api-cli/bin/cmd.generate.js

const path = require('path');
const fs = require('fs');
const linter = require('./linter');
const prompt = require('./prompt');

function defaultTemplatePath() {
    return path.join(__dirname, '..', 'templates', 'default.json');
}

function defaultOutputPath(name) {
    return path.join(process.cwd(), `${name}.json`)
}

function doInteractiveGeneration(args) {
    prompt.start([
        { question: 'Service name', name: 'name', validator: linter.regex.NAME_REGEX, error: "Name must only contain lowercase letters, numbers or '-_'!" },
        { question: 'Service description', name: 'description', validator: linter.regex.DESCRIPTION_REGEX, error: "Description must be a descriptive sentence starting with a uppercase letter and ending with a '.'!" },
        { question: 'Template', name: 'template', default: defaultTemplatePath},
        { question: 'Output', name: 'output', default: results => defaultOutputPath(results.name) }
    ], results => {
        generateTemplate(results);
    });

}

function doSilentGeneration(args) {
    let config = {};
    config.template = args.template || defaultTemplatePath();
    config.name = args.name;
    config.description = args.description;
    config.output = args.output || defaultOutputPath(args.name) 
 
    generateTemplate(config);
}

function generateTemplate(config) {
    console.log(`Generate Service Spec for service '${config.name}' to ${config.output}`)
    let template = require(config.template);

    template.name = config.name
    template.description = config.description

    let messages = linter.lint(template);
    if(messages.length) {
        console.error("Failed to generate service spec:");
        messages.forEach(message => console.log(`\t${message}`));
        process.exit(-1)
    }

    let output = JSON.stringify(template, null, '\t');
    fs.writeFileSync(config.output, output);
}


module.exports = function(args) {
    if(args.silent) {
        return doSilentGeneration(args);
    }
    return doInteractiveGeneration(args);

}