cognite-pygen 0.9.0

Cognite GraphQL Python Generation SDK

Cognite GraphQL Python Generator

This is the Cognite GraphQL Python Generator, pygen. The purpose of this package is to help developers to work with Cognite Data Fusion's (CDF) Data Models (DM) in Python.

[DISCLAIMER!] This project is in a highly experimental state and no guarantees are made for consistency between versions. The project may also become deprecated if the experimentation turns out to be a dead end.

The core functionality is to provide a Python client that matches a data model. This enables the developer for the following benefits

• Client side validation of the data before writing it to CDF.
• Autocompletion is matching the data model in the integrated developer environment (IDE). This is important as it enables:
  • Discoverability of a data model through Python.
  • Reduced typing errors in development.
• Keeping the language domain specific for the developer. Instead of working with generic concepts such as instances, nodes, edges, the developer can work with the concepts in the data model.

Installation

Without any optional dependencies

To install this package without CLI support:

pip install cognite-pygen

With optional dependencies

• cli This includes CLI support such that you can run the package from the command line.

pip install cognite-pygen[cli]

Usage

The goal of the package is to have representations of all the types in a given data model with API calls to .list(), .apply(), .delete(), and .retrieve() individuals for each type.

With CLI

You can specify the data models either as a .graphql schema or a pydantic classes in a .py file. Then, you can use the CLI to automatically generate the other representation as well as the client.py file which creates the API and the convenience method get_[client_name]_client().

To generate from a .graphql schema you use the following command.

pygen topython 'PATH_TO_SCHEMA'

This will create a schema.py and a client.py file in the directory you are running the command.

To generate from schema.py use the following command

pygen togql 'PATH_TO_FILE'

This will load the python module and create a schema.graphql file in the directory you are running the command.

PATH_TO_FILE can be either a path to a .py file or a Python dot-notation to a package (e.g. my_project.schema_module make sure that the package in which case the module must be in Python path).

Note the schema.py file must follow a specific structure, see examples/cinematography_domain for an example. The overall structure is as follows:

1. Instantiate a new schema with the line, myschema: Schema[DomainModel] = Schema()
2. Register all you Types with @myschema.register_type
3. Close the schema with myschema.close()

To get a concrete example is available in examples/cinematography_domain, it consists of four files.

• schema.graphql The schema defined in GraphQL language.
• schema.py The schema defined in pydantic classes.
• client.py Which sets up the client for the data model.
• usage.py Demonstrates the usage of the client.

Without CLI

You can run this package directly in Python code. This can be useful, for example, a notebook. When you run the function to_client_sdk you get a PythonSDK object back which has the pydantic classes in a PythonSDK.schema and the client in the PythonSDK.client.

from cognite.pygen import to_client_sdk
my_schema = """type Case {
  scenario: Scenario
  start_time: String!
  end_time: String!
 }

type Scenario {
  name: String!
}
"""
sdk = to_client_sdk(my_schema, "MyClient", "my_schema")
print(sdk.schema)

Settings File

gypen togql and pygen topython take their defaults form settings.toml if present. See settings.toml for an example, section [local] is relevant for togql and topython commands.

DM Non-GraphQl API

The API developed is based on the non-GraphQL endpoints in Data Model API v3. There is a simplified wrapper which is available in cognite.pygen.dm_clients.

See dm_clients/README.md for more details.__

Changelog

Wondering about previous changes to the SDK? Take a look at the CHANGELOG.

Contributing

Want to contribute? Check out CONTRIBUTING.