Update cluster related logic in core

- Remove "borrow-from-ref" mode
- Improve flow checker to support both embedded server mode and client mode

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

sentinel-core/src/main/java/com/alibaba/csp/sentinel/cluster/log/ClusterStatLogUtil.java → sentinel-core/src/main/java/com/alibaba/csp/sentinel/cluster/log/ClusterClientStatLogUtil.java

@@ -15,8 +15,6 @@
  */
 package com.alibaba.csp.sentinel.cluster.log;
 
-import java.io.File;
-
 import com.alibaba.csp.sentinel.eagleeye.EagleEye;
 import com.alibaba.csp.sentinel.eagleeye.StatLogger;
 import com.alibaba.csp.sentinel.log.LogBase;
@@ -26,16 +24,16 @@ import com.alibaba.csp.sentinel.log.LogBase;
  * @author Eric Zhao
  * @since 1.4.0
  */
-public final class ClusterStatLogUtil {
+public final class ClusterClientStatLogUtil {
 
-    private static final String FILE_NAME = "sentinel-cluster.log";
+    private static final String FILE_NAME = "sentinel-cluster-client.log";
 
     private static StatLogger statLogger;
 
     static {
         String path = LogBase.getLogBaseDir() + FILE_NAME;
 
-        statLogger = EagleEye.statLoggerBuilder("sentinel-cluster-record")
+        statLogger = EagleEye.statLoggerBuilder("sentinel-cluster-client-record")
             .intervalSeconds(1)
             .entryDelimiter('|')
             .keyDelimiter(',')
@@ -55,5 +53,5 @@ public final class ClusterStatLogUtil {
         statLogger.stat(msg).count(count);
     }
 
-    private ClusterStatLogUtil() {}
+    private ClusterClientStatLogUtil() {}
 }

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

@@ -22,7 +22,7 @@ package com.alibaba.csp.sentinel.slots.block;
 public final class ClusterRuleConstant {
 
     public static final int FLOW_CLUSTER_STRATEGY_NORMAL = 0;
-    public static final int FLOW_CLUSTER_STRATEGY_REF = 1;
+    public static final int FLOW_CLUSTER_STRATEGY_BORROW_REF = 1;
 
     public static final int FLOW_THRESHOLD_AVG_LOCAL = 0;
     public static final int FLOW_THRESHOLD_GLOBAL = 1;

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

@@ -34,17 +34,13 @@ public class ClusterFlowConfig {
      * Threshold type (average by local value or global value).
      */
     private int thresholdType = ClusterRuleConstant.FLOW_THRESHOLD_AVG_LOCAL;
-    private boolean fallbackToLocalWhenFail;
+    private boolean fallbackToLocalWhenFail = true;
 
     /**
-     * 0: normal; 1: using reference (borrow from reference).
+     * 0: normal.
      */
     private int strategy = ClusterRuleConstant.FLOW_CLUSTER_STRATEGY_NORMAL;
 
-    private Long refFlowId;
-    private int refSampleCount = 10;
-    private double refRatio = 1d;
-
     public Long getFlowId() {
         return flowId;
     }
@@ -72,33 +68,6 @@ public class ClusterFlowConfig {
         return this;
     }
 
-    public Long getRefFlowId() {
-        return refFlowId;
-    }
-
-    public ClusterFlowConfig setRefFlowId(Long refFlowId) {
-        this.refFlowId = refFlowId;
-        return this;
-    }
-
-    public int getRefSampleCount() {
-        return refSampleCount;
-    }
-
-    public ClusterFlowConfig setRefSampleCount(int refSampleCount) {
-        this.refSampleCount = refSampleCount;
-        return this;
-    }
-
-    public double getRefRatio() {
-        return refRatio;
-    }
-
-    public ClusterFlowConfig setRefRatio(double refRatio) {
-        this.refRatio = refRatio;
-        return this;
-    }
-
     public boolean isFallbackToLocalWhenFail() {
         return fallbackToLocalWhenFail;
     }
@@ -118,24 +87,15 @@ public class ClusterFlowConfig {
         if (thresholdType != that.thresholdType) { return false; }
         if (fallbackToLocalWhenFail != that.fallbackToLocalWhenFail) { return false; }
         if (strategy != that.strategy) { return false; }
-        if (refSampleCount != that.refSampleCount) { return false; }
-        if (Double.compare(that.refRatio, refRatio) != 0) { return false; }
-        if (flowId != null ? !flowId.equals(that.flowId) : that.flowId != null) { return false; }
-        return refFlowId != null ? refFlowId.equals(that.refFlowId) : that.refFlowId == null;
+        return flowId != null ? flowId.equals(that.flowId) : that.flowId == null;
     }
 
     @Override
     public int hashCode() {
-        int result;
-        long temp;
-        result = flowId != null ? flowId.hashCode() : 0;
+        int result = flowId != null ? flowId.hashCode() : 0;
         result = 31 * result + thresholdType;
         result = 31 * result + (fallbackToLocalWhenFail ? 1 : 0);
         result = 31 * result + strategy;
-        result = 31 * result + (refFlowId != null ? refFlowId.hashCode() : 0);
-        result = 31 * result + refSampleCount;
-        temp = Double.doubleToLongBits(refRatio);
-        result = 31 * result + (int)(temp ^ (temp >>> 32));
         return result;
     }
 
@@ -146,9 +106,6 @@ public class ClusterFlowConfig {
             ", thresholdType=" + thresholdType +
             ", fallbackToLocalWhenFail=" + fallbackToLocalWhenFail +
             ", strategy=" + strategy +
-            ", refFlowId=" + refFlowId +
-            ", refSampleCount=" + refSampleCount +
-            ", refRatio=" + refRatio +
             '}';
     }
 }

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

@@ -15,10 +15,12 @@
  */
 package com.alibaba.csp.sentinel.slots.block.flow;
 
-import com.alibaba.csp.sentinel.cluster.ClusterTokenClient;
-import com.alibaba.csp.sentinel.cluster.TokenClientProvider;
+import com.alibaba.csp.sentinel.cluster.ClusterStateManager;
+import com.alibaba.csp.sentinel.cluster.server.EmbeddedClusterTokenServerProvider;
+import com.alibaba.csp.sentinel.cluster.client.TokenClientProvider;
 import com.alibaba.csp.sentinel.cluster.TokenResultStatus;
 import com.alibaba.csp.sentinel.cluster.TokenResult;
+import com.alibaba.csp.sentinel.cluster.TokenService;
 import com.alibaba.csp.sentinel.context.Context;
 import com.alibaba.csp.sentinel.log.RecordLog;
 import com.alibaba.csp.sentinel.node.DefaultNode;
@@ -62,38 +64,6 @@ final class FlowRuleChecker {
         return rule.getRater().canPass(selectedNode, acquireCount);
     }
 
-    static boolean passClusterCheck(FlowRule rule, Context context, DefaultNode node, int acquireCount,
-                                    boolean prioritized) {
-        try {
-            ClusterTokenClient client = TokenClientProvider.getClient();
-            if (client != null) {
-                TokenResult result = client.requestToken(rule.getClusterConfig().getFlowId(), acquireCount,
-                    prioritized);
-                switch (result.getStatus()) {
-                    case TokenResultStatus.OK:
-                        return true;
-                    case TokenResultStatus.SHOULD_WAIT:
-                        // Wait for next tick.
-                        Thread.sleep(result.getWaitInMs());
-                        return true;
-                    case TokenResultStatus.NO_RULE_EXISTS:
-                    case TokenResultStatus.BAD_REQUEST:
-                    case TokenResultStatus.FAIL:
-                        return passLocalCheck(rule, context, node, acquireCount, prioritized);
-                    case TokenResultStatus.BLOCKED:
-                    default:
-                        return false;
-                }
-            }
-            // If client is absent, then fallback to local mode.
-        } catch (Throwable ex) {
-            RecordLog.warn("[FlowRuleChecker] Request cluster token unexpected failed", ex);
-        }
-        // TODO: choose whether fallback to local or inactivate the rule.
-        // Downgrade to local flow control when token client or server for this rule is not available.
-        return passLocalCheck(rule, context, node, acquireCount, prioritized);
-    }
-
     static Node selectReferenceNode(FlowRule rule, Context context, DefaultNode node) {
         String refResource = rule.getRefResource();
         int strategy = rule.getStrategy();
@@ -153,5 +123,67 @@ final class FlowRuleChecker {
         return null;
     }
 
+    private static boolean passClusterCheck(FlowRule rule, Context context, DefaultNode node, int acquireCount,
+                                            boolean prioritized) {
+        try {
+            TokenService clusterService = pickClusterService();
+            if (clusterService == null) {
+                return fallbackToLocalOrPass(rule, context, node, acquireCount, prioritized);
+            }
+            long flowId = rule.getClusterConfig().getFlowId();
+            TokenResult result = clusterService.requestToken(flowId, acquireCount, prioritized);
+            return applyTokenResult(result, rule, context, node, acquireCount, prioritized);
+            // If client is absent, then fallback to local mode.
+        } catch (Throwable ex) {
+            RecordLog.warn("[FlowRuleChecker] Request cluster token unexpected failed", ex);
+        }
+        // Fallback to local flow control when token client or server for this rule is not available.
+        // If fallback is not enabled, then directly pass.
+        return fallbackToLocalOrPass(rule, context, node, acquireCount, prioritized);
+    }
+
+    private static boolean fallbackToLocalOrPass(FlowRule rule, Context context, DefaultNode node, int acquireCount,
+                                                 boolean prioritized) {
+        if (rule.getClusterConfig().isFallbackToLocalWhenFail()) {
+            return passLocalCheck(rule, context, node, acquireCount, prioritized);
+        } else {
+            // The rule won't be activated, just pass.
+            return true;
+        }
+    }
+
+    private static TokenService pickClusterService() {
+        if (ClusterStateManager.isClient()) {
+            return TokenClientProvider.getClient();
+        }
+        if (ClusterStateManager.isServer()) {
+            return EmbeddedClusterTokenServerProvider.getServer();
+        }
+        return null;
+    }
+
+    private static boolean applyTokenResult(/*@NonNull*/ TokenResult result, FlowRule rule, Context context, DefaultNode node,
+                                                 int acquireCount, boolean prioritized) {
+        switch (result.getStatus()) {
+            case TokenResultStatus.OK:
+                return true;
+            case TokenResultStatus.SHOULD_WAIT:
+                // Wait for next tick.
+                try {
+                    Thread.sleep(result.getWaitInMs());
+                } catch (InterruptedException e) {
+                    e.printStackTrace();
+                }
+                return true;
+            case TokenResultStatus.NO_RULE_EXISTS:
+            case TokenResultStatus.BAD_REQUEST:
+            case TokenResultStatus.FAIL:
+                return fallbackToLocalOrPass(rule, context, node, acquireCount, prioritized);
+            case TokenResultStatus.BLOCKED:
+            default:
+                return false;
+        }
+    }
+
     private FlowRuleChecker() {}
 }

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

@@ -189,10 +189,8 @@ public final class FlowRuleUtil {
         switch (rule.getStrategy()) {
             case ClusterRuleConstant.FLOW_CLUSTER_STRATEGY_NORMAL:
                 return true;
-            case ClusterRuleConstant.FLOW_CLUSTER_STRATEGY_REF:
-                return validClusterRuleId(clusterConfig.getRefFlowId());
             default:
-                return true;
+                return false;
         }
     }
 

sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/base/LeapArray.java

@@ -211,16 +211,16 @@ public abstract class LeapArray<T> {
         if (timeMillis < 0) {
             return null;
         }
-        int idx = calculateTimeIdx(timeMillis);
-
-        long previousTime = timeMillis - windowLengthInMs;
+        long timeId = (timeMillis - windowLengthInMs) / windowLengthInMs;
+        int idx = (int)(timeId % array.length());
+        timeMillis = timeMillis - windowLengthInMs;
         WindowWrap<T> wrap = array.get(idx);
 
         if (wrap == null || isWindowDeprecated(wrap)) {
             return null;
         }
 
-        if (wrap.windowStart() + windowLengthInMs < previousTime) {
+        if (wrap.windowStart() + windowLengthInMs < (timeMillis)) {
             return null;
         }
 

sentinel-core/src/main/java/com/alibaba/csp/sentinel/util/function/Supplier.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright 1999-2018 Alibaba Group Holding Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.alibaba.csp.sentinel.util.function;
+
+/**
+ * Supplier functional interface from JDK 8.
+ */
+public interface Supplier<T> {
+
+    /**
+     * Gets a result.
+     *
+     * @return a result
+     */
+    T get();
+}