Add DataSource integration for Redis (#102)

- This implementation uses Lettuce as the internal client, and leverages Redis pub-sub feature to implement push mode data source. (by @tigerMoon)

sentinel-extension/pom.xml

@@ -16,6 +16,7 @@
         <module>sentinel-datasource-nacos</module>
         <module>sentinel-datasource-zookeeper</module>
         <module>sentinel-datasource-apollo</module>
+        <module>sentinel-datasource-redis</module>
         <module>sentinel-annotation-aspectj</module>
         <module>sentinel-hot-param-flow-control</module>
     </modules>

sentinel-extension/sentinel-datasource-redis/README.md

@@ -0,0 +1,80 @@
+# Sentinel DataSource Redis
+
+Sentinel DataSource Redis provides integration with Redis. make Redis
+as dynamic rule data source of Sentinel. The data source uses push model (listener) with redis pub/sub feature.
+
+**NOTE**:
+we not support redis cluster as a pub/sub dataSource now.
+
+To use Sentinel DataSource Redis, you should add the following dependency:
+
+```xml
+<dependency>
+    <groupId>com.alibaba.csp</groupId>
+    <artifactId>sentinel-datasource-redis</artifactId>
+    <version>x.y.z</version>
+</dependency>
+
+```
+
+Then you can create an `RedisDataSource` and register to rule managers.
+For instance:
+
+```java
+ReadableDataSource<String, List<FlowRule>> redisDataSource = new RedisDataSource<List<FlowRule>>(redisConnectionConfig, ruleKey, channel, flowConfigParser);
+FlowRuleManager.register2Property(redisDataSource.getProperty());
+```
+
+_**redisConnectionConfig**_ : use `RedisConnectionConfig` class to build your connection config. 
+
+_**ruleKey**_ : when the json rule data publish. it also should save to the key for init read.
+
+_**channel**_ : the channel to listen.  
+
+you can also create multi data source listen for different rule type. 
+
+you can see test cases for usage.
+
+## Before start
+
+RedisDataSource init config by read from redis key `ruleKey`, value store the latest rule config data. 
+so you should first config your redis ruleData in back end. 
+
+since update redis rule data. it should simultaneously send data to `channel`.
+
+you may implement like this (using Redis transaction):
+
+```
+
+MULTI
+PUBLISH channel value
+SET ruleKey value
+EXEC
+
+``` 
+
+
+## How to build RedisConnectionConfig
+
+
+### Build with redis standLone mode
+
+```java
+RedisConnectionConfig config = RedisConnectionConfig.builder()
+                .withHost("localhost")
+                .withPort(6379)
+                .withPassword("pwd")
+                .withDataBase(2)
+                .build();
+
+```
+
+
+### Build with redis sentinel mode
+
+```java
+RedisConnectionConfig config = RedisConnectionConfig.builder()
+                .withRedisSentinel("redisSentinelServer1",5000)
+                .withRedisSentinel("redisSentinelServer2",5001)
+                .withRedisSentinelMasterId("redisSentinelMasterId").build();
+```

sentinel-extension/sentinel-datasource-redis/pom.xml

@@ -0,0 +1,47 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>sentinel-extension</artifactId>
+        <groupId>com.alibaba.csp</groupId>
+        <version>0.2.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>sentinel-datasource-redis</artifactId>
+    <packaging>jar</packaging>
+
+    <properties>
+        <lettuce.version>5.0.1.RELEASE</lettuce.version>
+        <redis.mock.version>0.1.6</redis.mock.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>io.lettuce</groupId>
+            <artifactId>lettuce-core</artifactId>
+            <version>${lettuce.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.alibaba.csp</groupId>
+            <artifactId>sentinel-datasource-extension</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.alibaba</groupId>
+            <artifactId>fastjson</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>ai.grakn</groupId>
+            <artifactId>redis-mock</artifactId>
+            <version>${redis.mock.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+</project>

sentinel-extension/sentinel-datasource-redis/src/main/java/com/alibaba/csp/sentinel/datasource/redis/RedisDataSource.java

@@ -0,0 +1,166 @@
+/*
+ * 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.datasource.redis;
+
+import com.alibaba.csp.sentinel.datasource.AbstractDataSource;
+import com.alibaba.csp.sentinel.datasource.Converter;
+import com.alibaba.csp.sentinel.datasource.redis.config.RedisConnectionConfig;
+import com.alibaba.csp.sentinel.datasource.redis.util.AssertUtil;
+import com.alibaba.csp.sentinel.log.RecordLog;
+import com.alibaba.csp.sentinel.util.StringUtil;
+import io.lettuce.core.RedisClient;
+import io.lettuce.core.RedisURI;
+import io.lettuce.core.api.sync.RedisCommands;
+import io.lettuce.core.pubsub.RedisPubSubAdapter;
+import io.lettuce.core.pubsub.StatefulRedisPubSubConnection;
+import io.lettuce.core.pubsub.api.sync.RedisPubSubCommands;
+
+import java.util.concurrent.TimeUnit;
+
+/**
+ * A read-only {@code DataSource} with Redis backend.
+ * <p>
+ * When data source init,reads form redis with string k-v,value is string format rule config data.
+ * This data source subscribe from specific channel and then data published in redis with this channel,data source
+ * will be notified and then update rule config in time.
+ * </p>
+ *
+ * @author tiger
+ */
+
+public class RedisDataSource<T> extends AbstractDataSource<String, T> {
+
+    private RedisClient redisClient = null;
+
+    private String ruleKey;
+
+    /**
+     * Constructor of {@code RedisDataSource}
+     *
+     * @param connectionConfig redis connection config.
+     * @param ruleKey          data save in redis.
+     * @param channel          subscribe from channel.
+     * @param parser           convert <code>ruleKey<code>`s value to {@literal alibaba/Sentinel} rule type
+     */
+    public RedisDataSource(RedisConnectionConfig connectionConfig, String ruleKey, String channel, Converter<String, T> parser) {
+        super(parser);
+        AssertUtil.notNull(connectionConfig, "redis connection config can not be null");
+        AssertUtil.notEmpty(ruleKey, "redis subscribe ruleKey can not be empty");
+        AssertUtil.notEmpty(channel, "redis subscribe channel can not be empty");
+        this.redisClient = getRedisClient(connectionConfig);
+        this.ruleKey = ruleKey;
+        loadInitialConfig();
+        subscribeFromChannel(channel);
+    }
+
+    /**
+     * build redis client form {@code RedisConnectionConfig} with io.lettuce.
+     *
+     * @return a new {@link RedisClient}
+     */
+    private RedisClient getRedisClient(RedisConnectionConfig connectionConfig) {
+        if (connectionConfig.getRedisSentinels().size() == 0) {
+            RecordLog.info("start standLone mode to connect to redis");
+            return getRedisStandLoneClient(connectionConfig);
+        } else {
+            RecordLog.info("start redis sentinel mode to connect to redis");
+            return getRedisSentinelClient(connectionConfig);
+        }
+    }
+
+    private RedisClient getRedisStandLoneClient(RedisConnectionConfig connectionConfig) {
+        char[] password = connectionConfig.getPassword();
+        String clientName = connectionConfig.getClientName();
+        RedisURI.Builder redisUriBuilder = RedisURI.builder();
+        redisUriBuilder.withHost(connectionConfig.getHost())
+                .withPort(connectionConfig.getPort())
+                .withDatabase(connectionConfig.getDatabase())
+                .withTimeout(connectionConfig.getTimeout(), TimeUnit.MILLISECONDS);
+        if (password != null) {
+            redisUriBuilder.withPassword(connectionConfig.getPassword());
+        }
+        if (StringUtil.isNotEmpty(connectionConfig.getClientName())) {
+            redisUriBuilder.withClientName(clientName);
+        }
+        return RedisClient.create(redisUriBuilder.build());
+    }
+
+    private RedisClient getRedisSentinelClient(RedisConnectionConfig connectionConfig) {
+        char[] password = connectionConfig.getPassword();
+        String clientName = connectionConfig.getClientName();
+        RedisURI.Builder sentinelRedisUriBuilder = RedisURI.builder();
+        for (RedisConnectionConfig config : connectionConfig.getRedisSentinels()) {
+            sentinelRedisUriBuilder.withSentinel(config.getHost(), config.getPort());
+        }
+        if (password != null) {
+            sentinelRedisUriBuilder.withPassword(connectionConfig.getPassword());
+        }
+        if (StringUtil.isNotEmpty(connectionConfig.getClientName())) {
+            sentinelRedisUriBuilder.withClientName(clientName);
+        }
+        sentinelRedisUriBuilder.withSentinelMasterId(connectionConfig.getRedisSentinelMasterId())
+                .withTimeout(connectionConfig.getTimeout(), TimeUnit.MILLISECONDS);
+        return RedisClient.create(sentinelRedisUriBuilder.build());
+    }
+
+    private void subscribeFromChannel(String channel) {
+        StatefulRedisPubSubConnection<String, String> pubSubConnection = redisClient.connectPubSub();
+        RedisPubSubAdapter<String, String> adapterListener = new DelegatingRedisPubSubListener();
+        pubSubConnection.addListener(adapterListener);
+        RedisPubSubCommands<String, String> sync = pubSubConnection.sync();
+        sync.subscribe(channel);
+    }
+
+    private void loadInitialConfig() {
+        try {
+            T newValue = loadConfig();
+            if (newValue == null) {
+                RecordLog.warn("[RedisDataSource] WARN: initial config is null, you may have to check your data source");
+            }
+            getProperty().updateValue(newValue);
+        } catch (Exception ex) {
+            RecordLog.warn("[RedisDataSource] Error when loading initial config", ex);
+        }
+    }
+
+    @Override
+    public String readSource() throws Exception {
+        if (this.redisClient == null) {
+            throw new IllegalStateException("redis client has not been initialized or error occurred");
+        }
+        RedisCommands<String, String> stringRedisCommands = redisClient.connect().sync();
+        return stringRedisCommands.get(ruleKey);
+    }
+
+    @Override
+    public void close() throws Exception {
+        redisClient.shutdown();
+    }
+
+    private class DelegatingRedisPubSubListener extends RedisPubSubAdapter<String, String> {
+
+        DelegatingRedisPubSubListener() {
+        }
+
+        @Override
+        public void message(String channel, String message) {
+            RecordLog.info(String.format("[RedisDataSource] New property value received for channel %s: %s",  channel, message));
+            getProperty().updateValue(parser.convert(message));
+        }
+    }
+
+}