net.oneandone.stool.client.cli.Help Maven / Gradle / Ivy

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Stool client to control the server from the command line and build images (on the server, without local docker).
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/*
 * Copyright 1&1 Internet AG, https://github.com/1and1/
 *
 * Licensed 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 net.oneandone.stool.client.cli;

import com.googlecode.lanterna.terminal.ansi.UnixTerminal;
import net.oneandone.stool.client.Globals;
import net.oneandone.sushi.fs.World;
import net.oneandone.sushi.fs.file.FileNode;

import java.io.IOException;
import java.io.InputStream;
import java.util.zip.GZIPInputStream;

public class Help {
    private final World world;
    private final String command;

    public Help(Globals globals, String command) {
        this.world = globals.getWorld();
        this.command = command;
    }

    public void run() throws Exception {
        ProcessBuilder builder;
        Process process;
        FileNode tmp;

        builder = new ProcessBuilder();
        builder.directory(null /* use current directory */);
        builder.command("less");
        tmp = format();
        try {
            builder.redirectInput(tmp.toPath().toFile());
            builder.redirectOutput(ProcessBuilder.Redirect.INHERIT);
            builder.redirectError(ProcessBuilder.Redirect.INHERIT);
            process = builder.start();
            process.waitFor();
        } finally {
            tmp.deleteFile();
        }
        System.out.println();
    }

    private FileNode format() throws Exception {
        ProcessBuilder builder;
        Process process;
        String name;
        FileNode tmp;

        builder = new ProcessBuilder();
        builder.directory(null /* use current directory */);
        builder.command("groff", "-man", "-Tascii",
                /* explicitly configure column width because groff does not see the terminal (since I have to pipe the input stream */
                "-rLL=" + getColumns() + "n");
        tmp = world.getTemp().createTempFile();
        builder.redirectInput(ProcessBuilder.Redirect.PIPE);
        builder.redirectOutput(tmp.toPath().toFile());
        builder.redirectError(ProcessBuilder.Redirect.INHERIT);
        process = builder.start();
        name = command == null ? "sc" : "sc-" + command;
        try (InputStream src = world.resource("templates/man/man1/" + name + ".1.gz").newInputStream()) {
            try (GZIPInputStream unzip = new GZIPInputStream(src)) {
                world.getBuffer().copy(unzip, process.getOutputStream());
            }
        }
        process.getOutputStream().close();
        process.waitFor();
        return tmp;
    }

    // See https://stackoverflow.com/questions/1286461/can-i-find-the-console-width-with-java
    // Jline works as well, but the jar is larger
    // I also tried writing the ansi sequences, but I was unable to capture the reported cursor position ...
    private int getColumns() {
        try {
            return new UnixTerminal().findTerminalSize().getColumns();
        } catch (IOException e) {
            throw new IllegalStateException(e);
        }
    }
}