Add documentation for custom template

[koxudaxi]

There is no document of the custom template. We should write a document on how to use the feature.

Related issues

https://github.com/koxudaxi/datamodel-code-generator/issues/144

[camerondavison]

I was wanting to add https://github.com/snowplow/snowplow-python-tracker/blob/master/snowplow_tracker/self_describing_json.py to the template somehow, but did not really find any way to make that happen. so it would be nice to have some documentation around extending things

[koxudaxi]

@camerondavison Thank you for your comment.

I was wanting to add https://github.com/snowplow/snowplow-python-tracker/blob/master/snowplow_tracker/self_describing_json.py to the template somehow,

Sorry, What did you want? Did you want to inherit the class?

[camerondavison]

I think maybe I want to wrap it in that class. Since I need to write the schema field and the model is the data.

[koxudaxi]

@camerondavison I don't know how to use snowplow-python-tracker. Do you want this output?

from pydantic import BaseModel

class Model(BaseModel):
    # inject schema path when generate this model
    _schema_path: str = "iglu:com.acme/viewed_product/jsonschema/2-0-2"

    product_id: int = "ASO01043"
    price: float = 49.95
    walrus: int = 1000

    def to_json(self):
        return {
            "schema": self._schema_path,
            "data": self.dict()
        }

    def to_string(self):
        import json
        return json.dumps(self.to_json())

print(Model().to_string())
# {"schema": "iglu:com.acme/viewed_product/jsonschema/2-0-2", "data": {"product_id": "ASO01043", "price": 49.95, "walrus": 1000}}

Otherwise, Would you please write an example of the output that you expect here?

[camerondavison]

Yes that is what I want.

[koxudaxi]

@camerondavison Unfortunately, This code-generator can't output the schema path. But, This viewpoint looks good. I will implement it after we resolve other issues.

[koxudaxi]

I added https://koxudaxi.github.io/datamodel-code-generator/custom_template/