Improve cluster embedded demo

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

sentinel-demo/sentinel-demo-cluster/sentinel-demo-cluster-embedded/src/main/java/com/alibaba/csp/sentinel/demo/cluster/init/DemoClusterInitFunc.java

@@ -58,14 +58,19 @@ public class DemoClusterInitFunc implements InitFunc {
 
     @Override
     public void init() throws Exception {
-        // Init token client related data source.
+        // Register client dynamic rule data source.
         initDynamicRuleProperty();
 
+        // Register token client related data source.
+        // Token client common config:
         initClientConfigProperty();
+        // Token client assign config (e.g. target token server) retrieved from assign map:
         initClientServerAssignProperty();
 
-        // Init token server related data source.
+        // Register token server related data source.
+        // Register dynamic rule data source supplier for token server:
         registerClusterRuleSupplier();
+        // Token server transport config extracted from assign map:
         initServerTransportConfigProperty();
 
         // Init cluster state property for extracting mode from cluster map data source.
@@ -101,15 +106,16 @@ public class DemoClusterInitFunc implements InitFunc {
 
     private void registerClusterRuleSupplier() {
         // Register cluster flow rule property supplier which creates data source by namespace.
+        // Flow rule dataId format: ${namespace}-flow-rules
         ClusterFlowRuleManager.setPropertySupplier(namespace -> {
             ReadableDataSource<String, List<FlowRule>> ds = new NacosDataSource<>(remoteAddress, groupId,
-                flowDataId, source -> JSON.parseObject(source, new TypeReference<List<FlowRule>>() {}));
+                namespace + DemoConstants.FLOW_POSTFIX, source -> JSON.parseObject(source, new TypeReference<List<FlowRule>>() {}));
             return ds.getProperty();
         });
         // Register cluster parameter flow rule property supplier which creates data source by namespace.
         ClusterParamFlowRuleManager.setPropertySupplier(namespace -> {
             ReadableDataSource<String, List<ParamFlowRule>> ds = new NacosDataSource<>(remoteAddress, groupId,
-                paramDataId, source -> JSON.parseObject(source, new TypeReference<List<ParamFlowRule>>() {}));
+                namespace + DemoConstants.PARAM_FLOW_POSTFIX, source -> JSON.parseObject(source, new TypeReference<List<ParamFlowRule>>() {}));
             return ds.getProperty();
         });
     }
@@ -147,6 +153,8 @@ public class DemoClusterInitFunc implements InitFunc {
         if (groupList.stream().anyMatch(this::machineEqual)) {
             return ClusterStateManager.CLUSTER_SERVER;
         }
+        // If current machine belongs to any of the token server group, then it's token client.
+        // Otherwise it's unassigned, should be set to NOT_STARTED.
         boolean canBeClient = groupList.stream()
             .flatMap(e -> e.getClientSet().stream())
             .anyMatch(e -> e.equals(getCurrentMachineId()));
@@ -180,8 +188,9 @@ public class DemoClusterInitFunc implements InitFunc {
     }
 
     private String getCurrentMachineId() {
+        // Note: this may not work well for container-based env.
         return HostNameUtil.getIp() + SEPARATOR + TransportConfig.getRuntimePort();
     }
 
     private static final String SEPARATOR = "@";
-}
+}