init

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

@@ -0,0 +1,31 @@
+<?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>1.8.3</version>
+  </parent>
+  <modelVersion>4.0.0</modelVersion>
+
+  <artifactId>sentinel-datasource-apollo</artifactId>
+
+  <properties>
+    <apollo.version>1.5.0</apollo.version>
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>com.alibaba.csp</groupId>
+      <artifactId>sentinel-datasource-extension</artifactId>
+    </dependency>
+
+    <dependency>
+      <groupId>com.ctrip.framework.apollo</groupId>
+      <artifactId>apollo-client</artifactId>
+      <version>${apollo.version}</version>
+    </dependency>
+  </dependencies>
+
+</project>

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

@@ -0,0 +1,100 @@
+package com.alibaba.csp.sentinel.datasource.apollo;
+
+import com.alibaba.csp.sentinel.datasource.AbstractDataSource;
+import com.alibaba.csp.sentinel.datasource.Converter;
+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;
+import com.ctrip.framework.apollo.model.ConfigChange;
+import com.ctrip.framework.apollo.model.ConfigChangeEvent;
+import com.google.common.base.Preconditions;
+import com.google.common.base.Strings;
+import com.google.common.collect.Sets;
+
+/**
+ * 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.
+ *
+ * @author Jason Song
+ * @author Haojun Ren
+ */
+public class ApolloDataSource<T> extends AbstractDataSource<String, T> {
+
+    private final Config config;
+    private final String ruleKey;
+    private final String defaultRuleValue;
+
+    private ConfigChangeListener configChangeListener;
+
+    /**
+     * Constructs the Apollo data source
+     *
+     * @param namespaceName        the namespace name in Apollo, should not be null or empty
+     * @param ruleKey              the rule key in the namespace, should not be null or empty
+     * @param defaultRuleValue     the default rule value when the ruleKey is not found or any error
+     *                             occurred
+     * @param parser               the parser to transform string configuration to actual flow rules
+     */
+    public ApolloDataSource(String namespaceName, String ruleKey, String defaultRuleValue,
+                            Converter<String, T> parser) {
+        super(parser);
+
+        Preconditions.checkArgument(!Strings.isNullOrEmpty(namespaceName), "Namespace name could not be null or empty");
+        Preconditions.checkArgument(!Strings.isNullOrEmpty(ruleKey), "RuleKey could not be null or empty!");
+
+        this.ruleKey = ruleKey;
+        this.defaultRuleValue = defaultRuleValue;
+
+        this.config = ConfigService.getConfig(namespaceName);
+
+        initialize();
+
+        RecordLog.info("Initialized rule for namespace: {}, rule key: {}", namespaceName, ruleKey);
+    }
+
+    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() {
+        configChangeListener = new ConfigChangeListener() {
+            @Override
+            public void onChange(ConfigChangeEvent changeEvent) {
+                ConfigChange change = changeEvent.getChange(ruleKey);
+                //change is never null because the listener will only notify for this key
+                if (change != null) {
+                    RecordLog.info("[ApolloDataSource] Received config changes: {}", change);
+                }
+                loadAndUpdateRules();
+            }
+        };
+        config.addChangeListener(configChangeListener, Sets.newHashSet(ruleKey));
+    }
+
+    @Override
+    public String readSource() throws Exception {
+        return config.getProperty(ruleKey, defaultRuleValue);
+    }
+
+    @Override
+    public void close() throws Exception {
+        config.removeChangeListener(configChangeListener);
+    }
+}