Add cluster embedded mode handling logic for parameter flow checker

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

sentinel-extension/sentinel-parameter-flow-control/src/main/java/com/alibaba/csp/sentinel/slots/block/flow/param/ParamFlowChecker.java

@@ -22,10 +22,12 @@ import java.util.Collections;
 import java.util.List;
 import java.util.Set;
 
-import com.alibaba.csp.sentinel.cluster.client.ClusterTokenClient;
+import com.alibaba.csp.sentinel.cluster.ClusterStateManager;
+import com.alibaba.csp.sentinel.cluster.TokenService;
 import com.alibaba.csp.sentinel.cluster.client.TokenClientProvider;
 import com.alibaba.csp.sentinel.cluster.TokenResult;
 import com.alibaba.csp.sentinel.cluster.TokenResultStatus;
+import com.alibaba.csp.sentinel.cluster.server.EmbeddedClusterTokenServerProvider;
 import com.alibaba.csp.sentinel.log.RecordLog;
 import com.alibaba.csp.sentinel.slotchain.ResourceWrapper;
 import com.alibaba.csp.sentinel.slots.block.RuleConstant;
@@ -134,13 +136,15 @@ final class ParamFlowChecker {
     private static boolean passClusterCheck(ResourceWrapper resourceWrapper, ParamFlowRule rule, int count,
                                             Object value) {
         try {
-            ClusterTokenClient client = TokenClientProvider.getClient();
-            if (client == null) {
-                return true;
-            }
             Collection<Object> params = toCollection(value);
 
-            TokenResult result = client.requestParamToken(rule.getClusterConfig().getFlowId(), count, params);
+            TokenService clusterService = pickClusterService();
+            if (clusterService == null) {
+                // No available cluster client or server, fallback to local or pass in need.
+                return fallbackToLocalOrPass(resourceWrapper, rule, count, params);
+            }
+
+            TokenResult result = clusterService.requestParamToken(rule.getClusterConfig().getFlowId(), count, params);
             switch (result.getStatus()) {
                 case TokenResultStatus.OK:
                     return true;
@@ -165,5 +169,15 @@ final class ParamFlowChecker {
         }
     }
 
+    private static TokenService pickClusterService() {
+        if (ClusterStateManager.isClient()) {
+            return TokenClientProvider.getClient();
+        }
+        if (ClusterStateManager.isServer()) {
+            return EmbeddedClusterTokenServerProvider.getServer();
+        }
+        return null;
+    }
+
     private ParamFlowChecker() {}
 }