本文主要是介绍flink源码分析 - 命令行参数解析-CommandLineParser，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
flink版本: flink-1.11.2
调用位置:
org.apache.flink.runtime.entrypoint.StandaloneSessionClusterEntrypoint#main
代码位置:
flink核心命令行解析器:
org.apache.flink.runtime.entrypoint.parser.CommandLineParser
/** 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.flink.runtime.entrypoint.parser;import org.apache.flink.runtime.entrypoint.FlinkParseException;import org.apache.commons.cli.CommandLine;
import org.apache.commons.cli.DefaultParser;
import org.apache.commons.cli.HelpFormatter;
import org.apache.commons.cli.Options;
import org.apache.commons.cli.ParseException;import javax.annotation.Nonnull;/*** Command line parser which produces a result from the given* command line arguments.*/
public class CommandLineParser<T> {@Nonnullprivate final ParserResultFactory<T> parserResultFactory;public CommandLineParser(@Nonnull ParserResultFactory<T> parserResultFactory) {// TODO_MA 注释： parserResultFactory = EntrypointClusterConfigurationParserFactorythis.parserResultFactory = parserResultFactory;}public T parse(@Nonnull String[] args) throws FlinkParseException {final DefaultParser parser = new DefaultParser();final Options options = parserResultFactory.getOptions();final CommandLine commandLine;try {/************************************************** TODO_MA 马中华 https://blog.csdn.net/zhongqi2513* 注释： 解析参数*/commandLine = parser.parse(options, args, true);} catch (ParseException e) {throw new FlinkParseException("Failed to parse the command line arguments.", e);}// TODO_MA 注释： 创建 EntrypointClusterConfiguration 返回return parserResultFactory.createResult(commandLine);}public void printHelp(@Nonnull String cmdLineSyntax) {final HelpFormatter helpFormatter = new HelpFormatter();helpFormatter.setLeftPadding(5);helpFormatter.setWidth(80);helpFormatter.printHelp(cmdLineSyntax, parserResultFactory.getOptions(), true);}
}
其中核心方法是构造方法及parse方法。
构造方法主要用于从外界获取parserResultFactory变量，用于后期解析；
parse(@Nonnull String[] args) 方法用于解析参数。 其中args即为从外部命令行传入的参数。
解析过程中用到的核心对象是
final DefaultParser parser = new DefaultParser();
该对象来源于 Apache Common Cli包，具体用法参考（内部包含官方文档地址）:
使用Apache commons-cli包进行命令行参数解析的示例代码-CSDN博客
核心解析步骤是:
commandLine = parser.parse(options, args, true); 以及
return parserResultFactory.createResult(commandLine);。
其中parser对象进行参数解析。 parserResultFactory主要为parser对象提供需要解析的命令行选项options，及通过 parserResultFactory.createResult(commandLine) 从parser的解析结果commandLine中拿到命令行选项对应值，并构造出相应结果。
ParserResultFactory的接口定义:
/** 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.flink.runtime.entrypoint.parser;import org.apache.flink.runtime.entrypoint.FlinkParseException;import org.apache.commons.cli.CommandLine;
import org.apache.commons.cli.Options;import javax.annotation.Nonnull;/*** Parser result factory used by the {@link CommandLineParser}.** @param <T> type of the parsed result*/
public interface ParserResultFactory<T> {/*** Returns all relevant {@link Options} for parsing the command line* arguments.** @return Options to use for the parsing*/Options getOptions();/*** Create the result of the command line argument parsing.** @param commandLine to extract the options from* @return Result of the parsing* @throws FlinkParseException Thrown on failures while parsing command line arguments*/T createResult(@Nonnull CommandLine commandLine) throws FlinkParseException;
}
其下具体实现类如图所示:
截取两个具体实现供参考:
ClusterConfigurationParserFactory:
/** 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.flink.runtime.entrypoint;import org.apache.flink.runtime.entrypoint.parser.ParserResultFactory;import org.apache.commons.cli.CommandLine;
import org.apache.commons.cli.Options;import javax.annotation.Nonnull;import java.util.Properties;import static org.apache.flink.runtime.entrypoint.parser.CommandLineOptions.CONFIG_DIR_OPTION;
import static org.apache.flink.runtime.entrypoint.parser.CommandLineOptions.DYNAMIC_PROPERTY_OPTION;/*** Parser factory which generates a {@link ClusterConfiguration} from the given* list of command line arguments.*/
public class ClusterConfigurationParserFactory implements ParserResultFactory<ClusterConfiguration> {public static Options options() {final Options options = new Options();options.addOption(CONFIG_DIR_OPTION);options.addOption(DYNAMIC_PROPERTY_OPTION);return options;}@Overridepublic Options getOptions() {return options();}@Overridepublic ClusterConfiguration createResult(@Nonnull CommandLine commandLine) {final String configDir = commandLine.getOptionValue(CONFIG_DIR_OPTION.getOpt());final Properties dynamicProperties = commandLine.getOptionProperties(DYNAMIC_PROPERTY_OPTION.getOpt());return new ClusterConfiguration(configDir, dynamicProperties, commandLine.getArgs());}
}
EntrypointClusterConfigurationParserFactory：
/** 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.flink.runtime.entrypoint;import org.apache.flink.runtime.entrypoint.parser.ParserResultFactory;import org.apache.commons.cli.CommandLine;
import org.apache.commons.cli.Options;import javax.annotation.Nonnull;import java.util.Properties;import static org.apache.flink.runtime.entrypoint.parser.CommandLineOptions.CONFIG_DIR_OPTION;
import static org.apache.flink.runtime.entrypoint.parser.CommandLineOptions.DYNAMIC_PROPERTY_OPTION;
import static org.apache.flink.runtime.entrypoint.parser.CommandLineOptions.EXECUTION_MODE_OPTION;
import static org.apache.flink.runtime.entrypoint.parser.CommandLineOptions.HOST_OPTION;
import static org.apache.flink.runtime.entrypoint.parser.CommandLineOptions.REST_PORT_OPTION;/*** Parser factory for {@link EntrypointClusterConfiguration}.*/
public class EntrypointClusterConfigurationParserFactory implements ParserResultFactory<EntrypointClusterConfiguration> {@Overridepublic Options getOptions() {final Options options = new Options();options.addOption(CONFIG_DIR_OPTION);options.addOption(REST_PORT_OPTION);options.addOption(DYNAMIC_PROPERTY_OPTION);options.addOption(HOST_OPTION);options.addOption(EXECUTION_MODE_OPTION);return options;}@Overridepublic EntrypointClusterConfiguration createResult(@Nonnull CommandLine commandLine) {// TODO_MA 注释： 解析 --configDir -cfinal String configDir = commandLine.getOptionValue(CONFIG_DIR_OPTION.getOpt());// TODO_MA 注释： 解析程序的 -Dkey-value参数final Properties dynamicProperties = commandLine.getOptionProperties(DYNAMIC_PROPERTY_OPTION.getOpt());// TODO_MA 注释： 解析 --webui-port -rfinal String restPortStr = commandLine.getOptionValue(REST_PORT_OPTION.getOpt(), "-1");final int restPort = Integer.parseInt(restPortStr);// TODO_MA 注释： 解析 --host -hfinal String hostname = commandLine.getOptionValue(HOST_OPTION.getOpt());/************************************************** TODO_MA 马中华 https://blog.csdn.net/zhongqi2513* 注释： 返回一个 EntrypointClusterConfiguration 对象*/return new EntrypointClusterConfiguration(configDir,dynamicProperties,commandLine.getArgs(),hostname,restPort);}
}
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