Easy Template

Quick and Dirty Jinja templating from CLI with YAML

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This is a work in progress, subject to many changes and new instabilities / brokenness.

Introduction

This project was made because I liked the templating workflow that's present in Ansible, but I found that installing Ansible just for the templating is kind of inconvenient.

So here we have the jinja templating system ingesting YAML, all run via some click CLI commands.
No inventory, group_vars, hostnames, or other Ansible-related considerations necessary.

Getting started

Install easy-template:

python3 -m venv venv
source venv/bin/activate
pip install git+https://github.com/camratchford/easy-template

Create config file:

Ex: example_files/config.yml

external_function_dir: ./path/to/jinja_functions
force_overwrite: True
load_env_vars: True
debug: False

# Parameters from https://jinja.palletsprojects.com/en/3.1.x/api/#high-level-api are passed to the Jinja environment object
jinja_config:
  trim_blocks: False
  newline_sequence: '\n'
  keep_trailing_newline: False
  auto_reload: False
  optimized: True

# Will be applied to every template, but can be over-ridden by var files
global_variables:
  name: Person McPersonface
  email: Person.McPersonface@example.com
  github_profile: https://github.com/pmcpface

Create template file

Ex: example_files/readme_template.md.j2

# {{ title }}

{{ description }}

> {{ disclaimer }}

{% if toc %}
{% for t in toc %}
- [{{ t.label }}]({{ t.link }})
{% endfor %}
{% endif %}

Author: [{{ name }}]({{ github_profile }})

Contact: [{{ email }}](mailto:{{ email }})

Create var file:

Ex: example_files/vars.yml

title: How to make a cheeseburger
description: A simple step by step guide on how to make juicy burgers
disclaimer: I am not a professional. Any injury, disablement, or deaths caused by the burgers you consume are not my fault.
toc:
  - label: Get meat
    link: ./docs/meats.md
  - label: Cook meat
    link: ./docs/cooking.md
  - label: Enjoy
    link: ./docs/enjoy.md

Run

Ex: example_files/example_script.sh

# Config path arg is absolute, var and template args are relative to their respective directories defined in the config file
ezt.exe --force \
  -c "example_files/config.yml" \
  -t "example_files/readme_template.md.j2" \
  -v "title=How do you make a cheeseburger?" \
  --var-file "example_files/vars.yml" \
  -o "example_files/README.md"

This command reads in the config file ~/ezt/config.yml, parses the variables in ~/vars/templatesreadme.yml, loads the variables defined in the -v argument, then processes the template with the loaded variables, outputting the file in the path defined with the -o argument

The command outputs a file README.md to the output directory defined in your config.

Ex: The contents of example_files/README.md

# How do you make a cheeseburger?

A simple step by step guide on how to make juicy burgers

> I am not a professional. Any injury, disablement, or deaths caused by the burgers you consume are not my fault.



- [Get meat](./docs/meats.md)

- [Cook meat](./docs/cooking.md)

- [Enjoy](./docs/enjoy.md)



Author: [Person McPersonface](https://github.com/pmcpface)

Contact: [Person.McPersonface@example.com](mailto:Person.McPersonface@example.com)

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Command-line arguments

Configuration Item	Abrv	Keyword Argument	Config File Key	Default	Required	Description
config_file	-c	--config	N/A	N/A	No	The location of the yaml configuration file.
variables	-v	--variables	variables	[]	No	A 'a_variable=some value' pair representing a variable, Variable arguments
var_file	-V	--var-file	var_file	""	No	The path to a yaml file containing key: value pairs, representing variables
output	-o	--output	output	""	No*	The path where you'll find the output of ezt
template_file	-t	--template-file	N/A	""	No**	The path pointing toward the jinja template that ezt will use to create it's output
tree_dir	-d	--tree-dir	tree_directory	""	No**	Specifies the directory to recursively perform templating on
external_function_dir	-e	--external-function-dir	external_function_dir	""	No	The path pointing toward a folder of python files which contain jinja2 filter/test functions
force_overwrite	-f	--force	force_overwrite	False	No	When true, output will overwrite any file in that path
load_env_vars	--env	--load-environment-vars	load_env_vars	False	No	Will load Environment variables in as jinja variables
jinja_config	N/A	N/A	jinja_config	""	No	Jinja templating engine options
log_config	N/A	N/A	log_config	{}	No	logging.dictConfig
global_variables	N/A	N/A	global_variables	{}	No	Another, more static, way to set variables.***
rich_std_out	N/A	--no-rich-stdout	rich_std_out	True	No	Formats output string with Rich
rich_markdown_stdout	N/A	--markdown	rich_markdown_stdout	False	No	Formats output string with Rich's Markdown module
rich_theme	N/A	--rich-theme	rich_theme	"zenburn"	No	Changes the output theme for Rich to one of the Pygment Styles
export_config	N/A	--export-config	export_config	False	No	When true, the current set of configuration items will be exported to ./export_config.yml

Key	Notes
*	Unless rich_stdout is disabled.
**	You must use either the --tree or --template-file option. Using both or neither will result in an error.
***	Variables declared in this way will be over-ridden by any successive variable declarations. It is advised to use this method to store default values.

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Variables

The variables are applied in the following order, with each instance of a variable being overwritten by any subsequent instances.

1. Global variables (defined in the config file under the key global_variables)
2. Environment variables (If the load_env_vars configuration item is set to True)
3. Variable file (Variables within a yaml file defined in the --var-file argument)
4. Variable arguments (Variables defined using the -v argument)

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External Jinja2 Functions (Filters and Tests)

To use external Jinja2 filter functions, you may the switch --external-function-dir path/to/function/dir or the config file key external_function_dir: some/path/to/function/, to point to a path containing any number of the 2 python modules "filters" and "tests".

Setting the variable --external-function-dir ~\ezt\example_external_functions

# Example directory tree:
~\ezt\example_external_functions\
~\ezt\example_external_functions\filters\
~\ezt\example_external_functions\filters\filters.py
~\ezt\example_external_functions\tests\
~\ezt\example_external_functions\tests\tests.py

Each function contained in either "filters" or "tests" modules will be merged into the set of filters and tests available to the user in jinja template tags It will be helpful to read the official Jinja2 documentation on the subjects

• fiters
• tests

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Logging

Easy-Template has the ability to keep and store logs. This might be useful for debugging templating errors, and other record keeping tasks.

Logging config

Configuration of Python's logging module is done bia the logging.dictConfig method Examples of how to implement this can be found in the official documentation

Simply add the requisite configuration in your ezt config file under the key logging_config:

Ex: ~/example_files/config.yml

# ...
# Your normal config keys above

log_config:
  version: 1
  disable_existing_loggers: True
  formatters:
    verbose:
      fmt: |
        %(process)s -> %(filename)s -> %(levelprefix)s -> %(module)s -> %(funcName)s -> %(lineno)s ->> %(message)s
      use_colors: True
  handlers:
    default:
      class : logging.handlers.RotatingFileHandler
      formatter: verbose
      filename: ez_temp.log
      maxBytes: 1024
      backupCount: 3
  loggers:
    ez_temp:
      handlers: default
      level: DEBUG
      propagate: True

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Compiling

Linux

• Make sure you have the python & python-dev >= 3.8 installed
• Create a virtual environment
• Install the package

cd ./EasyTemplate
python3 -m venv venv
source venv/bin/activate
pip install .

• Compile

cd ./compilation
bash ./compile.sh

• Copy it somewhere in $PATH

cp ./build/ezt /usr/bin/ezt

Windows

• Make sure Python >= 3.8 is installed
• (for some reason) Install pyinstaller to your system Python interpreter's library

pip install pyinstaller

• Run the PowerShell script

cd .\EasyTemplate\compilation\
# It will create the venv and test the program
.\compile.ps1

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Author

Cam Ratchford

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License

CC0 1.0 Universal

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