Temply

Render jinja2 templates on the command line without python runtime.

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📦 Prerequisites

• Python 3.11+ for development.
• Poetry for build system.
• Poe for task runner.
• Up for dependency updates.
• Podman for container packaging.
• pre-commit for git management.

✨ Features

• Render jinja2 template using command line without python environment.
• Standalone executable with jinja2 templating engine.
• Support inclusion template rendering.
• Command line fully compatible with envtpl.
• Support loading from environment variables.

🎯 Motivation

• We needed a way to generate files using data sources in a container environment.
• The solution should be standalone and delivered as a binary.

🔨 Workflow

Setup

The following steps will ensure your project is cloned properly.

1. Clone repository:

   git clone https://github.com/amannocci/temply
   cd temply

2. Use version defined in .python-version:

   pyenv install

3. Install dependencies and setup environment:

   poetry install
   poetry shell
   poetry poe env:configure

Lint

• To lint you have to use the workflow.

poetry poe lint

Format

• To format you have to use the workflow.

poetry poe fmt

• It will format the project code using black and isort.

Build

• To build you have to use the workflow.

poetry poe build

• It will compile project code with the current environment.

Test

• To test temply you have to use the workflow.
• Tests are based on pytest.

poetry poe test

📖 Usage

How it works

• We use PyInstaller to create a standalone executable.
• This means you don't need python runtime to run it.
• This means also that we have a dependency with glibc version.
• To be compatible with a wide range of linux, we build the project using an old glibc version.
• If the project don't run, you will have to re-build it using your distribution.
• When the project start, it will look at the template, found the directory of the template and then configure jinja2 the filesystem.
• It will then attempt to render the template and create a file or display on stdout.
• You can use any jinja2 syntax.

How to render a simple configuration

• Before anything, note that you can render any file with any extension because jinja2 is based on text templating.
• Create a file where you want /path/to/template.yml.tpl with the following content.

variable = '{{ variable }}'
another_one = '{{ another_one }}'
default_var = '{{ default_missing_var | default("default") }}'

• Then launch the command below to render.

variable=foo another_one=bar temply -o /path/to/template.yml /path/to/template.yml.tpl

• It will create a file /path/to/template.yml with the following content.

variable = 'foo'
another_one = 'bar'
default_var = 'default'

How to render a configuration from stdin

• Launch the command below to render.

echo 'Hello {{ name }} !' | name=world temply -o /path/to/template.txt

• It will create a file /path/to/template.txt with the following content.

Hello world !

How to render an advanced configuration

• Create a file where you want /path/to/template.yml.tpl with the following content.

{% include "include.yml.tpl" %}

• And another one at /path/to/include.yml.tpl with the following content.

foobar="Hello world !"

• Then launch the command below to render.

temply -o /path/to/template.yml /path/to/template.yml.tpl

• It will create a file /path/to/template.yml with the following content.

foobar="Hello world !"

How to render a configuration with missing environment variables.

• Create a file where you want /path/to/template.yml.tpl with the following content.

missing_var = '{{ missing_var }}'

• Then launch the command below to render.

temply --allow-missing -o /path/to/template.yml /path/to/template.yml.tpl

• It will create a file /path/to/template.yml with the following content.

missing_var = ''

How to render a configuration on stdout.

• Create a file where you want /path/to/template.yml.tpl with the following content.

foobar="{{ foobar }}"

• Then launch the command below to render.

foobar='Hello world !' temply /path/to/template.yml.tpl

• It will output on stdout the following content.

foobar="Hello world !"

How to render a configuration with a json environment variable.

• Create a file where you want /path/to/template.json.tpl with the following content.

{{ json_var | fromjson }}
# Or {{ json_var | from_json }}

• Then launch the command below to render.

json_var='["string"]' temply /path/to/template.json.tpl

• It will output on stdout the following content.

["string"]

How to render a configuration with a yaml environment variable.

• Create a file where you want /path/to/template.yaml.tpl with the following content.

{{ (yaml_var | fromyaml).foo }}
# Or {{ (yaml_var | from_yaml).foo }}

• Then launch the command below to render.

yaml_var='foo: bar' temply /path/to/template.yaml.tpl

• It will output on stdout the following content.

bar

How to render a configuration with a wildcard environment variable.

• Create a file where you want /path/to/template.yml.tpl with the following content.

{% for key, value in environment('MY_') -%}
{{ key }} = {{ value }}
{% endfor %}

• Then launch the command below to render.

MY_FOO=foo MY_BAR=bar temply /path/to/template.yml.tpl

• It will output on stdout the following content.

BAR = bar
FOO = foo

How to render a configuration with an envdir.

• Create a file where you want /path/to/template.yml.tpl with the following content.

foobar="{{ FOOBAR }}"

• Then create an envdir with a file named FOOBAR with foobar as content.
• Then launch the command below to render.

temply --envdir /path/to/envdir /path/to/template.yml.tpl

• It will output on stdout the following content.

foobar = foobar

How to render a configuration with a dotenv file.

• Create a file where you want /path/to/template.yml.tpl with the following content.

foobar="{{ FOOBAR }}"

• Then create a dotenv file named dotenv with FOOBAR=foobar as content.
• Then launch the command below to render.

temply --dotenv /path/to/dotenv /path/to/template.yml.tpl

• It will output on stdout the following content.

foobar = foobar

How to render a configuration with a json file.

• Create a file where you want /path/to/template.yml.tpl with the following content.

foo="{{ FOO }}"
bar="{{ BAR }}"

• Then create a json file named file.json with the following content.

[
  {
    "key": "FOO",
    "value": "foo"
  },
  {
    "key": "BAR",
    "value": "bar"
  }
]

• Then launch the command below to render.

temply --json-file /path/to/file.json /path/to/template.yml.tpl

• It will output on stdout the following content.

foo="foo"
bar="bar"

How to render a configuration and keep template after rendering.

• By default, temply will remove template file.
• If you want to keep template you will have to use the flag --keep-template.

❤️ Contributing

If you find this project useful here's how you can help, please click the 👁️ Watch button to avoid missing notifications about new versions, and give it a 🌟 GitHub Star!

You can also contribute by:

• Sending a Pull Request with your awesome new features and bug fixed.
• Be part of the community and help resolve Issues.

🧾 License

The temply project is free and open-source software licensed under the Apache-2.0 license.