maven fmpp 插件开发说明

实际上已经有几个 fmpp maven 插件，但是不是很好用，dremio 自己包装了一个，然后fork 了dremio fmpp 插件的代码独立包装了一些
同时发布到github repo 中，方便使用

参考代码

• pom.xml

<?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"><modelVersion>4.0.0</modelVersion> 
<groupId>com.rongfengliang</groupId><artifactId>fmpp-maven-plugin</artifactId><packaging>maven-plugin</packaging><version>1.0</version><properties><maven.compiler.source>8</maven.compiler.source><maven.compiler.target>8</maven.compiler.target><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><commons-io.version>2.11.0</commons-io.version><guava.version>31.1-jre</guava.version><fmpp.version>0.9.16</fmpp.version><freemarker.version>2.3.31</freemarker.version></properties><dependencies><dependency><groupId>com.google.guava</groupId><artifactId>guava</artifactId><version>${guava.version}</version></dependency><dependency><groupId>commons-io</groupId><artifactId>commons-io</artifactId><version>${commons-io.version}</version></dependency><dependency><groupId>org.apache.maven</groupId><artifactId>maven-core</artifactId><version>3.3.9</version><scope>provided</scope><exclusions><exclusion><artifactId>commons-logging</artifactId><groupId>commons-logging</groupId></exclusion></exclusions></dependency><dependency><groupId>org.apache.maven</groupId><artifactId>maven-plugin-api</artifactId><version>3.3.9</version><scope>provided</scope></dependency><dependency><groupId>org.apache.maven.plugin-tools</groupId><artifactId>maven-plugin-annotations</artifactId><version>3.6.4</version><scope>provided</scope></dependency><dependency><groupId>net.sourceforge.fmpp</groupId><artifactId>fmpp</artifactId><version>${fmpp.version}</version></dependency><dependency><groupId>org.freemarker</groupId><artifactId>freemarker</artifactId><version>${freemarker.version}</version></dependency></dependencies><build><plugins><plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-plugin-plugin</artifactId><version>3.6.2</version><configuration><goalPrefix>rongfengliang-fmpp</goalPrefix></configuration><executions><execution><id>default-descriptor</id><goals><goal>descriptor</goal></goals><phase>process-classes</phase></execution><execution><id>help-descriptor</id><goals><goal>helpmojo</goal></goals><phase>process-classes</phase></execution></executions></plugin></plugins></build><distributionManagement><repository><id>github</id><name>fmpp maven plugin</name><url>https://maven.pkg.github.com/rongfengliang/fmpp-maven-plugin</url></repository></distributionManagement></project>• 核心插件代码 

FMPPMojo.java 核心是使用fmpp 的api 进行构建，同时进行配置参数设置，运行的阶段是生成source 

fmpp 包含了配置，模版以及输出目录，当然dremio 还扩展了支持data，实际上基于配置就可以加载数据 

数据加载dremio 配置了自己的MavenDataLoader 
package com.rongfengliang; 
import com.google.common.base.Joiner;import com.google.common.base.Stopwatch;import fmpp.Engine;import fmpp.ProgressListener;import fmpp.progresslisteners.TerseConsoleProgressListener;import fmpp.setting.Settings;import fmpp.util.MiscUtil;import org.apache.commons.io.FileUtils;import org.apache.maven.plugin.AbstractMojo;import org.apache.maven.plugin.MojoExecutionException;import org.apache.maven.plugin.MojoFailureException;import org.apache.maven.plugins.annotations.LifecyclePhase;import org.apache.maven.plugins.annotations.Mojo;import org.apache.maven.plugins.annotations.Parameter;import org.apache.maven.project.MavenProject; 
import java.io.File;import java.io.IOException;import java.nio.file.Files;import java.util.ArrayList;import java.util.List;import java.util.concurrent.TimeUnit; 
import static java.lang.String.format; 
/*** a maven plugin to run the freemarker generation incrementally* (if output has not changed, the files are not touched)*/@Mojo(name = "generate", defaultPhase = LifecyclePhase.GENERATE_SOURCES)public class FMPPMojo extends AbstractMojo { 
/*** Used to add new source directories to the build.**/@Parameter(defaultValue = "${project}", readonly = true, required = true)private MavenProject project; 
/*** Where to find the FreeMarker template files.*/@Parameter(defaultValue = "src/main/resources/fmpp/templates/", required = true)private File templates; 
/*** Where to write the generated files of the output files.*/@Parameter(defaultValue = "${project.build.directory}/generated-sources/fmpp/", required = true)private File output; 
/*** Location of the FreeMarker config file.*/@Parameter(defaultValue = "src/main/resources/fmpp/config.fmpp", required = true)private File config; 
/*** compilation scope to be added to ("compile" or "test")*/@Parameter(defaultValue = "compile", required = true)private String scope; 
@Parameterprivate String data; 
/*** if maven properties are added as data*/@Parameter(defaultValue = "true", required = true)private boolean addMavenDataLoader; 
@Overridepublic void execute() throws MojoExecutionException, MojoFailureException {if (project == null) {throw new MojoExecutionException("This plugin can only be used inside a project.");}String outputPath = output.getAbsolutePath();if ((!output.exists() && !output.mkdirs()) || !output.isDirectory()) {throw new MojoFailureException("can not write to output dir: " + outputPath);}String templatesPath = templates.getAbsolutePath();if (!templates.exists() || !templates.isDirectory()) {throw new MojoFailureException("templates not found in dir: " + outputPath);} 
// add the output directory path to the project source directoriesswitch (scope) {case "compile":project.addCompileSourceRoot(outputPath);break;case "test":project.addTestCompileSourceRoot(outputPath);break;default:throw new MojoFailureException("scope must be compile or test");} 
final Stopwatch sw = Stopwatch.createStarted();try {getLog().info(format("Freemarker generation:\n scope: %s,\n config: %s,\n templates: %s",scope, config.getAbsolutePath(), templatesPath));final File tmp = Files.createTempDirectory("freemarker-tmp").toFile();String tmpPath = tmp.getAbsolutePath();final String tmpPathNormalized = tmpPath.endsWith(File.separator) ? tmpPath : tmpPath + File.separator;Settings settings = new Settings(new File("."));settings.set(Settings.NAME_SOURCE_ROOT, templatesPath);settings.set(Settings.NAME_OUTPUT_ROOT, tmp.getAbsolutePath());settings.load(config);settings.addProgressListener(new TerseConsoleProgressListener());settings.addProgressListener(new ProgressListener() {@Overridepublic void notifyProgressEvent(Engine engine, int event,File src, int pMode,Throwable error, Object param)throws Exception {if (event == EVENT_END_PROCESSING_SESSION) {getLog().info(format("Freemarker generation took %dms", sw.elapsed(TimeUnit.MILLISECONDS)));sw.reset();Report report = moveIfChanged(tmp, tmpPathNormalized);if (!tmp.delete()) {throw new MojoFailureException(format("can not delete %s", tmp));}getLog().info(format("Incremental output update took %dms", sw.elapsed(TimeUnit.MILLISECONDS)));getLog().info(format("new: %d", report.newFiles));getLog().info(format("changed: %d", report.changedFiles));getLog().info(format("unchanged: %d", report.unchangedFiles));}}} );List<String> dataValues = new ArrayList<>();if (addMavenDataLoader) {getLog().info("Adding maven data loader");settings.setEngineAttribute(MavenDataLoader.MAVEN_DATA_ATTRIBUTE, new MavenDataLoader.MavenData(project));dataValues.add(format("maven: %s()", MavenDataLoader.class.getName()));}if (data != null) {dataValues.add(data);}if(!dataValues.isEmpty()) {String dataString = Joiner.on(",").join(dataValues);getLog().info("Setting data loader "+ dataString); 
settings.add(Settings.NAME_DATA, dataString);}settings.execute();} catch (Exception e) {throw new MojoFailureException(MiscUtil.causeMessages(e), e);}} 
private static final class Report {private int changedFiles;private int unchangedFiles;private int newFiles;Report(int changedFiles, int unchangedFiles, int newFiles) {super();this.changedFiles = changedFiles;this.unchangedFiles = unchangedFiles;this.newFiles = newFiles;}public Report() {this(0, 0, 0);}void add(Report other) {changedFiles += other.changedFiles;unchangedFiles += other.unchangedFiles;newFiles += other.newFiles;}public void addChanged() {++ changedFiles;}public void addNew() {++ newFiles;}public void addUnchanged() {++ unchangedFiles;}} 
private Report moveIfChanged(File root, String tmpPath) throws MojoFailureException, IOException {Report report = new Report();for (File file : root.listFiles()) {if (file.isDirectory()) {report.add(moveIfChanged(file, tmpPath));if (!file.delete()) {throw new MojoFailureException(format("can not delete %s", file));}} else {String absPath = file.getAbsolutePath();if (!absPath.startsWith(tmpPath)) {throw new MojoFailureException(format("%s should start with %s", absPath, tmpPath));}String relPath = absPath.substring(tmpPath.length());File outputFile = new File(output, relPath);if (!outputFile.exists()) {report.addNew();} else if (!FileUtils.contentEquals(file, outputFile)) {getLog().info(format("%s has changed", relPath));if (!outputFile.delete()) {throw new MojoFailureException(format("can not delete %s", outputFile));}report.addChanged();} else {report.addUnchanged();}if (!outputFile.exists()) {File parentDir = outputFile.getParentFile();if (parentDir.exists() && !parentDir.isDirectory()) {throw new MojoFailureException(format("can not move %s to %s as %s is not a dir", file, outputFile, parentDir));}if (!parentDir.exists() && !parentDir.mkdirs()) {throw new MojoFailureException(format("can not move %s to %s as dir %s can not be created", file, outputFile, parentDir));}FileUtils.moveFile(file, outputFile);} else {if (!file.delete()) {throw new MojoFailureException(format("can not delete %s", file));}}}}return report;}}

• 构建以及发布
  直接基于了github repo 进行发布，配置好账户token 就可以了

mvn clean package deploy

说明

最近在研究dremio sql 解析部分，使用到了fmpp 工具，为了方便使用，基于dremio 的源码，自己构建了一个

参考资料

​​https://github.com/rongfengliang/fmpp-maven-plugin​​​
​​​https://github.com/dremio/dremio-oss/tree/master/tools/fmpp-maven-plugin​​​
​​​https://fmpp.sourceforge.net/manual.html​​​
​​​https://fmpp.sourceforge.net/writefrontend.html​​