The whylogs/WhyLabs Data Validator flavor provided with the ZenML integration uses whylogs and WhyLabs to generate and track data profiles, highly accurate descriptive representations of your data. The profiles can be used to implement automated corrective actions in your pipelines, or to render interactive representations for further visual interpretation, evaluation and documentation.

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When would you want to use it?

Whylogs is an open-source library that analyzes your data and creates statistical summaries called whylogs profiles. Whylogs profiles can be processed in your pipelines and visualized locally or uploaded to the WhyLabs platform, where more in depth analysis can be carried out. Even though whylogs also supports other data types, the ZenML whylogs integration currently only works with tabular data in pandas.DataFrame format. You should use the whylogs/WhyLabs Data Validator when you need the following data validation features that are possible with whylogs and WhyLabs:
  • Data Quality: validate data quality in model inputs or in a data pipeline
  • Data Drift: detect data drift in model input features
  • Model Drift: Detect training-serving skew, concept drift, and model performance degradation
You should consider one of the other Data Validator flavors if you need a different set of data validation features.

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How do you deploy it?

The whylogs Data Validator flavor is included in the whylogs ZenML integration, you need to install it on your local machine to be able to register a whylogs Data Validator and add it to your stack: 
zenml integration install whylogs -y
If you don’t need to connect to the WhyLabs platform to upload and store the generated whylogs data profiles, the Data Validator stack component does not require any configuration parameters. Adding it to a stack is as simple as running e.g.: 
# Register the whylogs data validator
zenml data-validator register whylogs_data_validator --flavor=whylogs

# Register and set a stack with the new data validator
zenml stack register custom_stack -dv whylogs_data_validator ... --set
Adding WhyLabs logging capabilities to your whylogs Data Validator is just slightly more complicated, as you also require a Secrets Manager in your stack to store the sensitive WhyLabs authentication information in a secure location. The WhyLabs credentials are configured as a ZenML secret that is referenced in the Data Validator configuration, e.g.: 
# Register the whylogs data validator
zenml data-validator register whylogs_data_validator --flavor=whylogs \
    --authentication_secret=whylabs_secret

# Register a secrets manager
zenml secrets-manager register secrets_manager \
    --flavor= ...

# Register and set a stack with the new data validator and secrets manager
zenml stack register custom_stack -dv whylogs_data_validator -x secrets_manager ... --set

# Create the secret referenced in the data validator
zenml secrets-manager secret register whylabs_secret -s whylogs \
    --whylabs_default_org_id= \
    --whylabs_api_key=
You’ll also need to enable whylabs logging for your custom pipeline steps if you want to upload the whylogs data profiles that they return as artifacts to the WhyLabs platform. This is enabled by default for the standard whylogs step.

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How do you use it?

Whylogs’s profiling functions take in a pandas.DataFrame dataset generate a DatasetProfileView object containing all the relevant information extracted from the dataset. There are three ways you can use whylogs in your ZenML pipelines that allow different levels of flexibility:
  • instantiate, configure and insert the standard WhylogsProfilerStep shipped with ZenML into your pipelines. This is the easiest way and the recommended approach, but can only be customized through the supported step configuration parameters.
  • call the data validation methods provided by the whylogs Data Validator in your custom step implementation. This method allows for more flexibility concerning what can happen in the pipeline step, but you are still limited to the functionality implemented in the Data Validator.
  • use the whylogs library directly in your custom step implementation. This gives you complete freedom in how you are using whylogs’s features.
Outside the pipeline workflow, you can use the ZenML whylogs visualizer to display the whylogs dashboards generated by your pipelines.

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The whylogs standard step

ZenML wraps the whylogs/WhyLabs functionality in the form of a standard WhylogsProfilerStep step. The only field in the step config is a dataset_timestamp attribute which is only relevant when you upload the profiles to WhyLabs that uses this field to group and merge together profiles belonging to the same dataset. The helper function whylogs_profiler_step used to create an instance of this standard step takes in an optional dataset_id parameter that is also used only in the context of WhyLabs upload to identify the model in the context of which the profile is uploaded, e.g.: 
from zenml.integrations.whylogs.steps import (
    WhylogsProfilerParameters,
    whylogs_profiler_step,
)

train_data_profiler = whylogs_profiler_step(
    step_name="train_data_profiler",
    params=WhylogsProfilerParameters(),
    dataset_id="model-2",
)
test_data_profiler = whylogs_profiler_step(
    step_name="test_data_profiler",
    params=WhylogsProfilerParameters(),
    dataset_id="model-3",
)
The step can then be inserted into your pipeline where it can take in a pandas.DataFrame dataset, e.g.: 
from zenml.pipelines import pipeline

@pipeline
def data_profiling_pipeline(
    data_loader,
    data_splitter,
    train_data_profiler,
    test_data_profiler,
):
    data, _ = data_loader()
    train, test = data_splitter(data)
    train_data_profiler(train)
    test_data_profiler(test)

p = data_profiling_pipeline(
    data_loader=data_loader(),
    data_splitter=data_splitter(),
    train_data_profiler=train_data_profiler,
    test_data_profiler=test_data_profiler,
)

p.run()
As can be seen from the step definition, the step takes in a dataset and returns a whylogs DatasetProfileView object: 
class WhylogsProfilerStep(BaseAnalyzerStep):
    """Generates a whylogs data profile from a given pd.DataFrame."""

    @staticmethod
    def entrypoint(  # type: ignore[override]
        dataset: pd.DataFrame,
        params: WhylogsProfilerParameters,
    ) -> DatasetProfileView:
        ...
You should consult the official whylogs documentation for more information on what you can do with the collected profiles. You can view the complete list of configuration parameters in the API docs. You can also check out our examples pages for working examples that use the whylogs standard step:

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The whylogs Data Validator

The whylogs Data Validator implements the same interface as do all Data Validators, so this method forces you to maintain some level of compatibility with the overall Data Validator abstraction, which guarantees an easier migration in case you decide to switch to another Data Validator. All you have to do is call the whylogs Data Validator methods when you need to interact with whylogs to generate data profiles. You may optionally enable whylabs logging to automatically upload the returned whylogs profile to WhyLabs, e.g.: 

import pandas as pd
from whylogs.core import DatasetProfileView
from zenml.integrations.whylogs.data_validators.whylogs_data_validator import (
    WhylogsDataValidator,
)
from zenml.integrations.whylogs.flavors.whylogs_data_validator_flavor import (
    WhylogsDataValidatorSettings,
)
from zenml.steps import step

whylogs_settings = WhylogsDataValidatorSettings(
    enable_whylabs=True, dataset_id=""
)

@step(
    settings = {
        "data_validator.whylogs": whylogs_settings
    }
)
def data_profiler(
    dataset: pd.DataFrame,
) -> DatasetProfileView:
    """Custom data profiler step with whylogs

    Args:
        dataset: a Pandas DataFrame

    Returns:
        Whylogs profile generated for the data
    """

    # validation pre-processing (e.g. dataset preparation) can take place here

    data_validator = WhylogsDataValidator.get_active_data_validator()
    profile = data_validator.data_profiling(
        dataset,
    )
    # optionally upload the profile to WhyLabs, if WhyLabs credentials are configured
    data_validator.upload_profile_view(profile)

    # validation post-processing (e.g. interpret results, take actions) can happen here

    return profile
Have a look at the complete list of methods and parameters available in the WhylogsDataValidator API in the API docs.

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Call whylogs directly

You can use the whylogs library directly in your custom pipeline steps, and only leverage ZenML’s capability of serializing, versioning and storing the DatasetProfileView objects in its Artifact Store. You may optionally enable whylabs logging to automatically upload the returned whylogs profile to WhyLabs, e.g.: 

import pandas as pd
from whylogs.core import DatasetProfileView
import whylogs as why
from zenml.steps import step
from zenml.integrations.whylogs.flavors.whylogs_data_validator_flavor import (
    WhylogsDataValidatorSettings,
)

whylogs_settings = WhylogsDataValidatorSettings(
    enable_whylabs=True, dataset_id=""
)

@step(
    settings = {
        "data_validator.whylogs": whylogs_settings
    }
)
def data_profiler(
    dataset: pd.DataFrame,
) -> DatasetProfileView:
    """Custom data profiler step with whylogs

    Args:
        dataset: a Pandas DataFrame

    Returns:
        Whylogs Profile generated for the dataset
    """

    # validation pre-processing (e.g. dataset preparation) can take place here

    results = why.log(dataset)
    profile = results.profile()

    # validation post-processing (e.g. interpret results, take actions) can happen here

    return profile.view()

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Using the whylogs ZenML Visualizer

In the post-execution workflow, you can load and render the whylogs profiles generated and returned by your pipeline steps by means of the ZenML whylogs Visualizer. The visualizer can take in a single step view, or two separate step views. In the first case, a visualization of a single data profile is rendered, in the second you will get a data drift report, e.g.: 
from zenml.integrations.whylogs.visualizers import WhylogsVisualizer
from zenml.post_execution import get_pipeline

def visualize_statistics(
    step_name: str, reference_step_name: Optional[str] = None
) -> None:
    """Helper function to visualize whylogs statistics from step artifacts.

    Args:
        step_name: step that generated and returned a whylogs profile
        reference_step_name: an optional second step that generated a whylogs
            profile to use for data drift visualization where two whylogs
            profiles are required.
    """
    pipe = get_pipeline(pipeline="data_profiling_pipeline")
    whylogs_step = pipe.runs[-1].get_step(step=step_name)
    whylogs_reference_step = None
    if reference_step_name:
        whylogs_reference_step = pipe.runs[-1].get_step(
            name=reference_step_name
        )

    WhylogsVisualizer().visualize(
        whylogs_step,
        reference_step_view=whylogs_reference_step,
    )

if __name__ == "__main__":
    visualize_statistics("data_loader")
    visualize_statistics("train_data_profiler", "test_data_profiler")
The whylogs profile will be displayed as a new tab in your browser, or rendered inline in your Jupyter notebook, depending on where you are running the code: Whylogs Visualization Example 1 Whylogs Visualization Example 2