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Quokka

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Friendly Boilerplate Engine

Introduction

Quokka is a boilerplate engine. It allows you to quickly use boilerplate templates and avoid copy-pasting chunks of code and snippets when you start a new project. You can create templates for literally anything you want!

Example Usages

  • Generating your CI/CD configuration file
  • Generating skeleton applications with your own best practices
  • More

Features

  • No external dependencies Quokka is written in Go and thus is compiled to a static binary. Download or build it and you're good to go.
  • Local or distant templates Quokka supports both git repositories and local files.
  • Sweet output and prompts Thanks to the wonderful survey library, the prompts are unified, can display an help text and support validation.
  • Clean configuration files Quokka uses YAML for its configuration file formats, making them clean and easy to read.
  • Powerful templating system Quokka uses Go's template system to render the boilerplate.
  • Configuration override Need a different behavior or additional variables in a specific directory? Just add another .quokka.yml file in there. You can even overwrite variables.
  • Conditional prompts (sub-variables) Each variable can have its own subset of variables which will only be prompted to the user if the parent variable is filled or set to true.
  • Customizable templates Quokka enables fine-grained control over what needs to be done when rendering the template. Just copy the file, ignore it, add conditionals based on what the user answered, change the template delimiters…

Installation

Download

You can grab the latest release from the release page.

Build from source

$ go get -u github.com/depado/quokka
$ cd $GOPATH/src/github.com/depado/quokka
$ make

Or directly install:

$ go get -u github.com/depado/quokka
$ cd $GOPATH/src/github.com/depado/quokka
$ make install

Usage

Quokka has two ways of retrieving the templates. It supports git or using a local directory.

Quokka (qk) is a template engine that enables to render local or distant
templates/boilerplates in a user friendly way. When given a URL/Git repository
or a path to a local Quokka template, quokka will ask for the required values
in an interactive way except if an inpute file is given to the CLI.

Usage:
  qk [template] [output] <options> [flags]
  qk [command]

Available Commands:
  help        Help about any command
  new         Create a new quokka template
  version     Show build and version

Flags:
      --debug           Enable or disable debug mode
      --git.depth int   depth of git clone in case of git provider (default 1)
  -h, --help            help for qk
  -i, --input string    specify an input values file to automate template rendering
  -k, --keep            do not delete the template when operation is complete
  -o, --output string   specify the directory where the template should be downloaded or cloned
  -p, --path string     specify if the template is actually stored in a sub-directory of the downloaded file
  -e, --set strings     specify values on the command line
  -y, --yes             Automatically accept

Use "qk [command] --help" for more information about a command.

Keeping the template

When cloning a template, Quokka will create a temporary directory and delete it once the operation completes. If you want to keep the template (to play with it, or simply to keep a copy), make sure you pass the -k/--keep option. This option pairs well with the -o/--output option which defines where the template should be downloaded/cloned.

Input file

The rendering of a Quokka template can be automated if the template was designed with this in mind and if an input file is provided on the command line.

Since there is no clear way for specifying overriding values (for example a variable that applies to a single file and overrides an already existing variable in the root config), the input values will also fill the overriding variables.

The format of the input file is also yaml. The following example demonstrates how an input file could be used:

.quokka.yml

name: "Quokka Template"
description: "New Quokka Template"
version: "0.1.0"
variables:
  slack:
    confirm: true
    prompt: "Add Slack integration?"
    variables:
      channel:
        required: true
      webhook:
        required: true

input.yml

slack: true
slack_channel: "#mychan"
slack_webhook: "complexurl

If this input file is given to Quokka, it won't prompt for these three variables, thus requiring no input from the user to render the template.

Set

Additionally, you can provide Quokka with the -e/--set flag (multiple time if you wish). This works the same way as the input file but has a higher priority, meaning that if you pass both an input file and a -e flag that defines a variable, the one passed on the command line will have a higher priority.

The --set flags work by providing it with a key=value style kind of string. If we take the example above using the input file, we can effectively replace the slack_channel variable by doing so:

$ qk template/ output -i input.yml --set "slack_channel=#anotherchan"
$ # Or
$ qk template/ output -i input.yml -e "slack_channel=#anotherchan"

Examples

$ # Clone the repository and execute the template that is located in _example/license
$ qk [email protected]:Depado/quokka.git output --path _example/license
$ # Clone the template in a specific directory, render it in a specific directory and keep the template
$ qk [email protected]:Depado/quokka.git myamazingproject --path _example/cleanarch --keep --output "template"
$ # Reuse the downloaded template
$ qk template/ myotherproject
$ # Pass an input file to Quokka
$ qk template/ output -i in.yml

Template Creation

New command

If quokka is installed, simply run quokka new <path>. This will ask for basic information such as the template name, description and version with some sane defaults (version number for example is set to 0.1.0 by default). You can also pass these values as flags on the command line.

This command will check if the output directory and a .quokka.yml file already exist. This command is in charge of creating a new directory and creating the initial .quokka.yml file with those basic information, helping you getting started with Quokka template development.

Command Line Help
$ qk new --help
Create a new quokka template

Usage:
  qk new [output] <options> [flags]

Flags:
  -d, --description string   description of the new template
  -h, --help                 help for new
  -n, --name string          name of the new template
  -v, --version string       version of the new template

Global Flags:
      --debug   Enable or disable debug mode
  -y, --yes     Automatically accept

The root .quokka.yml file

To configure your template, place a .quokka.yml at the root of your template. This is called the root configuration, and should contain some information about your template such as its name, its version and a description.

It can also contain overrides for delimiters in the templates (defaults being the go-style {{ .var }}) and variables.

name: "Example Quokka Template"
version: "0.1.0"
description: "An example template to show how quokka works"

Variable declaration

You can add a variables section to your root configuration (or to any .quokka.yml file, or directly inline in your template files, see below) to define the variables you want your user to fill in. There are three types of input you can use:

Simple Input

If you just specify the name of your variable, it will result in a simple input.

variables:
  name:

Selection

variables:
  license:
    values: ["MIT", "Apache License 2.0", "BSD 3", "FreeBSD", "GPL", "LGPL", "WTFPL", "None"]

This will result in a selection input where the user can choose one of the provided choices.

Boolean/Confirmation

variables:
  test:
    confirm: true

If you're using the confirm keyword, it will generate a simple yes/no input. The value you give that confirm key becomes the default value.

Other options and help

You can also help your users by changing the prompt, adding a help text or providing a default value:

variables:
  license:
    values: ["MIT", "Apache License 2.0", "BSD 3", "FreeBSD", "GPL", "LGPL", "WTFPL", "None"]
    prompt: Which license do you want for your project?"
    help: "License file that will be added to your project"
    default: "MIT"
  name:
    default: amazingproject
    prompt: "What's the name of your project?"
    help: "Used to render the README file and various configuration files"

Validation

You can mark any variable as required using the required keyword:

variables:
  name:
    default: amazingproject
    prompt: "What's the name of your project?"
    help: "Used to render the README file and various configuration files"
    required: true

This will prevent the user from rendering your template with missing variables. Note that if you specified a default value for an input, it becomes impossible to not fill in that value. So the validator becomes obsolete.

Sub Variables

It's not uncommon to ask for additional information when the user answered yes or filled in a variable. Thus, each variable can have its own variables:

variables:
  slack:
    confirm: true
    prompt: "Add Slack integration?"
    variables:
      channel:
        required: true
        prompt: "In which Slack channel should the result be posted?"
      webhook:
        required: true
        help: "See https://api.slack.com/incoming-webhooks for more information"
        prompt: "Provide the Slack webhook URL:"

In the example above we ask the user if he wants a Slack integration. If he answers yes to that, then we'll ask him about the Slack channel and the webhook URL. Otherwise we won't bother him with these details since they won't be used in our template rendering.

The sub variables can be accessed in your templates with the form .parent_sub. In this case, .slack_channel and .slack_webhook.

Standard .quokka.yml files

If you place a .quokka.yml file in a sub-directory of your template, this file will apply recursively to all the elements inside that directory and its own sub-directories, meaning that you can override some variables, add new ones, modify the delimiters, or completely ignore an entire directory.

For example you can completely ignore a directory:

└──── change
    ├── override.go
    └── .quokka.yml
copy: true

In this case, the file override.go won't be rendered (but will simply be copied to the output directory). This would apply for every sub-directory, except if a directory contains a .quokka.yml telling otherwise, or a file with an inline configuration. The ignore option can also be used to completely ignore a file or a directory.

ignore: true

Per-file configuration

You can also configure individual files by adding a front matter at the top of the file (that will obviously be removed when rendered).

Let's say I have a file that I don't want to render but simply copy to the output directory:

---
copy: true
---
# This shouldn't be rendered at all !

You can even add per-file variables, or modify the delimiters. In fact, it's like an inline .quokka.yml that applies to a single file.

Supported instructions are as follows:

  • if: condition: Conditional rendering using an expr expression that must return a boolean value
  • copy: true: Do not attempt to render the file and simply copy it to its destination
  • delimiters: ["[[", "]]"]: Change the delimiters used for template rendering. This can be useful for files that already are templates or use extensively the {} chars
  • rename: newname: Rename the file to this new name once rendered
  • ignore: true: Completely ignore the file (no render, no copy)

Conditional Rendering/Copy

You may want some files to not be copied or rendered according to what the user answers to your prompt. You can use the if key (in a .quokka.yml or inline in a file), with the name of one of your variables. For example if you have a variable defined like this in your root config:

variables:
  drone:
    prompt: "Do you want to add a Drone config file?"
    confirm: true

You can then add this at the top of the file:

---
if: drone
---
workspace:
  base: /go
...

This file will be rendered if, and only if, the user answered yes to that question. Note that if and copy can work together if you just want to copy the file and not render it.

ToDo

  • Ignore file list in .quokka.yml
    • Use case: Add a README.md to document the template along with README.md.tmpl with a rename directive. This would avoids the front-matter in the template documentation.