kafka Plugins 源码
kafka Plugins 代码
文件路径：/connect/runtime/src/main/java/org/apache/kafka/connect/runtime/isolation/Plugins.java
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.kafka.connect.runtime.isolation;
import org.apache.kafka.common.Configurable;
import org.apache.kafka.common.config.AbstractConfig;
import org.apache.kafka.common.config.provider.ConfigProvider;
import org.apache.kafka.common.utils.Utils;
import org.apache.kafka.connect.components.Versioned;
import org.apache.kafka.connect.connector.Connector;
import org.apache.kafka.connect.connector.Task;
import org.apache.kafka.connect.errors.ConnectException;
import org.apache.kafka.connect.runtime.WorkerConfig;
import org.apache.kafka.connect.sink.SinkConnector;
import org.apache.kafka.connect.source.SourceConnector;
import org.apache.kafka.connect.storage.Converter;
import org.apache.kafka.connect.storage.ConverterConfig;
import org.apache.kafka.connect.storage.ConverterType;
import org.apache.kafka.connect.storage.HeaderConverter;
import org.apache.kafka.connect.transforms.Transformation;
import org.apache.kafka.connect.transforms.predicates.Predicate;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Set;
public class Plugins {
public enum ClassLoaderUsage {
CURRENT_CLASSLOADER,
PLUGINS
}
private static final Logger log = LoggerFactory.getLogger(Plugins.class);
private final DelegatingClassLoader delegatingLoader;
public Plugins(Map<String, String> props) {
List<String> pluginLocations = WorkerConfig.pluginLocations(props);
delegatingLoader = newDelegatingClassLoader(pluginLocations);
delegatingLoader.initLoaders();
}
protected DelegatingClassLoader newDelegatingClassLoader(final List<String> paths) {
return AccessController.doPrivileged(
(PrivilegedAction<DelegatingClassLoader>) () -> new DelegatingClassLoader(paths)
);
}
private static <T> String pluginNames(Collection<PluginDesc<T>> plugins) {
return Utils.join(plugins, ", ");
}
protected static <T> T newPlugin(Class<T> klass) {
// KAFKA-8340: The thread classloader is used during static initialization and must be
// set to the plugin's classloader during instantiation
ClassLoader savedLoader = compareAndSwapLoaders(klass.getClassLoader());
try {
return Utils.newInstance(klass);
} catch (Throwable t) {
throw new ConnectException("Instantiation error", t);
} finally {
compareAndSwapLoaders(savedLoader);
}
}
@SuppressWarnings("unchecked")
protected <U> Class<? extends U> pluginClassFromConfig(
AbstractConfig config,
String propertyName,
Class<U> pluginClass,
Collection<PluginDesc<U>> plugins
) {
Class<?> klass = config.getClass(propertyName);
if (pluginClass.isAssignableFrom(klass)) {
return (Class<? extends U>) klass;
}
throw new ConnectException(
"Failed to find any class that implements " + pluginClass.getSimpleName()
+ " for the config "
+ propertyName + ", available classes are: "
+ pluginNames(plugins)
);
}
@SuppressWarnings("unchecked")
protected static <U> Class<? extends U> pluginClass(
DelegatingClassLoader loader,
String classOrAlias,
Class<U> pluginClass
) throws ClassNotFoundException {
Class<?> klass = loader.loadClass(classOrAlias, false);
if (pluginClass.isAssignableFrom(klass)) {
return (Class<? extends U>) klass;
}
throw new ClassNotFoundException(
"Requested class: "
+ classOrAlias
+ " does not extend " + pluginClass.getSimpleName()
);
}
public static ClassLoader compareAndSwapLoaders(ClassLoader loader) {
ClassLoader current = Thread.currentThread().getContextClassLoader();
if (!current.equals(loader)) {
Thread.currentThread().setContextClassLoader(loader);
}
return current;
}
public ClassLoader currentThreadLoader() {
return Thread.currentThread().getContextClassLoader();
}
public ClassLoader compareAndSwapWithDelegatingLoader() {
ClassLoader current = Thread.currentThread().getContextClassLoader();
if (!current.equals(delegatingLoader)) {
Thread.currentThread().setContextClassLoader(delegatingLoader);
}
return current;
}
public ClassLoader compareAndSwapLoaders(Connector connector) {
ClassLoader connectorLoader = delegatingLoader.connectorLoader(connector);
return compareAndSwapLoaders(connectorLoader);
}
public LoaderSwap withClassLoader(ClassLoader loader) {
ClassLoader savedLoader = compareAndSwapLoaders(loader);
try {
return new LoaderSwap(savedLoader);
} catch (Throwable t) {
compareAndSwapLoaders(savedLoader);
throw t;
}
}
public DelegatingClassLoader delegatingLoader() {
return delegatingLoader;
}
public Set<PluginDesc<SinkConnector>> sinkConnectors() {
return delegatingLoader.sinkConnectors();
}
public Set<PluginDesc<SourceConnector>> sourceConnectors() {
return delegatingLoader.sourceConnectors();
}
public Set<PluginDesc<Converter>> converters() {
return delegatingLoader.converters();
}
public Set<PluginDesc<HeaderConverter>> headerConverters() {
return delegatingLoader.headerConverters();
}
public Set<PluginDesc<Transformation<?>>> transformations() {
return delegatingLoader.transformations();
}
public Set<PluginDesc<Predicate<?>>> predicates() {
return delegatingLoader.predicates();
}
public Object newPlugin(String classOrAlias) throws ClassNotFoundException {
Class<?> klass = pluginClass(delegatingLoader, classOrAlias, Object.class);
return newPlugin(klass);
}
public Connector newConnector(String connectorClassOrAlias) {
Class<? extends Connector> klass = connectorClass(connectorClassOrAlias);
return newPlugin(klass);
}
public Class<? extends Connector> connectorClass(String connectorClassOrAlias) {
Class<? extends Connector> klass;
try {
klass = pluginClass(
delegatingLoader,
connectorClassOrAlias,
Connector.class
);
} catch (ClassNotFoundException e) {
List<PluginDesc<? extends Connector>> matches = new ArrayList<>();
Set<PluginDesc<Connector>> connectors = delegatingLoader.connectors();
for (PluginDesc<? extends Connector> plugin : connectors) {
Class<?> pluginClass = plugin.pluginClass();
String simpleName = pluginClass.getSimpleName();
if (simpleName.equals(connectorClassOrAlias)
|| simpleName.equals(connectorClassOrAlias + "Connector")) {
matches.add(plugin);
}
}
if (matches.isEmpty()) {
throw new ConnectException(
"Failed to find any class that implements Connector and which name matches "
+ connectorClassOrAlias
+ ", available connectors are: "
+ Utils.join(connectors, ", ")
);
}
if (matches.size() > 1) {
throw new ConnectException(
"More than one connector matches alias "
+ connectorClassOrAlias
+ ". Please use full package and class name instead. Classes found: "
+ Utils.join(connectors, ", ")
);
}
PluginDesc<? extends Connector> entry = matches.get(0);
klass = entry.pluginClass();
}
return klass;
}
public Task newTask(Class<? extends Task> taskClass) {
return newPlugin(taskClass);
}
/**
* If the given configuration defines a {@link Converter} using the named configuration property, return a new configured instance.
*
* @param config the configuration containing the {@link Converter}'s configuration; may not be null
* @param classPropertyName the name of the property that contains the name of the {@link Converter} class; may not be null
* @param classLoaderUsage which classloader should be used
* @return the instantiated and configured {@link Converter}; null if the configuration did not define the specified property
* @throws ConnectException if the {@link Converter} implementation class could not be found
*/
public Converter newConverter(AbstractConfig config, String classPropertyName, ClassLoaderUsage classLoaderUsage) {
if (!config.originals().containsKey(classPropertyName)) {
// This configuration does not define the converter via the specified property name
return null;
}
Class<? extends Converter> klass = null;
switch (classLoaderUsage) {
case CURRENT_CLASSLOADER:
// Attempt to load first with the current classloader, and plugins as a fallback.
// Note: we can't use config.getConfiguredInstance because Converter doesn't implement Configurable, and even if it did
// we have to remove the property prefixes before calling config(...) and we still always want to call Converter.config.
klass = pluginClassFromConfig(config, classPropertyName, Converter.class, delegatingLoader.converters());
break;
case PLUGINS:
// Attempt to load with the plugin class loader, which uses the current classloader as a fallback
String converterClassOrAlias = config.getClass(classPropertyName).getName();
try {
klass = pluginClass(delegatingLoader, converterClassOrAlias, Converter.class);
} catch (ClassNotFoundException e) {
throw new ConnectException(
"Failed to find any class that implements Converter and which name matches "
+ converterClassOrAlias + ", available converters are: "
+ pluginNames(delegatingLoader.converters())
);
}
break;
}
if (klass == null) {
throw new ConnectException("Unable to initialize the Converter specified in '" + classPropertyName + "'");
}
// Determine whether this is a key or value converter based upon the supplied property name ...
final boolean isKeyConverter = WorkerConfig.KEY_CONVERTER_CLASS_CONFIG.equals(classPropertyName);
// Configure the Converter using only the old configuration mechanism ...
String configPrefix = classPropertyName + ".";
Map<String, Object> converterConfig = config.originalsWithPrefix(configPrefix);
log.debug("Configuring the {} converter with configuration keys:{}{}",
isKeyConverter ? "key" : "value", System.lineSeparator(), converterConfig.keySet());
Converter plugin;
ClassLoader savedLoader = compareAndSwapLoaders(klass.getClassLoader());
try {
plugin = newPlugin(klass);
plugin.configure(converterConfig, isKeyConverter);
} finally {
compareAndSwapLoaders(savedLoader);
}
return plugin;
}
/**
* Load an internal converter, used by the worker for (de)serializing data in internal topics.
*
* @param isKey whether the converter is a key converter
* @param className the class name of the converter
* @param converterConfig the properties to configure the converter with
* @return the instantiated and configured {@link Converter}; never null
* @throws ConnectException if the {@link Converter} implementation class could not be found
*/
public Converter newInternalConverter(boolean isKey, String className, Map<String, String> converterConfig) {
Class<? extends Converter> klass;
try {
klass = pluginClass(delegatingLoader, className, Converter.class);
} catch (ClassNotFoundException e) {
throw new ConnectException("Failed to load internal converter class " + className);
}
Converter plugin;
ClassLoader savedLoader = compareAndSwapLoaders(klass.getClassLoader());
try {
plugin = newPlugin(klass);
plugin.configure(converterConfig, isKey);
} finally {
compareAndSwapLoaders(savedLoader);
}
return plugin;
}
/**
* If the given configuration defines a {@link HeaderConverter} using the named configuration property, return a new configured
* instance.
*
* @param config the configuration containing the {@link Converter}'s configuration; may not be null
* @param classPropertyName the name of the property that contains the name of the {@link Converter} class; may not be null
* @param classLoaderUsage which classloader should be used
* @return the instantiated and configured {@link HeaderConverter}; null if the configuration did not define the specified property
* @throws ConnectException if the {@link HeaderConverter} implementation class could not be found
*/
public HeaderConverter newHeaderConverter(AbstractConfig config, String classPropertyName, ClassLoaderUsage classLoaderUsage) {
Class<? extends HeaderConverter> klass = null;
switch (classLoaderUsage) {
case CURRENT_CLASSLOADER:
if (!config.originals().containsKey(classPropertyName)) {
// This connector configuration does not define the header converter via the specified property name
return null;
}
// Attempt to load first with the current classloader, and plugins as a fallback.
// Note: we can't use config.getConfiguredInstance because we have to remove the property prefixes
// before calling config(...)
klass = pluginClassFromConfig(config, classPropertyName, HeaderConverter.class, delegatingLoader.headerConverters());
break;
case PLUGINS:
// Attempt to load with the plugin class loader, which uses the current classloader as a fallback.
// Note that there will always be at least a default header converter for the worker
String converterClassOrAlias = config.getClass(classPropertyName).getName();
try {
klass = pluginClass(
delegatingLoader,
converterClassOrAlias,
HeaderConverter.class
);
} catch (ClassNotFoundException e) {
throw new ConnectException(
"Failed to find any class that implements HeaderConverter and which name matches "
+ converterClassOrAlias
+ ", available header converters are: "
+ pluginNames(delegatingLoader.headerConverters())
);
}
}
if (klass == null) {
throw new ConnectException("Unable to initialize the HeaderConverter specified in '" + classPropertyName + "'");
}
String configPrefix = classPropertyName + ".";
Map<String, Object> converterConfig = config.originalsWithPrefix(configPrefix);
converterConfig.put(ConverterConfig.TYPE_CONFIG, ConverterType.HEADER.getName());
log.debug("Configuring the header converter with configuration keys:{}{}", System.lineSeparator(), converterConfig.keySet());
HeaderConverter plugin;
ClassLoader savedLoader = compareAndSwapLoaders(klass.getClassLoader());
try {
plugin = newPlugin(klass);
plugin.configure(converterConfig);
} finally {
compareAndSwapLoaders(savedLoader);
}
return plugin;
}
public ConfigProvider newConfigProvider(AbstractConfig config, String providerPrefix, ClassLoaderUsage classLoaderUsage) {
String classPropertyName = providerPrefix + ".class";
Map<String, String> originalConfig = config.originalsStrings();
if (!originalConfig.containsKey(classPropertyName)) {
// This configuration does not define the config provider via the specified property name
return null;
}
Class<? extends ConfigProvider> klass = null;
switch (classLoaderUsage) {
case CURRENT_CLASSLOADER:
// Attempt to load first with the current classloader, and plugins as a fallback.
klass = pluginClassFromConfig(config, classPropertyName, ConfigProvider.class, delegatingLoader.configProviders());
break;
case PLUGINS:
// Attempt to load with the plugin class loader, which uses the current classloader as a fallback
String configProviderClassOrAlias = originalConfig.get(classPropertyName);
try {
klass = pluginClass(delegatingLoader, configProviderClassOrAlias, ConfigProvider.class);
} catch (ClassNotFoundException e) {
throw new ConnectException(
"Failed to find any class that implements ConfigProvider and which name matches "
+ configProviderClassOrAlias + ", available ConfigProviders are: "
+ pluginNames(delegatingLoader.configProviders())
);
}
break;
}
if (klass == null) {
throw new ConnectException("Unable to initialize the ConfigProvider specified in '" + classPropertyName + "'");
}
// Configure the ConfigProvider
String configPrefix = providerPrefix + ".param.";
Map<String, Object> configProviderConfig = config.originalsWithPrefix(configPrefix);
ConfigProvider plugin;
ClassLoader savedLoader = compareAndSwapLoaders(klass.getClassLoader());
try {
plugin = newPlugin(klass);
plugin.configure(configProviderConfig);
} finally {
compareAndSwapLoaders(savedLoader);
}
return plugin;
}
/**
* If the given class names are available in the classloader, return a list of new configured
* instances. If the instances implement {@link Configurable}, they are configured with provided {@param config}
*
* @param klassNames the list of class names of plugins that needs to instantiated and configured
* @param config the configuration containing the {@link org.apache.kafka.connect.runtime.Worker}'s configuration; may not be {@code null}
* @param pluginKlass the type of the plugin class that is being instantiated
* @return the instantiated and configured list of plugins of type <T>; empty list if the {@param klassNames} is {@code null} or empty
* @throws ConnectException if the implementation class could not be found
*/
public <T> List<T> newPlugins(List<String> klassNames, AbstractConfig config, Class<T> pluginKlass) {
List<T> plugins = new ArrayList<>();
if (klassNames != null) {
for (String klassName : klassNames) {
plugins.add(newPlugin(klassName, config, pluginKlass));
}
}
return plugins;
}
public <T> T newPlugin(String klassName, AbstractConfig config, Class<T> pluginKlass) {
T plugin;
Class<? extends T> klass;
try {
klass = pluginClass(delegatingLoader, klassName, pluginKlass);
} catch (ClassNotFoundException e) {
String msg = String.format("Failed to find any class that implements %s and which "
+ "name matches %s", pluginKlass, klassName);
throw new ConnectException(msg);
}
ClassLoader savedLoader = compareAndSwapLoaders(klass.getClassLoader());
try {
plugin = newPlugin(klass);
if (plugin instanceof Versioned) {
Versioned versionedPlugin = (Versioned) plugin;
if (Utils.isBlank(versionedPlugin.version())) {
throw new ConnectException("Version not defined for '" + klassName + "'");
}
}
if (plugin instanceof Configurable) {
((Configurable) plugin).configure(config.originals());
}
} finally {
compareAndSwapLoaders(savedLoader);
}
return plugin;
}
}
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