Java tutorial
/******************************************************************************* * Copyright (c) 2012-2017 Codenvy, S.A. * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/epl-v10.html * * Contributors: * Codenvy, S.A. - initial API and implementation *******************************************************************************/ package org.eclipse.che.plugin.docker.client; import org.eclipse.che.commons.lang.Pair; import com.google.common.io.CharSource; import com.google.common.io.CharStreams; import com.google.common.io.Files; import com.google.common.io.Resources; import java.io.File; import java.io.IOException; import java.io.Reader; import java.net.URL; import java.nio.charset.Charset; /** * @author andrew00x */ public class DockerfileParser { /** Parse content of Dockerfile from the specified File. */ public static Dockerfile parse(File file) throws DockerFileException { try { return parse(CharStreams.readLines(Files.newReader(file, Charset.defaultCharset()))); } catch (IOException e) { throw new DockerFileException("Error happened parsing the Docker file." + e.getMessage(), e); } } /** Parse content of Dockerfile from the specified URL. */ public static Dockerfile parse(final URL file) throws DockerFileException { try { return parse( CharStreams.readLines(Resources.asCharSource(file, Charset.defaultCharset()).openStream())); } catch (IOException e) { throw new DockerFileException("Error happened parsing the Docker file:" + e.getMessage(), e); } } /** Parse content of Dockerfile from the specified Reader. */ public static Dockerfile parse(Reader reader) throws DockerFileException { try { return parse(CharStreams.readLines(reader)); } catch (IOException e) { throw new DockerFileException("Error happened parsing the Docker file:" + e.getMessage(), e); } } /** Parse content of Dockerfile that is represented by String value. */ public static Dockerfile parse(String contentOfDockerFile) throws DockerFileException { try { return parse(CharStreams.readLines(CharSource.wrap(contentOfDockerFile).openStream())); } catch (IOException e) { throw new DockerFileException("Error happened parsing the Docker file:" + e.getMessage(), e); } } private static Dockerfile parse(Iterable<String> lines) throws DockerFileException { final Dockerfile dockerfile = new Dockerfile(); DockerImage current = null; for (String line : lines) { line = line.trim(); dockerfile.getLines().add(line); if (!line.isEmpty()) { Instruction instruction; if ((instruction = getInstruction(line)) == null) { continue; } if (instruction == Instruction.FROM) { if (current != null) { dockerfile.getImages().add(current); } current = new DockerImage(); instruction.setInstructionArgumentsToModel(current, line); } else { if (current == null) { if (instruction != Instruction.COMMENT) { throw new DockerFileException( "Error happened parsing the Docker file: Docker file must start with 'FROM' instruction"); } } else { instruction.setInstructionArgumentsToModel(current, line); } } } } if (current != null) { dockerfile.getImages().add(current); } return dockerfile; } private static Instruction getInstruction(String line) { if (line.startsWith("#")) { return Instruction.COMMENT; } // By convention instruction should be UPPERCASE but it is not required. final String lowercase = line.toLowerCase(); if (lowercase.startsWith("from")) { return Instruction.FROM; } else if (lowercase.startsWith("maintainer")) { return Instruction.MAINTAINER; } else if (lowercase.startsWith("run")) { return Instruction.RUN; } else if (lowercase.startsWith("cmd")) { return Instruction.CMD; } else if (lowercase.startsWith("expose")) { return Instruction.EXPOSE; } else if (lowercase.startsWith("env")) { return Instruction.ENV; } else if (lowercase.startsWith("add")) { return Instruction.ADD; } else if (lowercase.startsWith("entrypoint")) { return Instruction.ENTRYPOINT; } else if (lowercase.startsWith("volume")) { return Instruction.VOLUME; } else if (lowercase.startsWith("user")) { return Instruction.USER; } else if (lowercase.startsWith("workdir")) { return Instruction.WORKDIR; } else if (lowercase.startsWith("onbuild")) { return Instruction.ONBUILD; } return null; } private enum Instruction { FROM { @Override void setInstructionArgumentsToModel(DockerImage model, String line) throws DockerFileException { model.setFrom(getInstructionArguments(line)); } }, MAINTAINER { @Override void setInstructionArgumentsToModel(DockerImage model, String line) throws DockerFileException { model.getMaintainer().add(getInstructionArguments(line)); } }, RUN { @Override void setInstructionArgumentsToModel(DockerImage model, String line) throws DockerFileException { model.getRun().add(getInstructionArguments(line)); } }, CMD { @Override void setInstructionArgumentsToModel(DockerImage model, String line) throws DockerFileException { model.setCmd(getInstructionArguments(line)); } }, EXPOSE { @Override void setInstructionArgumentsToModel(DockerImage model, String line) throws DockerFileException { final String args = getInstructionArguments(line); final int l = args.length(); int i = 0, j = 0; while (j < l) { while (j < l && !Character.isWhitespace(args.charAt(j))) { j++; } model.getExpose().add(args.substring(i, j)); i = j; while (i < l && Character.isWhitespace(args.charAt(i))) { i++; } j = i; } } }, ENV { @Override void setInstructionArgumentsToModel(DockerImage model, String line) throws DockerFileException { final String args = getInstructionArguments(line); final int l = args.length(); int i = 0; while (i < l && !Character.isWhitespace(args.charAt(i))) { i++; } if (i < l) { int j = i; while (j < l && Character.isWhitespace(args.charAt(j))) { j++; } if (j < l) { model.getEnv().put(args.substring(0, i), args.substring(j)); } else { model.getEnv().put(args.substring(0, i), null); } } else { model.getEnv().put(args, null); } } }, ADD { @Override void setInstructionArgumentsToModel(DockerImage model, String line) throws DockerFileException { final String args = getInstructionArguments(line); final int l = args.length(); int i = 0; while (i < l && !Character.isWhitespace(args.charAt(i))) { i++; } if (i < l) { int j = i; while (j < l && Character.isWhitespace(args.charAt(j))) { j++; } if (j < l) { model.getAdd().add(Pair.of(args.substring(0, i), args.substring(j))); } else { // respect this even it's not legal for docker file model.getAdd().add(Pair.of(args.substring(0, i), (String) null)); } } else { // respect this even it's not legal for docker file model.getAdd().add(Pair.of(args, (String) null)); } } }, ENTRYPOINT { @Override void setInstructionArgumentsToModel(DockerImage model, String line) throws DockerFileException { model.setEntrypoint(getInstructionArguments(line)); } }, VOLUME { @Override void setInstructionArgumentsToModel(DockerImage model, String line) throws DockerFileException { String args = getInstructionArguments(line); if (!args.isEmpty()) { final int l = args.length(); if (args.charAt(0) != '[' || args.charAt(l - 1) != ']') { throw new DockerFileException(String.format( "Error happened parsing the Docker file: Invalid argument '%s' for 'VOLUME' instruction", args)); } int i = 1, j = 1, end = l - 1; while (j < end) { while (j < end && args.charAt(j) != ',') { j++; } String volume = args.substring(i, j); if (!volume.isEmpty()) { if ((volume.charAt(0) == '"' && volume.charAt(volume.length() - 1) == '"') || (volume.charAt(0) == '\'' && volume.charAt(volume.length() - 1) == '\'')) { volume = volume.substring(1, volume.length() - 1); } if (!volume.isEmpty()) { model.getVolume().add(volume); } } i = j + 1; while (i < end && Character.isWhitespace(args.charAt(i))) { i++; } j = i; } } } }, USER { @Override void setInstructionArgumentsToModel(DockerImage model, String line) throws DockerFileException { model.setUser(getInstructionArguments(line)); } }, WORKDIR { @Override void setInstructionArgumentsToModel(DockerImage model, String line) throws DockerFileException { model.setWorkdir(getInstructionArguments(line)); } }, COMMENT { @Override void setInstructionArgumentsToModel(DockerImage model, String line) throws DockerFileException { model.getComments().add(getInstructionArguments(line)); } @Override String getInstructionArguments(String line) { return line.substring(1).trim(); } }, ONBUILD { @Override void setInstructionArgumentsToModel(DockerImage model, String line) throws DockerFileException { model.getOnbuild().add(line.substring(name().length()).trim()); } }; abstract void setInstructionArgumentsToModel(DockerImage model, String line) throws DockerFileException; String getInstructionArguments(String line) { return line.substring(name().length()).trim(); } } private DockerfileParser() { } }