Skip to main content
Version: Beta 🚧

Python Environments for On-Demand Feature Views

Public Preview

This feature is currently in Public Preview.

Build more powerful On-Demand Features like by leveraging popular Python packages available in Python Environments.

Python Environments for On-Demand Feature Views are isolated compute environments where transformations are run during Online feature retrieval. Specifying an environment enables the use of common Python libraries when building real-time features.

Available Python Environments

Tecton publishes a set of Python Environments that include with common feature transformation packages.

Python Environments are identified by a name and a version number, such as tecton-python-core:0.1. By pinning your environment, you can be sure that your transformation logic will continue to run reliably.

The following Python Environments are available for use:

  • tecton-python-core is a lightweight environment with the minimal set of dependencies available
  • tecton-python-extended offers a larger set of common feature transformation packages

The table below lists all available versions for these environments.

EnvironmentDate published

Specifying Environments for On-Demand Feature Views and Feature Services

The environments parameter on an On-Demand Feature View definition specifies the set of Environments that the transformation logic is compatible with. If the dependency required for your feature view is available in multiple environments, then you can include the set of environments in this list.

The on_demand_environment on the Feature Service definition specifies the single environment that will be used when running all On-Demand Feature Views in that Feature Service during Online retrieval.

For example, let’s say we have:

  • A Feature View with a dependency on numpy, which is available in both tecton-python-core:0.1 and tecton-python-extended:0.1.
  • A Feature View with a dependency on fuzzywuzzy, which is only available in tecton-python-extended:0.1
  • A Feature Service that contains both of these Feature Views
sources=[transaction_request, user_transaction_amount_metrics],
environments=["tecton-python-core:0.1", "tecton-python-extended:0.1", "my-new-env"],
def my_on_demand_feature_view_with_numpy(request, user_metrics):
import numpy


sources=[search_request, product_description],
environments=["tecton-python-extended:0.1", "my-new-env"],
def my_on_demand_feature_view_with_fuzzywuzzy(request, user_metrics):
import fuzzywuzzy


my_fs = FeatureService(
features=[my_on_demand_feature_view_with_numpy, my_on_demand_feature_view_with_fuzzywuzzy],

my_fs_2 = FeatureService(
features=[my_on_demand_feature_view_with_numpy, my_on_demand_feature_view_with_fuzzywuzzy],

Note that:

  • If environments is not specified for an On-Demand Feature View, then it is assumed to be compatible with all environments.
  • At execution time, all On-Demand Feature Views in a Feature Service must be run in the same Environment. As a result, the on_demand_environment specified by the Feature Service must be on the environments list for all On-Demand Feature Views included in the features list (or, they don’t specify any environments). Conversely, if an On-Demand Feature View specifies an environments constraint, then any Feature Service that includes the On-Demand Feature View must specify an on_demand_environment on that list.
  • Configuring an on_demand_environment can have an impact on get-features latency. See section below.

Configuring Notebook and Testing environments to be compatible with package requirements

The Environment configurations above are used only during the online execution of On-Demand Feature Views. In order to develop and test these Feature Views in offline environments, you’ll need to make sure any relevant dependencies are installed.

Below are our suggestions on how to configure offline environments, but there are other ways to achieve the same goal of having the appropriate dependencies installed.

Installing dependencies in your Notebook environment

Install individual packages in your notebook with %pip install. Alternatively, copy the full set of dependencies for the relevant version into a requirements.txt file to install all the dependencies at once.

Installing dependencies in your Unit Testing environment

In order to run unit tests for your On-Demand Feature Views with specific Python dependencies, ensure that the local Python environment executing the unit test have the proper dependency versions installed.

Impact of using Environments on get-features latency

The total latency observed is highly dependent on the complexity of the On-Demand Feature View transformation. For example, if the transformation contains sleep(1), then it will take at least 1 second to run.

Configuring the on_demand_environment for a Feature Service creates some per-request overhead on top of the transformation time when calling that Feature Service with the get-features API.

Executing transformations with an environment typically adds 20-50ms on top of the transformation time. This latency will be higher if there is a sudden spike in traffic, as the service scales to match the new load.

If the On-Demand Feature View includes another Feature View as a source, then it must wait for the upstream Feature View to return before executing, making the latency additive. Otherwise, the On-Demand Feature View will be executed in parallel with other Feature Views in the Feature Service.

To inspect the impact of your On-Demand Feature Views on the total latency of your get-features request, you can compare the serverTimeSeconds and sloServerTimeSeconds values in the metadataOptions response object. The serverTimeSeconds value represents the entire time it took for Tecton to fulfill the request, while the sloServerTimeSeconds measurement removes time spent on On-Demand Feature View execution.

Was this page helpful?

Happy React is loading...