Refactor Sentinel data source hierarchy

- Spilt DataSource into two types: ReadableDataSource and WritableDataSource
- The AbstractDataSource now is read-only
- Refactor the file data source for writable implementation
- Rename: ConfigParser -> Converter (represents both encoder `T -> S` and decoder `S -> T`)
- Some other refinement

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

sentinel-extension/sentinel-datasource-apollo/src/main/java/com/alibaba/csp/sentinel/datasource/apollo/ApolloDataSource.java

@@ -1,9 +1,9 @@
 package com.alibaba.csp.sentinel.datasource.apollo;
 
 import com.alibaba.csp.sentinel.datasource.AbstractDataSource;
-import com.alibaba.csp.sentinel.datasource.ConfigParser;
+import com.alibaba.csp.sentinel.datasource.Converter;
-import com.alibaba.csp.sentinel.datasource.DataSource;
 import com.alibaba.csp.sentinel.log.RecordLog;
+
 import com.ctrip.framework.apollo.Config;
 import com.ctrip.framework.apollo.ConfigChangeListener;
 import com.ctrip.framework.apollo.ConfigService;
@@ -14,7 +14,8 @@ import com.google.common.base.Strings;
 import com.google.common.collect.Sets;
 
 /**
- * A {@link DataSource} with <a href="http://github.com/ctripcorp/apollo">Apollo</a> as its configuration source.
+ * A read-only {@code DataSource} with <a href="http://github.com/ctripcorp/apollo">Apollo</a> as its configuration
+ * source.
  * <br />
  * When the rule is changed in Apollo, it will take effect in real time.
  *
@@ -22,73 +23,75 @@ import com.google.common.collect.Sets;
  */
 public class ApolloDataSource<T> extends AbstractDataSource<String, T> {
 
-  private final Config config;
+    private final Config config;
-  private final String flowRulesKey;
+    private final String flowRulesKey;
-  private final String defaultFlowRuleValue;
+    private final String defaultFlowRuleValue;
 
-  /**
+    /**
-   * Constructs the Apollo data source
+     * Constructs the Apollo data source
-   *
+     *
-   * @param namespaceName        the namespace name in Apollo, should not be null or empty
+     * @param namespaceName        the namespace name in Apollo, should not be null or empty
-   * @param flowRulesKey         the flow rules key in the namespace, should not be null or empty
+     * @param flowRulesKey         the flow rules key in the namespace, should not be null or empty
-   * @param defaultFlowRuleValue the default flow rules value when the flow rules key is not found or any error occurred
+     * @param defaultFlowRuleValue the default flow rules value when the flow rules key is not found or any error
-   * @param parser               the parser to transform string configuration to actual flow rules
+     *                             occurred
-   */
+     * @param parser               the parser to transform string configuration to actual flow rules
-  public ApolloDataSource(String namespaceName, String flowRulesKey, String defaultFlowRuleValue,
+     */
-      ConfigParser<String, T> parser) {
+    public ApolloDataSource(String namespaceName, String flowRulesKey, String defaultFlowRuleValue,
-    super(parser);
+                            Converter<String, T> parser) {
+        super(parser);
 
-    Preconditions.checkArgument(!Strings.isNullOrEmpty(namespaceName), "Namespace name could not be null or empty");
+        Preconditions.checkArgument(!Strings.isNullOrEmpty(namespaceName), "Namespace name could not be null or empty");
-    Preconditions.checkArgument(!Strings.isNullOrEmpty(flowRulesKey), "FlowRuleKey could not be null or empty!");
+        Preconditions.checkArgument(!Strings.isNullOrEmpty(flowRulesKey), "FlowRuleKey could not be null or empty!");
 
-    this.flowRulesKey = flowRulesKey;
+        this.flowRulesKey = flowRulesKey;
-    this.defaultFlowRuleValue = defaultFlowRuleValue;
+        this.defaultFlowRuleValue = defaultFlowRuleValue;
 
-    this.config = ConfigService.getConfig(namespaceName);
+        this.config = ConfigService.getConfig(namespaceName);
 
-    initialize();
+        initialize();
 
-    RecordLog.info(String.format("Initialized rule for namespace: %s, flow rules key: %s", namespaceName, flowRulesKey));
+        RecordLog.info(String.format("Initialized rule for namespace: %s, flow rules key: %s",
-  }
+            namespaceName, flowRulesKey));
-
-  private void initialize() {
-    initializeConfigChangeListener();
-    loadAndUpdateRules();
-  }
-
-  private void loadAndUpdateRules() {
-    try {
-      T newValue = loadConfig();
-      if (newValue == null) {
-        RecordLog.warn("[ApolloDataSource] WARN: rule config is null, you may have to check your data source");
-      }
-      getProperty().updateValue(newValue);
-    } catch (Throwable ex) {
-      RecordLog.warn("[ApolloDataSource] Error when loading rule config", ex);
     }
-  }
 
-  private void initializeConfigChangeListener() {
+    private void initialize() {
-    config.addChangeListener(new ConfigChangeListener() {
+        initializeConfigChangeListener();
-      @Override
-      public void onChange(ConfigChangeEvent changeEvent) {
-        ConfigChange change = changeEvent.getChange(flowRulesKey);
-        //change is never null because the listener will only notify for this key
-        if (change != null) {
-          RecordLog.info("[ApolloDataSource] Received config changes: " + change.toString());
-        }
         loadAndUpdateRules();
-      }
+    }
-    }, Sets.newHashSet(flowRulesKey));
-  }
 
-  @Override
+    private void loadAndUpdateRules() {
-  public String readSource() throws Exception {
+        try {
-    return config.getProperty(flowRulesKey, defaultFlowRuleValue);
+            T newValue = loadConfig();
-  }
+            if (newValue == null) {
+                RecordLog.warn("[ApolloDataSource] WARN: rule config is null, you may have to check your data source");
+            }
+            getProperty().updateValue(newValue);
+        } catch (Throwable ex) {
+            RecordLog.warn("[ApolloDataSource] Error when loading rule config", ex);
+        }
+    }
 
-  @Override
+    private void initializeConfigChangeListener() {
-  public void close() throws Exception {
+        config.addChangeListener(new ConfigChangeListener() {
-    // nothing to destroy
+            @Override
-  }
+            public void onChange(ConfigChangeEvent changeEvent) {
+                ConfigChange change = changeEvent.getChange(flowRulesKey);
+                //change is never null because the listener will only notify for this key
+                if (change != null) {
+                    RecordLog.info("[ApolloDataSource] Received config changes: " + change.toString());
+                }
+                loadAndUpdateRules();
+            }
+        }, Sets.newHashSet(flowRulesKey));
+    }
+
+    @Override
+    public String readSource() throws Exception {
+        return config.getProperty(flowRulesKey, defaultFlowRuleValue);
+    }
+
+    @Override
+    public void close() throws Exception {
+        // nothing to destroy
+    }
 }

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

@@ -18,12 +18,20 @@ package com.alibaba.csp.sentinel.datasource;
 import com.alibaba.csp.sentinel.property.DynamicSentinelProperty;
 import com.alibaba.csp.sentinel.property.SentinelProperty;
 
-public abstract class AbstractDataSource<S, T> implements DataSource<S, T> {
+/**
+ * The abstract readable data source provides basic functionality for loading and parsing config.
+ *
+ * @param <S> source data type
+ * @param <T> target data type
+ * @author Carpenter Lee
+ * @author Eric Zhao
+ */
+public abstract class AbstractDataSource<S, T> implements ReadableDataSource<S, T> {
 
-    protected final ConfigParser<S, T> parser;
+    protected final Converter<S, T> parser;
     protected final SentinelProperty<T> property;
 
-    public AbstractDataSource(ConfigParser<S, T> parser) {
+    public AbstractDataSource(Converter<S, T> parser) {
         if (parser == null) {
             throw new IllegalArgumentException("parser can't be null");
         }
@@ -33,13 +41,11 @@ public abstract class AbstractDataSource<S, T> implements DataSource<S, T> {
 
     @Override
     public T loadConfig() throws Exception {
-        S readValue = readSource();
+        return loadConfig(readSource());
-        T value = parser.parse(readValue);
-        return value;
     }
 
     public T loadConfig(S conf) throws Exception {
-        T value = parser.parse(conf);
+        T value = parser.convert(conf);
         return value;
     }
 
@@ -47,10 +53,4 @@ public abstract class AbstractDataSource<S, T> implements DataSource<S, T> {
     public SentinelProperty<T> getProperty() {
         return property;
     }
-
-    @Override
-    public void writeDataSource(T values) throws Exception {
-        throw new UnsupportedOperationException();
-    }
-
 }

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

@@ -23,7 +23,7 @@ import com.alibaba.csp.sentinel.concurrent.NamedThreadFactory;
 import com.alibaba.csp.sentinel.log.RecordLog;
 
 /**
- * A {@link DataSource} automatically fetches the backend data.
+ * A {@link ReadableDataSource} automatically fetches the backend data.
  *
  * @param <S> source data type
  * @param <T> target data type
@@ -34,12 +34,12 @@ public abstract class AutoRefreshDataSource<S, T> extends AbstractDataSource<S,
     private ScheduledExecutorService service;
     protected long recommendRefreshMs = 3000;
 
-    public AutoRefreshDataSource(ConfigParser<S, T> configParser) {
+    public AutoRefreshDataSource(Converter<S, T> configParser) {
         super(configParser);
         startTimerService();
     }
 
-    public AutoRefreshDataSource(ConfigParser<S, T> configParser, final long recommendRefreshMs) {
+    public AutoRefreshDataSource(Converter<S, T> configParser, final long recommendRefreshMs) {
         super(configParser);
         if (recommendRefreshMs <= 0) {
             throw new IllegalArgumentException("recommendRefreshMs must > 0, but " + recommendRefreshMs + " get");
@@ -72,5 +72,4 @@ public abstract class AutoRefreshDataSource<S, T> extends AbstractDataSource<S,
             service = null;
         }
     }
-
 }

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

@@ -16,16 +16,18 @@
 package com.alibaba.csp.sentinel.datasource;
 
 /**
- * Parse config from source data type S to target data type T.
+ * Convert an object from source type {@code S} to target type {@code T}.
  *
  * @author leyou
+ * @author Eric Zhao
  */
-public interface ConfigParser<S, T> {
+public interface Converter<S, T> {
+
     /**
-     * Parse {@code source} to the target format.
+     * Convert {@code source} to the target type.
      *
-     * @param source the source.
+     * @param source the source object
-     * @return the target.
+     * @return the target object
      */
-    T parse(S source);
+    T convert(S source);
 }

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

@@ -19,18 +19,18 @@ import com.alibaba.csp.sentinel.property.NoOpSentinelProperty;
 import com.alibaba.csp.sentinel.property.SentinelProperty;
 
 /**
- * A {@link DataSource} based on nothing. {@link EmptyDataSource#getProperty()} will always return the same cached
+ * A {@link ReadableDataSource} based on nothing. {@link EmptyDataSource#getProperty()} will always return the same cached
  * {@link SentinelProperty} that doing nothing.
  * <br/>
- * This class is used when we want to use default settings instead of configs from the {@link DataSource}
+ * This class is used when we want to use default settings instead of configs from the {@link ReadableDataSource}.
  *
  * @author leyou
  */
-public class EmptyDataSource implements DataSource<Object, Object> {
+public final class EmptyDataSource implements ReadableDataSource<Object, Object> {
 
-    public static final DataSource<Object, Object> EMPTY_DATASOURCE = new EmptyDataSource();
+    public static final ReadableDataSource<Object, Object> EMPTY_DATASOURCE = new EmptyDataSource();
 
-    private static final SentinelProperty<Object> property = new NoOpSentinelProperty();
+    private static final SentinelProperty<Object> PROPERTY = new NoOpSentinelProperty();
 
     private EmptyDataSource() { }
 
@@ -46,15 +46,9 @@ public class EmptyDataSource implements DataSource<Object, Object> {
 
     @Override
     public SentinelProperty<Object> getProperty() {
-        return property;
+        return PROPERTY;
     }
 
     @Override
     public void close() throws Exception { }
-
-    @Override
-    public void writeDataSource(Object config) throws Exception {
-        throw new UnsupportedOperationException();
-    }
-
 }

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

@@ -25,16 +25,17 @@ import com.alibaba.csp.sentinel.log.RecordLog;
 
 /**
  * <p>
- * A {@link DataSource} based on file. This class will automatically fetches the backend file every 3 seconds.
+ * A {@link WritableDataSource} based on file. This class will automatically fetches the backend file every refresh period.
  * </p>
  * <p>
- * Limitations: default read buffer size is 1MB, if file size is greater than buffer size, exceeding bytes will
+ * Limitations: Default read buffer size is 1 MB. If file size is greater than buffer size, exceeding bytes will
- * be ignored. Default charset is UTF8.
+ * be ignored. Default charset is UTF-8.
  * </p>
  *
  * @author Carpenter Lee
+ * @author Eric Zhao
  */
-public class FileRefreshableDataSource<T> extends AutoRefreshDataSource<String, T> {
+public class FileRefreshableDataSource<T> extends AutoRefreshDataSource<String, T> implements WritableDataSource<T> {
 
     private static final int MAX_SIZE = 1024 * 1024 * 4;
     private static final long DEFAULT_REFRESH_MS = 3000;
@@ -42,37 +43,38 @@ public class FileRefreshableDataSource<T> extends AutoRefreshDataSource<String,
     private static final Charset DEFAULT_CHAR_SET = Charset.forName("utf-8");
 
     private byte[] buf;
-    private Charset charset;
+    private final Charset charset;
-    private File file;
+    private final File file;
+
+    private final Converter<T, String> configEncoder;
 
     /**
-     * Create a file based {@link DataSource} whose read buffer size is 1MB, charset is UTF8,
+     * Create a file based {@link ReadableDataSource} whose read buffer size is 1MB, charset is UTF8,
      * and read interval is 3 seconds.
      *
-     * @param file         the file to read.
+     * @param file         the file to read
-     * @param configParser the config parser.
+     * @param configParser the config decoder (parser)
      */
-    public FileRefreshableDataSource(File file, ConfigParser<String, T> configParser) throws FileNotFoundException {
+    public FileRefreshableDataSource(File file, Converter<String, T> configParser, Converter<T, String> configEncoder) throws FileNotFoundException {
-        this(file, configParser, DEFAULT_REFRESH_MS, DEFAULT_BUF_SIZE, DEFAULT_CHAR_SET);
+        this(file, configParser, configEncoder, DEFAULT_REFRESH_MS, DEFAULT_BUF_SIZE, DEFAULT_CHAR_SET);
     }
 
-    public FileRefreshableDataSource(String fileName, ConfigParser<String, T> configParser)
+    public FileRefreshableDataSource(String fileName, Converter<String, T> configParser, Converter<T, String> configEncoder)
         throws FileNotFoundException {
-        this(new File(fileName), configParser, DEFAULT_REFRESH_MS, DEFAULT_BUF_SIZE, DEFAULT_CHAR_SET);
+        this(new File(fileName), configParser, configEncoder, DEFAULT_REFRESH_MS, DEFAULT_BUF_SIZE, DEFAULT_CHAR_SET);
-        //System.out.println(file.getAbsoluteFile());
     }
 
-    public FileRefreshableDataSource(File file, ConfigParser<String, T> configParser, int bufSize)
+    public FileRefreshableDataSource(File file, Converter<String, T> configParser, Converter<T, String> configEncoder, int bufSize)
         throws FileNotFoundException {
-        this(file, configParser, DEFAULT_REFRESH_MS, bufSize, DEFAULT_CHAR_SET);
+        this(file, configParser, configEncoder, DEFAULT_REFRESH_MS, bufSize, DEFAULT_CHAR_SET);
     }
 
-    public FileRefreshableDataSource(File file, ConfigParser<String, T> configParser, Charset charset)
+    public FileRefreshableDataSource(File file, Converter<String, T> configParser, Converter<T, String> configEncoder, Charset charset)
         throws FileNotFoundException {
-        this(file, configParser, DEFAULT_REFRESH_MS, DEFAULT_BUF_SIZE, charset);
+        this(file, configParser, configEncoder, DEFAULT_REFRESH_MS, DEFAULT_BUF_SIZE, charset);
     }
 
-    public FileRefreshableDataSource(File file, ConfigParser<String, T> configParser, long recommendRefreshMs,
+    public FileRefreshableDataSource(File file, Converter<String, T> configParser, Converter<T, String> configEncoder, long recommendRefreshMs,
                                      int bufSize, Charset charset) throws FileNotFoundException {
         super(configParser, recommendRefreshMs);
         if (bufSize <= 0 || bufSize > MAX_SIZE) {
@@ -84,9 +86,13 @@ public class FileRefreshableDataSource<T> extends AutoRefreshDataSource<String,
         if (charset == null) {
             throw new IllegalArgumentException("charset can't be null");
         }
+        if (configEncoder == null) {
+            throw new IllegalArgumentException("Config encoder cannot be null");
+        }
         this.buf = new byte[bufSize];
         this.file = file;
         this.charset = charset;
+        this.configEncoder = configEncoder;
         firstLoad();
     }
 
@@ -106,7 +112,7 @@ public class FileRefreshableDataSource<T> extends AutoRefreshDataSource<String,
             inputStream = new FileInputStream(file);
             FileChannel channel = inputStream.getChannel();
             if (channel.size() > buf.length) {
-                throw new RuntimeException(file.getAbsolutePath() + " file size=" + channel.size()
+                throw new IllegalStateException(file.getAbsolutePath() + " file size=" + channel.size()
                     + ", is bigger than bufSize=" + buf.length + ". Can't read");
             }
             int len = inputStream.read(buf);
@@ -128,7 +134,7 @@ public class FileRefreshableDataSource<T> extends AutoRefreshDataSource<String,
     }
 
     @Override
-    public void writeDataSource(T values) throws Exception {
+    public void write(T value) throws Exception {
-        throw new UnsupportedOperationException();
+        throw new UnsupportedOperationException("Not implemented");
     }
 }

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

@@ -18,19 +18,20 @@ package com.alibaba.csp.sentinel.datasource;
 import com.alibaba.csp.sentinel.property.SentinelProperty;
 
 /**
- * This class is responsible for getting configs.
+ * The readable data source is responsible for retrieving configs (read-only).
  *
  * @param <S> source data type
  * @param <T> target data type
  * @author leyou
+ * @author Eric Zhao
  */
-public interface DataSource<S, T> {
+public interface ReadableDataSource<S, T> {
 
     /**
      * Load data data source as the target type.
      *
      * @return the target data.
-     * @throws Exception
+     * @throws Exception IO or other error occurs
      */
     T loadConfig() throws Exception;
 
@@ -38,7 +39,7 @@ public interface DataSource<S, T> {
      * Read original data from the data source.
      *
      * @return the original data.
-     * @throws Exception
+     * @throws Exception IO or other error occurs
      */
     S readSource() throws Exception;
 
@@ -49,18 +50,10 @@ public interface DataSource<S, T> {
      */
     SentinelProperty<T> getProperty();
 
-    /**
-     * Write the {@code values} to the data source.
-     *
-     * @param values
-     * @throws Exception
-     */
-    void writeDataSource(T values) throws Exception;
-
     /**
      * Close the data source.
      *
-     * @throws Exception
+     * @throws Exception IO or other error occurs
      */
     void close() throws Exception;
 }

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

@@ -0,0 +1,33 @@
+/*
+ * 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;
+
+/**
+ * Interface of writable data source support.
+ *
+ * @author Eric Zhao
+ * @since 0.2.0
+ */
+public interface WritableDataSource<T> {
+
+    /**
+     * Write the {@code value} to the data source.
+     *
+     * @param value value to write
+     * @throws Exception IO or other error occurs
+     */
+    void write(T value) throws Exception;
+}

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

@@ -19,7 +19,7 @@ For instance:
 ```java
 // remoteAddress is the address of Nacos
 // groupId and dataId are concepts of Nacos
-DataSource<String, List<FlowRule>> flowRuleDataSource = new NacosDataSource<>(remoteAddress, groupId, dataId,
+ReadableDataSource<String, List<FlowRule>> flowRuleDataSource = new NacosDataSource<>(remoteAddress, groupId, dataId,
     source -> JSON.parseObject(source, new TypeReference<List<FlowRule>>() {}));
 FlowRuleManager.register2Property(flowRuleDataSource.getProperty());
 ```

sentinel-extension/sentinel-datasource-nacos/src/main/java/com/alibaba/csp/sentinel/datasource/nacos/NacosDataSource.java

@@ -23,8 +23,7 @@ import java.util.concurrent.TimeUnit;
 
 import com.alibaba.csp.sentinel.concurrent.NamedThreadFactory;
 import com.alibaba.csp.sentinel.datasource.AbstractDataSource;
-import com.alibaba.csp.sentinel.datasource.ConfigParser;
+import com.alibaba.csp.sentinel.datasource.Converter;
-import com.alibaba.csp.sentinel.datasource.DataSource;
 import com.alibaba.csp.sentinel.log.RecordLog;
 import com.alibaba.csp.sentinel.util.StringUtil;
 import com.alibaba.nacos.api.NacosFactory;
@@ -32,7 +31,7 @@ import com.alibaba.nacos.api.config.ConfigService;
 import com.alibaba.nacos.api.config.listener.Listener;
 
 /**
- * A {@link DataSource} with Nacos backend. When the data in Nacos backend has been modified,
+ * A read-only {@code DataSource} with Nacos backend. When the data in Nacos backend has been modified,
  * Nacos will automatically push the new value so that the dynamic configuration can be real-time.
  *
  * @author Eric Zhao
@@ -58,7 +57,7 @@ public class NacosDataSource<T> extends AbstractDataSource<String, T> {
     private ConfigService configService = null;
 
     /**
-     * Constructs an DataSource with Nacos backend.
+     * Constructs an read-only DataSource with Nacos backend.
      *
      * @param serverAddr server address of Nacos, cannot be empty
      * @param groupId    group ID, cannot be empty
@@ -66,7 +65,7 @@ public class NacosDataSource<T> extends AbstractDataSource<String, T> {
      * @param parser     customized data parser, cannot be empty
      */
     public NacosDataSource(final String serverAddr, final String groupId, final String dataId,
-                           ConfigParser<String, T> parser) {
+                           Converter<String, T> parser) {
         super(parser);
         if (StringUtil.isBlank(serverAddr) || StringUtil.isBlank(groupId) || StringUtil.isBlank(dataId)) {
             throw new IllegalArgumentException(String.format("Bad argument: serverAddr=[%s], groupId=[%s], dataId=[%s]",
@@ -84,7 +83,7 @@ public class NacosDataSource<T> extends AbstractDataSource<String, T> {
             public void receiveConfigInfo(final String configInfo) {
                 RecordLog.info(String.format("[NacosDataSource] New property value received for (%s, %s, %s): %s",
                     serverAddr, dataId, groupId, configInfo));
-                T newValue = NacosDataSource.this.parser.parse(configInfo);
+                T newValue = NacosDataSource.this.parser.convert(configInfo);
                 // Update the new value to the property.
                 getProperty().updateValue(newValue);
             }
@@ -97,11 +96,11 @@ public class NacosDataSource<T> extends AbstractDataSource<String, T> {
         try {
             T newValue = loadConfig();
             if (newValue == null) {
-                RecordLog.info("[NacosDataSource] WARN: initial config is null, you may have to check your data source");
+                RecordLog.warn("[NacosDataSource] WARN: initial config is null, you may have to check your data source");
             }
             getProperty().updateValue(newValue);
         } catch (Exception ex) {
-            RecordLog.info("[NacosDataSource] Error when loading initial config", ex);
+            RecordLog.warn("[NacosDataSource] Error when loading initial config", ex);
         }
     }
 
@@ -111,7 +110,7 @@ public class NacosDataSource<T> extends AbstractDataSource<String, T> {
             // Add config listener.
             configService.addListener(dataId, groupId, configListener);
         } catch (Exception e) {
-            RecordLog.info("[NacosDataSource] Error occurred when initializing Nacos data source", e);
+            RecordLog.warn("[NacosDataSource] Error occurred when initializing Nacos data source", e);
             e.printStackTrace();
         }
     }

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

@@ -18,7 +18,7 @@ For instance:
 
 ```java
 // `path` is the data path in ZooKeeper
-DataSource<String, List<FlowRule>> flowRuleDataSource = new ZookeeperDataSource<>(remoteAddress, path, source -> JSON.parseObject(source, new TypeReference<List<FlowRule>>() {}));
+ReadableDataSource<String, List<FlowRule>> flowRuleDataSource = new ZookeeperDataSource<>(remoteAddress, path, source -> JSON.parseObject(source, new TypeReference<List<FlowRule>>() {}));
 FlowRuleManager.register2Property(flowRuleDataSource.getProperty());
 ```
 

sentinel-extension/sentinel-datasource-zookeeper/src/main/java/com/alibaba/csp/sentinel/datasource/zookeeper/ZookeeperDataSource.java

@@ -7,7 +7,7 @@ import java.util.concurrent.TimeUnit;
 
 import com.alibaba.csp.sentinel.concurrent.NamedThreadFactory;
 import com.alibaba.csp.sentinel.datasource.AbstractDataSource;
-import com.alibaba.csp.sentinel.datasource.ConfigParser;
+import com.alibaba.csp.sentinel.datasource.Converter;
 import com.alibaba.csp.sentinel.log.RecordLog;
 import com.alibaba.csp.sentinel.util.StringUtil;
 
@@ -21,7 +21,7 @@ import org.apache.zookeeper.CreateMode;
 import org.apache.zookeeper.data.Stat;
 
 /**
- * Zookeeper DataSource
+ * A read-only {@code DataSource} with ZooKeeper backend.
  *
  * @author guonanjun
  */
@@ -40,7 +40,7 @@ public class ZookeeperDataSource<T> extends AbstractDataSource<String, T> {
     private CuratorFramework zkClient = null;
     private NodeCache nodeCache = null;
 
-    public ZookeeperDataSource(final String serverAddr, final String path, ConfigParser<String, T> parser) {
+    public ZookeeperDataSource(final String serverAddr, final String path, Converter<String, T> parser) {
         super(parser);
         if (StringUtil.isBlank(serverAddr) || StringUtil.isBlank(path)) {
             throw new IllegalArgumentException(String.format("Bad argument: serverAddr=[%s], path=[%s]", serverAddr, path));
@@ -54,7 +54,7 @@ public class ZookeeperDataSource<T> extends AbstractDataSource<String, T> {
      * This constructor is Nacos-style.
      */
     public ZookeeperDataSource(final String serverAddr, final String groupId, final String dataId,
-                               ConfigParser<String, T> parser) {
+                               Converter<String, T> parser) {
         super(parser);
         if (StringUtil.isBlank(serverAddr) || StringUtil.isBlank(groupId) || StringUtil.isBlank(dataId)) {
             throw new IllegalArgumentException(String.format("Bad argument: serverAddr=[%s], groupId=[%s], dataId=[%s]", serverAddr, groupId, dataId));
@@ -73,11 +73,11 @@ public class ZookeeperDataSource<T> extends AbstractDataSource<String, T> {
         try {
             T newValue = loadConfig();
             if (newValue == null) {
-                RecordLog.info("[ZookeeperDataSource] WARN: initial config is null, you may have to check your data source");
+                RecordLog.warn("[ZookeeperDataSource] WARN: initial config is null, you may have to check your data source");
             }
             getProperty().updateValue(newValue);
         } catch (Exception ex) {
-            RecordLog.info("[ZookeeperDataSource] Error when loading initial config", ex);
+            RecordLog.warn("[ZookeeperDataSource] Error when loading initial config", ex);
         }
     }
 
@@ -95,7 +95,7 @@ public class ZookeeperDataSource<T> extends AbstractDataSource<String, T> {
                     }
                     RecordLog.info(String.format("[ZookeeperDataSource] New property value received for (%s, %s): %s",
                         serverAddr, path, configInfo));
-                    T newValue = ZookeeperDataSource.this.parser.parse(configInfo);
+                    T newValue = ZookeeperDataSource.this.parser.convert(configInfo);
                     // Update the new value to the property.
                     getProperty().updateValue(newValue);
                 }
@@ -112,7 +112,7 @@ public class ZookeeperDataSource<T> extends AbstractDataSource<String, T> {
             this.nodeCache.getListenable().addListener(this.listener, this.pool);
             this.nodeCache.start();
         } catch (Exception e) {
-            RecordLog.info("[ZookeeperDataSource] Error occurred when initializing Zookeeper data source", e);
+            RecordLog.warn("[ZookeeperDataSource] Error occurred when initializing Zookeeper data source", e);
             e.printStackTrace();
         }
     }

sentinel-extension/sentinel-datasource-zookeeper/src/test/java/com/alibaba/csp/sentinel/datasource/zookeeper/ZookeeperDataSourceTest.java

@@ -3,8 +3,8 @@ package com.alibaba.csp.sentinel.datasource.zookeeper;
 import java.util.Collections;
 import java.util.List;
 
-import com.alibaba.csp.sentinel.datasource.ConfigParser;
+import com.alibaba.csp.sentinel.datasource.Converter;
-import com.alibaba.csp.sentinel.datasource.DataSource;
+import com.alibaba.csp.sentinel.datasource.ReadableDataSource;
 import com.alibaba.csp.sentinel.slots.block.RuleConstant;
 import com.alibaba.csp.sentinel.slots.block.flow.FlowRule;
 import com.alibaba.csp.sentinel.slots.block.flow.FlowRuleManager;
@@ -34,10 +34,10 @@ public class ZookeeperDataSourceTest {
         final String remoteAddress = server.getConnectString();
         final String path = "/sentinel-zk-ds-demo/flow-HK";
 
-        DataSource<String, List<FlowRule>> flowRuleDataSource = new ZookeeperDataSource<List<FlowRule>>(remoteAddress, path,
+        ReadableDataSource<String, List<FlowRule>> flowRuleDataSource = new ZookeeperDataSource<List<FlowRule>>(remoteAddress, path,
-            new ConfigParser<String, List<FlowRule>>() {
+            new Converter<String, List<FlowRule>>() {
                 @Override
-                public List<FlowRule> parse(String source) {
+                public List<FlowRule> convert(String source) {
                     return JSON.parseObject(source, new TypeReference<List<FlowRule>>() {});
                 }
             });