Integrate Fiddler with Databricks for Model Monitoring and Explainability

Fiddler allows your team to monitor, explain and analyze your models developed and deployed in Databricks Workspace by integrating with MLflow for model asset management and utilizing Databricks Spark environment for data management.

To validate and monitor models built on Databricks using Fiddler, you can follow these steps:

1. Create a Fiddler project

2. Create a Fiddler model using sample data or model information from MLflow

3. Publish production data streaming live or in batches

Prerequisites

This guide assumes you have:

• A Databricks account and valid credentials

• A Fiddler environment with an account and valid credentials

• Know how to connect and use use the Fiddler Python client

Begin with a Databricks Notebook

Launch a Databricks notebook from your workspace and run the following code:

!pip install -q fiddler-client
import fiddler as fdl

Now that you have the Fiddler library installed, you can connect to your Fiddler environment. You will need your authentication token from the Credentials tab in Application Settings.

URL = ""
AUTH_TOKEN = ""
fdl.init(url: str, token: str)

Finally, you can set up a new project using:

# The project.id is required when creating models
project = fdl.Project(name='YOUR_PROJECT_NAME')
project.create()

Creating the Fiddler Model

Quickest Option: Let Fiddler Automate Model Creation

The quickest way to onboard a Fiddler model is to get a sample of data from which Fiddler can infer model schema and metadata. Ideally you will have baseline, testing, or training data that is representative of your model schema. Fiddler can infer your model schema from this sample dataset. You can download baseline or training data from a delta table and share it with Fiddler as a baseline dataset:

sample_dataset = spark.read.table("YOUR_DATASET").select("*").toPandas()

Now that you have sample data, you can create a Fiddler model easily as documented here and demonstrated in our Simple Monitoring Quick Start Guide. A rough outline of the steps follow:

# Define a ModelSpec which tells Fiddler what role each column 
# in your model schema serves.
model_spec = fdl.ModelSpec(
  inputs=['feature_input_column', ...],
  outputs=['output_column'],
  targets=['label_column'],
  metadata=['id_column', 'data_segment_column', ...],
)

# Identify the task your ML model performs as Fiddler will use this
# to generate the performance metrics appropriate to the task. 
# ModelTask.NOT_SET is also an option if performance metrics are not needed.
model_task = fdl.ModelTask.BINARY_CLASSIFICATION
task_params = fdl.ModelTaskParams(target_class_order=['no', 'yes'])

# Use Model.from_data() to define your model's ModelSchema automatically by
# passing the sample_dataset in the source parameter for schema inference.
model = fdl.Model.from_data(
    name='name_for_display_in_Fiddler',
    project_id=project.id,
    source=sample_dataset,
    spec=model_spec,
    task=model_task,
    task_params=task_params,
    event_id_col='your_unique_event_id_column',
    event_ts_col='event_timestamp_column'
)
# Create the model in Fiddler
model.create()

Option: Using the MLflow Model Registry

Another option is manually construct your model's schema from the details contained in the MLflow registry. Using the MLflow API you can query the model registry and get the model signature which describes the inputs and outputs as a dictionary. You can use this dictionary to build out the Model, ModelSchema, and ModelSpec objects which defines the tabular schema of your model.

import mlflow 
from mlflow.tracking import MlflowClient

# Initiate MLFlow Client 
client = MlflowClient()

# Get the model URI
model_version_info = client.get_model_version(model_name, model_version)
model_uri = client.get_model_version_download_uri(model_name, model_version_info) 

#Get the Model Signature
mlflow_model_info = mlflow.models.get_model_info(model_uri)
model_inputs_schema = model_info.signature.inputs.to_dict()
model_inputs = [ sub['name'] for sub in model_inputs_schema ]

Refer to this example notebook in GitHub which demonstrates manually defining your Fiddler model's schema.

Publishing Events

Now you can publish all the events from your models. You can do this in two ways:

Batch Models

If your models run batch processes with your models or your aggregate model outputs over a time frame, then you can use the table change feed from Databricks to select only the new events and send them to Fiddler:

import fiddler as fdl
from pyspark.sql import SparkSession

# Get the active Spark session
spark = SparkSession.builder.getOrCreate()

changes_df = (
    spark.read.format("delta")
    .option("readChangeFeed", "true")
    .option("startingVersion", last_version)
    .option("endingVersion", new_version)
    .table("inferences")
    .toPandas()
)

# Assumes an initialized Python client session and instantiated Model
job = model.publish(
    source=changes_df,
    environment=fdl.EnvType.PRODUCTION,
)
print(f'Initiated Production dataset upload with Job ID = {job.id}')

Live Models

For models with live predictions or real-time applications, you can add the following code snippet to your prediction pipeline and send every event to Fiddler in real-time:

# Turn your model's output in a pandas dataframe
example_event = model_output.toJSON().map(lambda x: json.loads(x)).collect()

# Assumes an initialized Python client session and instantiated Model
event_id = model.publish(
    source=example_event,
    environment=fdl.EnvType.PRODUCTION,
)
print(f'Published {event_id_list}')