https://github.com/tanbro/jinjyaml

Application specific YAML tag of Jinja2 template
https://github.com/tanbro/jinjyaml

jinja jinja2 python template template-engine yaml yaml-tag

Last synced: 4 months ago
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Application specific YAML tag of Jinja2 template

• Host: GitHub
• URL: https://github.com/tanbro/jinjyaml
• Owner: tanbro
• License: bsd-3-clause
• Created: 2020-04-24T03:40:28.000Z (almost 5 years ago)
• Default Branch: master
• Last Pushed: 2024-07-07T05:27:52.000Z (7 months ago)
• Last Synced: 2024-10-15T04:24:00.228Z (4 months ago)
• Topics: jinja, jinja2, python, template, template-engine, yaml, yaml-tag
• Language: Python
• Homepage:
• Size: 121 KB
• Stars: 4
• Watchers: 4
• Forks: 0
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE
  • Authors: AUTHORS.md

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README

        
# jinjyaml

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[![Documentation Status](https://readthedocs.org/projects/jinjyaml/badge/?version=latest)](https://jinjyaml.readthedocs.io/en/latest/?badge=latest)

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[![Coverage](https://sonarcloud.io/api/project_badges/measure?project=tanbro_jinjyaml&metric=coverage)](https://sonarcloud.io/summary/new_code?id=tanbro_jinjyaml)

Application specific tag of [Jinja2][] template in [PyYAML][].

It may be useful if you only want to render special tag nodes in the document,

instead of whole YAML string as a template.

## Usage

### Example 1

1. Add `Jinja2` template constructor for tag `"!j2"`

   ```python

   import yaml

   import jinjyaml as jy

   ctor = jy.Constructor()

   yaml.add_constructor("!j2", ctor, yaml.SafeLoader)

   ```

1. create `YAML` file `1.yml`, with such contents:

   ```yaml

   array: !j2 |

     {% for i in range(n) %}

     - sub{{i}}: {{loop.index}}

     {% endfor %}

   ```

1. load and render the `YAML` file

   ```python

   with open("1.yml") as fp:

       data = yaml.load(fp, Loader=yaml.SafeLoader)

       # or for the short:

       # data = yaml.safe_load(fp)

   jy.extract(data, context={"n": 3}, inplace=True)

   print(data)

   ```

We'll get:

```json

{"array": [{"sub0": 1}, {"sub1": 2}, {"sub2": 3}]}

```

### Example 2

We have such YAML files:

- `sub-1.yml`:

  ```yaml

  "1.1": one

  "1.2": two

  ```

- `sub-2.yml`:

  ```yaml

  "2.1":

    "2.1.1": three

    "2.1.2": four

  ```

- `main.yml`:

  ```yaml

  foo: !j2 |

    {% filter indent %}

    {% include "sub-1.yml" %}

    {% endfilter %}

    {% filter indent %}

    {% include "sub-2.yml" %}

    {% endfilter %}

  ```

execute python code:

```python

from pprint import pprint

import jinja2

import jinjyaml as jy

import yaml

env = jinja2.Environment(loader=jinja2.FileSystemLoader("."))

ctor = jy.Constructor()

yaml.add_constructor("!j2", ctor, yaml.SafeLoader)

with open("main.yml") as fp:

    doc = yaml.safe_load(fp)

obj = jy.extract(doc, env)

pprint(obj)

```

We'll get:

```json

{"foo": {"1.1": "one",

         "1.2": "two",

         "2.1": {"2.1.1": "three", "2.1.2": "four"}}}

```

> **NOTE:**

>

> Since [Jinja2][]'s [`include`](https://jinja.palletsprojects.com/en/3.0.x/templates/#include) and [`indent`](https://jinja.palletsprojects.com/en/3.0.x/templates/#jinja-filters.indent) do not work very nice with indention languages like Python or YAML, it's not advised to use the feature in a complex case.

[jinja2]: https://jinja.palletsprojects.com/ "Jinja is a fast, expressive, extensible templating engine."

[pyyaml]: https://pyyaml.org/ "PyYAML is a full-featured YAML framework for the Python programming language."