RT = 5000;
     public static final long DEFAULT_METRIC_FLUSH_INTERVAL = 1L;
+    public static final String DEFAULT_SKIP_REGEX_IF_SIMPLE_RULE_MATCHED = "false";
 
     static {
         try {
@@ -106,6 +108,7 @@ public final class SentinelConfig {
         setConfig(COLD_FACTOR, String.valueOf(DEFAULT_COLD_FACTOR));
         setConfig(STATISTIC_MAX_RT, String.valueOf(DEFAULT_STATISTIC_MAX_RT));
         setConfig(METRIC_FLUSH_INTERVAL, String.valueOf(DEFAULT_METRIC_FLUSH_INTERVAL));
+        setConfig(SKIP_REGEX_IF_SIMPLE_RULE_MATCHED_KEY, DEFAULT_SKIP_REGEX_IF_SIMPLE_RULE_MATCHED);
     }
 
     private static void loadProps() {
@@ -341,5 +344,13 @@ public final class SentinelConfig {
         return CLASSLOADER_CONTEXT.equalsIgnoreCase(classloaderConf);
     }
 
+    /**
+     * Return whether to skip regex matching when simple rules already matched.
+     * Default: false (keeps backward compatibility).
+     */
+    public static boolean shouldSkipRegexIfSimpleRuleMatched() {
+        return Boolean.parseBoolean(getConfig(SKIP_REGEX_IF_SIMPLE_RULE_MATCHED_KEY));
+    }
+
     private SentinelConfig() {}
 }

sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/RuleManager.java

@@ -17,6 +17,7 @@ package com.alibaba.csp.sentinel.slots.block;
 
 import com.alibaba.csp.sentinel.util.function.Function;
 import com.alibaba.csp.sentinel.util.function.Predicate;
+import com.alibaba.csp.sentinel.config.SentinelConfig;
 
 import java.util.*;
 import java.util.regex.Pattern;
@@ -86,7 +87,7 @@ public class RuleManager<R> {
      */
     public List<R> getRules(String resource) {
         List<R> result = new ArrayList<>(simpleRules.getOrDefault(resource, Collections.emptyList()));
-        if (regexRules.isEmpty()) {
+        if (regexRules.isEmpty() || (SentinelConfig.shouldSkipRegexIfSimpleRuleMatched() && !result.isEmpty())) {
             return result;
         }
         if (regexCacheRules.containsKey(resource)) {

sentinel-core/src/test/java/com/alibaba/csp/sentinel/config/SentinelConfigTest.java

@@ -26,6 +26,7 @@ public class SentinelConfigTest {
         assertEquals(SentinelConfig.DEFAULT_TOTAL_METRIC_FILE_COUNT, SentinelConfig.totalMetricFileCount());
         assertEquals(SentinelConfig.DEFAULT_COLD_FACTOR, SentinelConfig.coldFactor());
         assertEquals(SentinelConfig.DEFAULT_STATISTIC_MAX_RT, SentinelConfig.statisticMaxRt());
+        assertEquals(false, SentinelConfig.shouldSkipRegexIfSimpleRuleMatched());
     }
 
     //    add JVM parameter

sentinel-core/src/test/java/com/alibaba/csp/sentinel/slots/block/RuleManagerTest.java

@@ -51,7 +51,7 @@ public class RuleManagerTest {
         Field regexCacheRules = RuleManager.class.getDeclaredField("regexCacheRules");
         regexCacheRules.setAccessible(true);
         assertEquals(((Map)regexCacheRules.get(ruleManager)).size(), 0);
-        ruleManager.getRules("rule2");
+        ruleManager.getRules("rule");
         assertEquals(((Map)regexCacheRules.get(ruleManager)).size(), 1);
     }