Add FileInJarReadableDataSource to support reading config file in jar (#646)

sentinel-demo/sentinel-demo-dynamic-file-rule/src/main/java/com/alibaba/csp/sentinel/demo/file/rule/JarFileDataSourceDemo.java

@@ -0,0 +1,70 @@
+package com.alibaba.csp.sentinel.demo.file.rule;
+
+import com.alibaba.csp.sentinel.datasource.Converter;
+import com.alibaba.csp.sentinel.datasource.FileInJarReadableDataSource;
+import com.alibaba.csp.sentinel.datasource.ReadableDataSource;
+import com.alibaba.csp.sentinel.property.PropertyListener;
+import com.alibaba.csp.sentinel.property.SentinelProperty;
+import com.alibaba.csp.sentinel.slots.block.Rule;
+import com.alibaba.csp.sentinel.slots.block.degrade.DegradeRuleManager;
+import com.alibaba.csp.sentinel.slots.block.flow.FlowRule;
+import com.alibaba.csp.sentinel.slots.block.flow.FlowRuleManager;
+import com.alibaba.csp.sentinel.slots.system.SystemRuleManager;
+import com.alibaba.fastjson.JSON;
+import com.alibaba.fastjson.TypeReference;
+
+import java.util.List;
+
+/**
+ * <p>
+ * This Demo shows how to use {@link FileInJarReadableDataSource} to read {@link Rule}s from jarfile. The
+ * {@link FileInJarReadableDataSource} will automatically fetches the backend file every 3 seconds, and
+ * inform the listener if the file is updated.
+ * </p>
+ * <p>
+ * Each {@link ReadableDataSource} has a {@link SentinelProperty} to hold the deserialized config data.
+ * {@link PropertyListener} will listen to the {@link SentinelProperty} instead of the datasource.
+ * {@link Converter} is used for telling how to deserialize the data.
+ * </p>
+ * <p>
+ * {@link FlowRuleManager#register2Property(SentinelProperty)},
+ * {@link DegradeRuleManager#register2Property(SentinelProperty)},
+ * {@link SystemRuleManager#register2Property(SentinelProperty)} could be called for listening the
+ * {@link Rule}s change.
+ * </p>
+ * <p>
+ * For other kinds of data source, such as <a href="https://github.com/alibaba/nacos">Nacos</a>,
+ * Zookeeper, Git, or even CSV file, We could implement {@link ReadableDataSource} interface to read these
+ * configs.
+ * </p>
+ *
+ * @author dingq
+ * @date 2019-03-30
+ */
+public class JarFileDataSourceDemo {
+    public static void main(String[] args) throws Exception {
+        JarFileDataSourceDemo demo = new JarFileDataSourceDemo();
+        demo.listenRules();
+
+        /*
+         * Start to require tokens, rate will be limited by rule in FlowRule.json
+         */
+        FlowQpsRunner runner = new FlowQpsRunner();
+        runner.simulateTraffic();
+        runner.tick();
+    }
+
+    private void listenRules() throws Exception {
+        String jarPath = System.getProperty("user.dir") + "/sentinel-demo/sentinel-demo-dynamic-file-rule/target/sentinel-demo-dynamic-file-rule-1.5.1-SNAPSHOT.jar";
+        // eg: if flowRuleInJarName full path is 'sentinel-demo-dynamic-file-rule-1.5.1-SNAPSHOT.jar!/classes/FlowRule.json',
+        // your flowRuleInJarName is 'classes/FlowRule.json'
+        String flowRuleInJarPath = "FlowRule.json";
+
+        FileInJarReadableDataSource<List<FlowRule>> flowRuleDataSource = new FileInJarReadableDataSource<>(
+                jarPath,flowRuleInJarPath, flowRuleListParser);
+        FlowRuleManager.register2Property(flowRuleDataSource.getProperty());
+    }
+
+    private Converter<String, List<FlowRule>> flowRuleListParser = source -> JSON.parseObject(source,
+            new TypeReference<List<FlowRule>>() {});
+}

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

@@ -0,0 +1,140 @@
+/*
+ * 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;
+
+import com.alibaba.csp.sentinel.log.RecordLog;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.charset.Charset;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+
+/**
+ * <p>
+ * A {@link ReadableDataSource} based on jarfile. This class can only read file when it
+ * run but  will not automatically refresh if it is changed.
+ * </p>
+ * <p>
+ * Limitations: Default read buffer size is 1 MB. If file size is greater than
+ * buffer size, exceeding bytes will be ignored. Default charset is UTF-8.
+ * </p>
+ *
+ * @author dingq
+ * @date 2019-03-30
+ */
+public class FileInJarReadableDataSource<T> extends AutoRefreshDataSource<String, T> {
+    private static final int MAX_SIZE = 1024 * 1024 * 4;
+    private static final long DEFAULT_REFRESH_MS = 3000;
+    private static final int DEFAULT_BUF_SIZE = 1024 * 1024;
+    private static final Charset DEFAULT_CHAR_SET = Charset.forName("utf-8");
+
+    private byte[] buf;
+    private JarEntry jarEntry;
+    private JarFile jarFile;
+    private final Charset charset;
+    private final String jarName;
+    private final String fileInJarName;
+
+    /**
+     * @param jarName      the jar to read
+     * @param fileInJarName     the file in jar to read
+     * @param configParser the config decoder (parser)
+     * @throws FileNotFoundException
+     */
+    public FileInJarReadableDataSource(String jarName, String fileInJarName, Converter<String, T> configParser)
+            throws IOException {
+        this(jarName, fileInJarName, configParser, DEFAULT_REFRESH_MS, DEFAULT_BUF_SIZE, DEFAULT_CHAR_SET);
+    }
+
+    public FileInJarReadableDataSource(String jarName, String fileInJarName, Converter<String, T> configParser, int bufSize)
+            throws IOException {
+        this(jarName, fileInJarName, configParser, DEFAULT_REFRESH_MS, bufSize, DEFAULT_CHAR_SET);
+    }
+
+    public FileInJarReadableDataSource(String jarName, String fileInJarName, Converter<String, T> configParser, Charset charset)
+            throws IOException {
+        this(jarName, fileInJarName, configParser, DEFAULT_REFRESH_MS, DEFAULT_BUF_SIZE, charset);
+    }
+
+    public FileInJarReadableDataSource(String jarName, String fileInJarName, Converter<String, T> configParser, long recommendRefreshMs, int bufSize,
+                                       Charset charset) throws IOException {
+        super(configParser, recommendRefreshMs);
+        if (bufSize <= 0 || bufSize > MAX_SIZE) {
+            throw new IllegalArgumentException("bufSize must between (0, " + MAX_SIZE + "], but " + bufSize + " get");
+        }
+        if (charset == null) {
+            throw new IllegalArgumentException("charset can't be null");
+        }
+        this.buf = new byte[bufSize];
+        this.charset = charset;
+        this.jarName = jarName;
+        this.fileInJarName = fileInJarName;
+        refreshJar();
+        firstLoad();
+    }
+
+    @Override
+    public String readSource() throws Exception {
+        if (null == jarEntry) {
+            // Will throw FileNotFoundException later.
+            RecordLog.warn(String.format("[FileInJarReadableDataSource] File does not exist: %s", jarFile.getName()));
+        }
+        InputStream inputStream = null;
+        try {
+            inputStream = jarFile.getInputStream(jarEntry);
+            if (inputStream.available() > buf.length) {
+                throw new IllegalStateException(jarFile.getName() + " file size=" + inputStream.available()
+                        + ", is bigger than bufSize=" + buf.length + ". Can't read");
+            }
+            int len = inputStream.read(buf);
+            return new String(buf, 0, len, charset);
+        } finally {
+            if (inputStream != null) {
+                try {
+                    inputStream.close();
+                } catch (Exception ignore) {
+                }
+            }
+        }
+
+    }
+
+    @Override
+    protected boolean isModified() {
+        return false;
+    }
+
+    private void firstLoad() {
+        try {
+            T newValue = loadConfig();
+            getProperty().updateValue(newValue);
+        } catch (Throwable e) {
+            RecordLog.info("loadConfig exception", e);
+        }
+    }
+
+    @Override
+    public void close() throws Exception {
+        super.close();
+        buf = null;
+    }
+
+    private void refreshJar() throws IOException {
+        this.jarFile = new JarFile(jarName);
+        this.jarEntry = jarFile.getJarEntry(fileInJarName);
+    }
+}