Adds clone cli command

Implements a slightly different version of build-blueprint-commands and build-blueprint-command.

If the cli will have more commands it might be a good idea to make those two files adaptable to different descriptions, usages, etc.

src/cli/cmds/clone.js

@@ -0,0 +1,35 @@
+import buildBlueprintCommands from './clone/build-blueprint-commands';
+
+const usage = `Usage:
+  $0 clone <blueprint> <name>
+  $0 help clone <blueprint>`;
+
+module.exports = {
+  command: 'clone <blueprint> <name>',
+  aliases: ['g', 'gen'],
+  describe: 'Clone a blueprint with a different name',
+  builder: yargs => {
+    yargs
+      .usage(usage)
+      .option('dry-run', {
+        alias: 'd',
+        describe: "List files but don't generate them",
+        type: 'boolean'
+      })
+      .option('verbose', {
+        alias: 'v',
+        describe: 'Verbose output, including file contents',
+        type: 'boolean'
+      })
+      .group(['dry-run', 'verbose', 'help'], 'Generate Options:')
+      .updateStrings({
+        'Commands:': 'Blueprints:',
+        'Options:': 'Blueprint Options:'
+      });
+    return buildBlueprintCommands().reduce(
+      (yargs, command) => yargs.command(command),
+      yargs
+    );
+  },
+  handler: argv => console.error(`Unrecognised blueprint '${argv.blueprint}'`)
+};

src/cli/cmds/clone/build-blueprint-command.js

@@ -0,0 +1,96 @@
+/*
+  Build a yargs command module object from options defined in the blueprint
+  https://github.com/yargs/yargs/blob/master/docs/advanced.md#providing-a-command-module
+
+  Target object structure:
+  {
+    command: 'blueprint <name>',
+    aliases: [],
+    describe: 'Generates a blueprint',
+    builder: yargs => yargs,
+    handler: argv => runner.run()
+  }
+*/
+const buildBlueprintCommand = (blueprint, runner) => {
+  // extract custom command pieces
+  let {
+    aliases = [],
+    options,
+    examples,
+    epilog,
+    epilogue,
+    check,
+    sanitize
+  } = blueprint.command;
+
+  // mandate the command name to guarantee name is passed to generate task
+  let command = `${blueprint.name} <name>`;
+
+  // rc aliases override blueprint configuration
+  aliases = [].concat(blueprint.settings.aliases || aliases);
+
+  // default usage
+  let usage = `Usage:\n  $0 clone ${command}`;
+  aliases.forEach(
+    alias =>
+      (usage += `\n  $0 clones ${command.replace(blueprint.name, alias)}`)
+  );
+
+  // default options from settings
+  if (options && blueprint.settings) {
+    Object.keys(options).forEach(option => {
+      if (blueprint.settings[option]) {
+        options[option].default = blueprint.settings[option];
+      }
+    });
+  }
+
+  // alterate epilogue keys
+  epilogue = epilogue || epilog;
+
+  // builder brings together multiple customizations, whilst keeping the
+  // options easy to parse for prompting in the init command
+  const builder = yargs => {
+    yargs.usage(usage).strict(false); // allow undocumented options through
+
+    if (options) yargs.options(options);
+    if (check) yargs.check(check, false);
+    if (examples) {
+      [].concat(examples).forEach(example => yargs.example(example));
+    }
+    if (epilogue) yargs.epilogue(epilogue);
+
+    return yargs;
+  };
+
+  // handler runs the generate blueprint task
+  const handler = argv => {
+    // merge command line options into rc options
+    let options = { ...blueprint.settings, ...argv };
+
+    // tidy up options before passing them on so that all hooks have access
+    // to the clean version
+    if (sanitize) options = sanitize(options);
+
+    const cliArgs = {
+      entity: {
+        name: argv.name,
+        options,
+        rawArgs: argv
+      },
+      debug: argv.verbose || false,
+      dryRun: argv.dryRun || false
+    };
+    runner.run(blueprint.name, cliArgs);
+  };
+
+  return {
+    command,
+    aliases,
+    describe: `Clones ${blueprint.name}`,
+    builder,
+    handler
+  };
+};
+
+export default buildBlueprintCommand;

src/cli/cmds/clone/build-blueprint-commands.js

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+import _merge from 'lodash/merge';
+import _cloneDeep from 'lodash/cloneDeep';
+
+import getEnvironment from '../../environment';
+import Clone from '../../../sub-commands/clone';
+import buildBlueprintCommand from './build-blueprint-command';
+
+const loadBlueprintSettings = (blueprint, bp) =>
+  (blueprint.settings = _merge(
+    _cloneDeep(bp.common),
+    _cloneDeep(bp[blueprint.name])
+  ));
+
+const buildBlueprintCommands = () => {
+  const environment = getEnvironment();
+  const subCommand = new Clone(environment);
+
+  const { blueprints, settings: { bp = {} } } = environment.settings;
+
+  return blueprints.generators().map(blueprint => {
+    loadBlueprintSettings(blueprint, bp);
+    return buildBlueprintCommand(blueprint, subCommand);
+  });
+};
+
+export default buildBlueprintCommands;