From a9918f2332277bd211bf959a55e1b6c4c1357fea Mon Sep 17 00:00:00 2001
From: chuntaojun <liaochuntao@live.com>
Date: Sun, 19 Apr 2020 09:25:28 +0800
Subject: [PATCH] refactor: request forwarding logic adjustment

---
 .../server/filter/TransferToLeaderFilter.java |  4 +-
 .../consistency/ConsistencyProtocol.java      |  2 +-
 .../nacos/consistency/ProtocolMetaData.java   |  9 --
 .../src/main/resources/application.properties | 30 +++----
 .../lookup/AddressServerMemberLookup.java     |  4 +-
 .../cluster/lookup/DiscoveryMemberLookup.java |  2 +-
 .../id/SnakeFlowerIdGenerator.java            | 86 +++++++++++--------
 .../core/distributed/raft/JRaftServer.java    |  2 +
 8 files changed, 72 insertions(+), 67 deletions(-)

diff --git a/config/src/main/java/com/alibaba/nacos/config/server/filter/TransferToLeaderFilter.java b/config/src/main/java/com/alibaba/nacos/config/server/filter/TransferToLeaderFilter.java
index ce944634d..98d34704b 100644
--- a/config/src/main/java/com/alibaba/nacos/config/server/filter/TransferToLeaderFilter.java
+++ b/config/src/main/java/com/alibaba/nacos/config/server/filter/TransferToLeaderFilter.java
@@ -135,7 +135,9 @@ public class TransferToLeaderFilter implements Filter {
 
 				String val = req.getHeader(Constants.FORWARD_LEADER);
 				final int transferCnt = Integer.parseInt(StringUtils.isEmpty(val) ? "0" : val) + 1;
-				if (transferCnt > MAX_TRANSFER_CNT) {
+
+				// Requests can only be forwarded once if a downgrade is not triggered
+				if (transferCnt > MAX_TRANSFER_CNT && !downgrading) {
 					resp.sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE,
 							"Exceeded forwarding times:" + req.getMethod() + ":" + req.getRequestURI());
 					return;
diff --git a/consistency/src/main/java/com/alibaba/nacos/consistency/ConsistencyProtocol.java b/consistency/src/main/java/com/alibaba/nacos/consistency/ConsistencyProtocol.java
index e18bdf697..a199c9637 100644
--- a/consistency/src/main/java/com/alibaba/nacos/consistency/ConsistencyProtocol.java
+++ b/consistency/src/main/java/com/alibaba/nacos/consistency/ConsistencyProtocol.java
@@ -26,7 +26,7 @@ import java.util.concurrent.CompletableFuture;
 
 /**
  * Has nothing to do with the specific implementation of the consistency protocol
- * Initialization sequence： init(Config) => loadLogProcessor(List)
+ * Initialization sequence： init(Config)
  *
  * <ul>
  *     <li>{@link Config} : Relevant configuration information required by the consistency protocol,
diff --git a/consistency/src/main/java/com/alibaba/nacos/consistency/ProtocolMetaData.java b/consistency/src/main/java/com/alibaba/nacos/consistency/ProtocolMetaData.java
index 918c332da..3c75cd0ee 100644
--- a/consistency/src/main/java/com/alibaba/nacos/consistency/ProtocolMetaData.java
+++ b/consistency/src/main/java/com/alibaba/nacos/consistency/ProtocolMetaData.java
@@ -34,15 +34,6 @@ import java.util.concurrent.locks.ReentrantReadWriteLock;
  * Consistent protocol metadata information, <Key, <Key, Value >> structure
  * Listeners that can register to listen to changes in value
  *
- * <ul>
- *     <li>
- *         <global, <cluster, List <String >> metadata information that exists by default, that is, all node information of the entire cluster
- *     </li>
- *     <li>
- *         <global, <self, String> The metadata information existing by default, that is, the IP: PORT information of the current node
- *     </li>
- * </ul>
- *
  * @author <a href="mailto:liaochuntao@live.com">liaochuntao</a>
  */
 @SuppressWarnings("PMD.Rule:CollectionInitShouldAssignCapacityRule")
diff --git a/console/src/main/resources/application.properties b/console/src/main/resources/application.properties
index 31162a72d..be768c886 100644
--- a/console/src/main/resources/application.properties
+++ b/console/src/main/resources/application.properties
@@ -13,18 +13,16 @@ server.port=8848
 
 
 #*************** Core Related Configurations ***************#
-
-### Which nacos embedded distributed ID is turned on,
-### If an external implementation is provided, the external implementation is automatically selected
-nacos.core.id-generator.type=default
-### The step size for each fetch of the embedded distributed ID
-nacos.core.id-generator.default.acquire.step=100
-
-### If nacos.core.idGenerator.type=snakeflower, You need to set the dataCenterID manually
+### set the dataCenterID manually
 # nacos.core.snowflake.data-center=
-### If nacos.core.idGenerator.type=snakeflower, You need to set the WorkerID manually
+### set the WorkerID manually
 # nacos.core.snowflake.worker-id=
 
+### MemberLookup
+# for AddressServerMemberLookup
+# Maximum number of retries to query the address server upon initialization
+# nacos.core.address-server.retry=5
+
 #*************** Config Module Related Configurations ***************#
 ### If user MySQL as datasource:
 # spring.datasource.platform=mysql
@@ -33,9 +31,10 @@ nacos.core.id-generator.default.acquire.step=100
 # db.num=1
 
 ### Connect URL of DB:
-# db.url.0=jdbc:mysql://1.1.1.1:3306/nacos?characterEncoding=utf8&connectTimeout=1000&socketTimeout=3000&autoReconnect=true
-# db.user=user
-# db.password=password
+#db.num=1
+#db.url.0=jdbc:mysql://127.0.0.1:3306/nacos?characterEncoding=utf8&connectTimeout=1000&socketTimeout=3000&autoReconnect=true&useUnicode=true&useSSL=false&serverTimezone=UTC
+#db.user=root
+#db.password=1017
 
 
 #*************** Naming Module Related Configurations ***************#
@@ -191,10 +190,3 @@ nacos.core.protocol.distro.data.sync_retry_delay_ms=5000
 nacos.core.protocol.distro.data.distro_enabled=true
 ### Data synchronization retry strategy
 nacos.core.protocol.distro.data.retry_policy=simple
-
-# DB Configuration
-#spring.datasource.platform=mysql
-#db.num=1
-#db.url.0=jdbc:mysql://127.0.0.1:3306/nacos?characterEncoding=utf8&connectTimeout=1000&socketTimeout=3000&autoReconnect=true&useUnicode=true&useSSL=false&serverTimezone=UTC
-#db.user=root
-#db.password=1017
\ No newline at end of file
diff --git a/core/src/main/java/com/alibaba/nacos/core/cluster/lookup/AddressServerMemberLookup.java b/core/src/main/java/com/alibaba/nacos/core/cluster/lookup/AddressServerMemberLookup.java
index 41bcfc766..9e5eea3b9 100644
--- a/core/src/main/java/com/alibaba/nacos/core/cluster/lookup/AddressServerMemberLookup.java
+++ b/core/src/main/java/com/alibaba/nacos/core/cluster/lookup/AddressServerMemberLookup.java
@@ -57,7 +57,6 @@ public class AddressServerMemberLookup extends AbstractMemberLookup {
 	private NSyncHttpClient syncHttpClient = HttpClientManager
 			.newSyncHttpClient(AddressServerMemberLookup.class.getCanonicalName());
 	private AddressServerSyncTask task;
-	private int maxRetry = Integer.getInteger("nacos.address-server.retry", 5);
 	private volatile boolean shutdown = false;
 
 	@Override
@@ -97,6 +96,7 @@ public class AddressServerMemberLookup extends AbstractMemberLookup {
 		// Repeat three times, successfully jump out
 		boolean success = false;
 		Throwable ex = null;
+		int maxRetry = ApplicationUtils.getProperty("nacos.core.address-server.retry", Integer.class, 5);
 		for (int i = 0; i < maxRetry; i ++) {
 			try {
 				syncFromAddressUrl();
@@ -108,7 +108,7 @@ public class AddressServerMemberLookup extends AbstractMemberLookup {
 			}
 		}
 		if (!success) {
-			throw new RuntimeException(ex);
+			throw new NacosException(NacosException.SERVER_ERROR, ex);
 		}
 
 		task = new AddressServerSyncTask();
diff --git a/core/src/main/java/com/alibaba/nacos/core/cluster/lookup/DiscoveryMemberLookup.java b/core/src/main/java/com/alibaba/nacos/core/cluster/lookup/DiscoveryMemberLookup.java
index 4a938cc98..cc5657408 100644
--- a/core/src/main/java/com/alibaba/nacos/core/cluster/lookup/DiscoveryMemberLookup.java
+++ b/core/src/main/java/com/alibaba/nacos/core/cluster/lookup/DiscoveryMemberLookup.java
@@ -56,7 +56,7 @@ import java.util.Set;
  *     │                                            │        Member A         │  │
  *     │                                            │   [ip1.port,ip2.port]   │  │
  *     │       ┌───────────────────────┐            │                         │  │
- *     │       │  GossipMemberLookup   │            └─────────────────────────┘  │
+ *     │       │ DiscoveryMemberLookup │            └─────────────────────────┘  │
  *     │       └───────────────────────┘                                         │
  *     │                   │                                                     │
  *     │                   │                                     ┌───────────────┼────────────────[ip1:port,ip2:port,ip3:port]───────────────────────┐
diff --git a/core/src/main/java/com/alibaba/nacos/core/distributed/id/SnakeFlowerIdGenerator.java b/core/src/main/java/com/alibaba/nacos/core/distributed/id/SnakeFlowerIdGenerator.java
index 271d6be77..4c2f18146 100644
--- a/core/src/main/java/com/alibaba/nacos/core/distributed/id/SnakeFlowerIdGenerator.java
+++ b/core/src/main/java/com/alibaba/nacos/core/distributed/id/SnakeFlowerIdGenerator.java
@@ -17,6 +17,7 @@ package com.alibaba.nacos.core.distributed.id;
 
 import com.alibaba.nacos.consistency.IdGenerator;
 import com.alibaba.nacos.core.exception.SnakflowerException;
+import com.alibaba.nacos.core.utils.ApplicationUtils;
 
 import java.net.InetAddress;
 import java.net.UnknownHostException;
@@ -30,7 +31,7 @@ import java.util.Map;
  * on the Raft Term and the maximum DataCenterId information
  *
  * <strong>WorkerId</strong> generation policy: Calculate the InetAddress hashcode
- *
+ * <p>
  * The repeat rate of the dataCenterId, the value of the maximum dataCenterId times the
  * time of each Raft election. The time for raft to select the master is generally measured
  * in seconds. If the interval of an election is 5 seconds, it will take 150 seconds for
@@ -48,7 +49,7 @@ public class SnakeFlowerIdGenerator implements IdGenerator {
 	private static final long WORKER_ID_BITS = 5L;
 	private static final long DATA_CENTER_ID_BITS = 5L;
 	public static final long MAX_WORKER_ID = ~(-1L << WORKER_ID_BITS);
-    public static final long MAX_DATA_CENTER_ID = ~(-1L << DATA_CENTER_ID_BITS);
+	public static final long MAX_DATA_CENTER_ID = ~(-1L << DATA_CENTER_ID_BITS);
 
 	private static final long SEQUENCE_BITS = 12L;
 	private static final long SEQUENCE_BITS1 = SEQUENCE_BITS;
@@ -56,47 +57,62 @@ public class SnakeFlowerIdGenerator implements IdGenerator {
 	private static final long TIMESTAMP_LEFT_SHIFT =
 			SEQUENCE_BITS + WORKER_ID_BITS + DATA_CENTER_ID_BITS;
 	private static final long SEQUENCE_MASK = ~(-1L << SEQUENCE_BITS);
+	private static final long MAX_OFFSET = 5L;
 
-    private static long workerId;
-    private static volatile long dataCenterId = 1L;
+	private static long workerId = -1L;
+	private static volatile long dataCenterId = -1L;
 
 	private volatile long currentId;
 	private long sequence = 0L;
 	private long lastTimestamp = -1L;
 
-	private final long MAX_OFFSET = 5L;
 
-    public static void setDataCenterId(long dataCenterId) {
-        SnakeFlowerIdGenerator.dataCenterId = dataCenterId;
-    }
+	public static void setDataCenterId(long dataCenterId) {
+		SnakeFlowerIdGenerator.dataCenterId = dataCenterId;
+	}
 
-    static {
-        InetAddress address;
-        try {
-            address = InetAddress.getLocalHost();
-        }
-        catch (final UnknownHostException e) {
-            throw new IllegalStateException(
-                    "Cannot get LocalHost InetAddress, please check your network!");
-        }
-        byte[] ipAddressByteArray = address.getAddress();
-        workerId = (
-                ((ipAddressByteArray[ipAddressByteArray.length - 2] & 0B11) << Byte.SIZE)
-                        + (ipAddressByteArray[ipAddressByteArray.length - 1] & 0xFF));
-    }
+	{
+		long dataCenterId = ApplicationUtils
+				.getProperty("nacos.core.snowflake.data-center", Integer.class, -1);
+		long workerId = ApplicationUtils
+				.getProperty("nacos.core.snowflake.worker-id", Integer.class, -1);
+
+		if (dataCenterId != -1) {
+			SnakeFlowerIdGenerator.dataCenterId = dataCenterId;
+		} else {
+			SnakeFlowerIdGenerator.dataCenterId = 1L;
+		}
+		if (workerId != -1) {
+			SnakeFlowerIdGenerator.workerId = workerId;
+		}
+		else {
+			InetAddress address;
+			try {
+				address = InetAddress.getLocalHost();
+			}
+			catch (final UnknownHostException e) {
+				throw new IllegalStateException(
+						"Cannot get LocalHost InetAddress, please check your network!");
+			}
+			byte[] ipAddressByteArray = address.getAddress();
+			SnakeFlowerIdGenerator.workerId = (((ipAddressByteArray[ipAddressByteArray.length - 2] & 0B11)
+					<< Byte.SIZE) + (ipAddressByteArray[ipAddressByteArray.length - 1]
+					& 0xFF));
+		}
+	}
 
 	@Override
-    public void init() {
-        initialize(workerId, dataCenterId);
-    }
+	public void init() {
+		initialize(workerId, dataCenterId);
+	}
 
 	@Override
-    public long currentId() {
+	public long currentId() {
 		return currentId;
 	}
 
 	@Override
-    public synchronized long nextId() {
+	public synchronized long nextId() {
 		long timestamp = timeGen();
 
 		if (timestamp < lastTimestamp) {
@@ -109,14 +125,16 @@ public class SnakeFlowerIdGenerator implements IdGenerator {
 			if (offset <= MAX_OFFSET) {
 				try {
 					wait(offset << 1);
-				} catch (InterruptedException ignore) {
+				}
+				catch (InterruptedException ignore) {
 					Thread.interrupted();
 				}
 				timestamp = timeGen();
 				if (timestamp < lastTimestamp) {
 					throw exception;
 				}
-			} else {
+			}
+			else {
 				throw exception;
 			}
 		}
@@ -138,7 +156,7 @@ public class SnakeFlowerIdGenerator implements IdGenerator {
 	}
 
 	@Override
-    public Map<Object, Object> info() {
+	public Map<Object, Object> info() {
 		Map<Object, Object> info = new HashMap<>(4);
 		info.put("currentId", currentId);
 		info.put("dataCenterId", dataCenterId);
@@ -158,15 +176,15 @@ public class SnakeFlowerIdGenerator implements IdGenerator {
 		if (workerId > MAX_WORKER_ID || workerId < 0) {
 			throw new IllegalArgumentException(
 					String.format("worker Id can't be greater than %d or less than 0",
-                            MAX_WORKER_ID));
+							MAX_WORKER_ID));
 		}
 		if (dataCenterId > MAX_DATA_CENTER_ID || dataCenterId < 0) {
 			throw new IllegalArgumentException(
 					String.format("dataCenter Id can't be greater than %d or less than 0",
-                            MAX_DATA_CENTER_ID));
+							MAX_DATA_CENTER_ID));
 		}
-        SnakeFlowerIdGenerator.workerId = workerId;
-        SnakeFlowerIdGenerator.dataCenterId = dataCenterId;
+		SnakeFlowerIdGenerator.workerId = workerId;
+		SnakeFlowerIdGenerator.dataCenterId = dataCenterId;
 	}
 
 	/**
diff --git a/core/src/main/java/com/alibaba/nacos/core/distributed/raft/JRaftServer.java b/core/src/main/java/com/alibaba/nacos/core/distributed/raft/JRaftServer.java
index 7ec9656cf..efa690839 100644
--- a/core/src/main/java/com/alibaba/nacos/core/distributed/raft/JRaftServer.java
+++ b/core/src/main/java/com/alibaba/nacos/core/distributed/raft/JRaftServer.java
@@ -255,6 +255,8 @@ public class JRaftServer {
 			// Ensure that each Raft Group has its own configuration and NodeOptions
 			Configuration configuration = conf.copy();
 			NodeOptions copy = nodeOptions.copy();
+			// Here, the LogProcessor is passed into StateMachine, and when the StateMachine
+			// triggers onApply, the onApply of the LogProcessor is actually called
 			NacosStateMachine machine = new NacosStateMachine(this, processor);
 
 			copy.setLogUri(logUri);