In this article I will show how to prepare complete MLOPS solution based on the Feast feature store and MLflow platform.

Before you will continue reading please watch short introduction:

The whole solution will be deployed on the kubernetes (mlflow_feast.yaml).

We will use:
* Feast – as a Feature Store
* MLflow – as model repository
* Minio – as a S3 storage
* Jupyter notebook – as a workspace
* Redis – for a online features store

To better visualize the whole process we will use the Propensity to buy example where I base on the Kaggle examples and data.

We start in Jupyter Notebook where we prepare Feast feature store schema which is kept in S3.

We can simply inspect the Feast schema in Jupyter Notebook:

from feast import FeatureStore
from IPython.core.display import display, HTML
import json
from json2html import *
import warnings
warnings.filterwarnings('ignore')

class FeastSchema:
    def __init__(self, repo_path: str):
        self.store = FeatureStore(repo_path=repo_path)

    def show_schema(self, skip_meta: bool= False):
        feast_schema=self.__project_show_schema(skip_meta)        
        display(HTML(json2html.convert(json = feast_schema)))

    def show_table_schema(self, table: str, skip_meta: bool= False):
        feasture_tables_dictionary=self.__project_show_schema(skip_meta)
        display(HTML(json2html.convert(json = {table:feasture_tables_dictionary[table]})))

    def __project_show_schema(self, skip_meta: bool= False):
        entities_dictionary={}
        feast_entities=self.store.list_entities()
        for entity in feast_entities:
            entity_dictionary=entity.to_dict()
            entity_spec=entity_dictionary['spec']
            entities_dictionary[entity_spec['name']]=entity_spec

        feasture_tables_dictionary={}
        feast_feature_tables=self.store.list_feature_views()
        for feature_table in feast_feature_tables:
            feature_table_dict=json.loads(str(feature_table))
            feature_table_spec=feature_table_dict['spec']
            feature_table_name=feature_table_spec['name']
            feature_table_spec.pop('name',None)
            if 'entities' in feature_table_spec:
                feature_table_entities=[]
                for entity in feature_table_spec['entities']:
                    feature_table_entities.append(entities_dictionary[entity])
                feature_table_spec['entities']=feature_table_entities

            if not skip_meta:
                feature_table_spec['meta']=feature_table_dict['meta']
            else:
                feature_table_spec.pop('input',None)
                feature_table_spec.pop('ttl',None)
                feature_table_spec.pop('online',None)

            feasture_tables_dictionary[feature_table_name]=feature_table_spec

        return feasture_tables_dictionary




FeastSchema(".").show_schema()
#FeastSchema(".").show_schema(skip_meta=True)
#FeastSchema(".").show_table_schema('driver_hourly_stats')
#FeastSchema().show_tables()

In our case we store the data in Apache Parquet files in S3 bucket.
Using the Feast we can fetch the historical features and train the model using Scikit-learn library

bucket_name="propensity"
filename="training_sample"

store = FeatureStore(repo_path=".")

s3 = fs.S3FileSystem(endpoint_override=os.environ.get("FEAST_S3_ENDPOINT_URL"))
entity_df=pd.read_parquet(f'{bucket_name}/{filename}_entities.parquet', filesystem=s3)
entity_df["event_timestamp"]=datetime.now()


training_df = store.get_historical_features(
    entity_df=entity_df, 
    feature_refs = [
        'propensity_data:basket_icon_click',
        'propensity_data:basket_add_list',
        'propensity_data:basket_add_detail',
        'propensity_data:sort_by',
        'propensity_data:image_picker',
        'propensity_data:account_page_click',
        'propensity_data:promo_banner_click',
        'propensity_data:detail_wishlist_add',
        'propensity_data:list_size_dropdown',
        'propensity_data:closed_minibasket_click',
        'propensity_data:checked_delivery_detail',
        'propensity_data:checked_returns_detail',
        'propensity_data:sign_in',
        'propensity_data:saw_checkout',
        'propensity_data:saw_sizecharts',
        'propensity_data:saw_delivery',
        'propensity_data:saw_account_upgrade',
        'propensity_data:saw_homepage',
        'propensity_data:device_mobile',
        'propensity_data:device_computer',
        'propensity_data:device_tablet',
        'propensity_data:returning_user',
        'propensity_data:loc_uk',
        'propensity_data:ordered'
    ],
).to_df()

predictors = training_df.drop(['propensity_data__ordered','UserID','event_timestamp'], axis=1)
targets = training_df['propensity_data__ordered']

X_train, X_test, y_train, y_test = train_test_split(predictors, targets, test_size=.3)

classifier=GaussianNB(var_smoothing=input_params['var_smoothing'])
classifier=classifier.fit(X_train,y_train)

predictions=classifier.predict(X_test)

conf_matrix=sklearn.metrics.confusion_matrix(y_test,predictions)
ac_score=sklearn.metrics.accuracy_score(y_test, predictions)

propensity_model_path = 'propensity.joblib'
joblib.dump(classifier, propensity_model_path)

artifacts = {
    "propensity_model": propensity_model_path,
    "feature_store": "feature_store.yaml"
}

The model will use online Feast redis features as well as additional features from the request thus we need to wrap the MLflow model and define it:

import mlflow.pyfunc
class PropensityWrapper(mlflow.pyfunc.PythonModel):

    def load_context(self, context):
        import joblib
        from feast import FeatureStore
        import pandas as pd 
        import os

        self.model = joblib.load(context.artifacts["propensity_model"])
        self.store = FeatureStore(repo_path=os.environ.get("FEAST_REPO_PATH"))

    def predict(self, context, model_input):
        users=list(model_input.to_dict()["UserID"].values())

        feature_vector = self.store.get_online_features(
            feature_refs=[
                'propensity_data:basket_icon_click',
                'propensity_data:basket_add_list',
                'propensity_data:basket_add_detail',
                'propensity_data:sort_by',
                'propensity_data:image_picker',
                'propensity_data:account_page_click',
                'propensity_data:promo_banner_click',
                'propensity_data:detail_wishlist_add',
                'propensity_data:list_size_dropdown',
                'propensity_data:closed_minibasket_click',
                'propensity_data:checked_delivery_detail',
                'propensity_data:checked_returns_detail',
                'propensity_data:sign_in',
                'propensity_data:saw_checkout',
                'propensity_data:saw_sizecharts',
                'propensity_data:saw_delivery',
                'propensity_data:saw_account_upgrade',
                'propensity_data:saw_homepage',
                'propensity_data:returning_user',
                'propensity_data:loc_uk'
            ],
            entity_rows=[{"UserID": uid} for uid in users]
        ).to_dict()

        data=pd.DataFrame.from_dict(feature_vector)
        merged_data = pd.merge(model_input,data, how="inner", on=["UserID"], suffixes=('_x', '')).drop(['UserID'], axis=1)
        return self.model.predict(merged_data)

Now we can log the MLflow model to the repository:

import warnings
import sys

import pandas as pd
import numpy as np
from sklearn.metrics import mean_squared_error, mean_absolute_error, r2_score
from sklearn.model_selection import train_test_split
from sklearn.linear_model import ElasticNet
from urllib.parse import urlparse
import mlflow
import mlflow.sklearn
import mlflow.pyfunc

#conda_env=mlflow.pyfunc.get_default_conda_env()

with mlflow.start_run():

    #mlflow.log_param("var_smoothing", input_params['var_smoothing'])
    mlflow.log_metric("accuracy_score", ac_score)

    tracking_url_type_store = urlparse(mlflow.get_tracking_uri()).scheme

    if tracking_url_type_store != "file":
        mlflow.pyfunc.log_model("model",
                                 registered_model_name="propensity_model",
                                 python_model=PropensityWrapper(),
                                 artifacts=artifacts,
                                 conda_env=conda_env)
    else:
        mlflow.pyfunc.log_model("model",
                                 path=my_model_path,
                                 python_model=PropensityWrapper(),
                                 artifacts=artifacts,
                                 conda_env=conda_env)

We can export the code and run is using MLflow cli:

mlflow run . --no-conda --experiment-name="propensity" -P var_smoothing=1e-9

Now we need to materialize features to Redis:

feast materialize 2021-03-22T23:42:00 2021-06-22T23:42:00

Using MLflow we can simply deploy model as a microservice in k8s.
In our case we want to deploy the model models:/propensity_model/Production
which is currently assigned for Production. During start the MLflow will automatically fetch the proper model from S3:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: mlflow-serving
  namespace: qooba
spec:
  replicas: 1
  selector:
    matchLabels:
      app: mlflow-serving
      version: v1
  template:
    metadata:
      labels:
        app: mlflow-serving
        version: v1
    spec:
      containers:
      - image: qooba/mlflow:serving
        imagePullPolicy: IfNotPresent
        name: mlflow-serving
        env:
        - name: MLFLOW_TRACKING_URI
          value: http://mlflow.qooba.svc.cluster.local:5000
        - name: AWS_ACCESS_KEY_ID
          valueFrom:
            secretKeyRef:
              name: minio-auth
              key: username
        - name: AWS_SECRET_ACCESS_KEY
          valueFrom:
            secretKeyRef:
              name: minio-auth
              key: password
        - name: MLFLOW_S3_ENDPOINT_URL
          value: http://minio.qooba.svc.cluster.local:9000
        - name: FEAST_S3_ENDPOINT_URL
          value: http://minio.qooba.svc.cluster.local:9000
        - name: REDIS_TYPE
          value: REDIS
        - name: REDIS_CONNECTION_STRING
          value: redis.qooba.svc.cluster.local:6379,db=0
        - name: FEAST_TELEMETRY
          value: "false"
        - name: FEAST_REPO_PATH
          value: /feast_repository
        - name: PORT
          value: "5000"
        - name: MODEL
          value: models:/propensity_model/Production
        ports:
        - containerPort: 5000
        volumeMounts:
          - mountPath: /feast_repository
            name: config
      volumes:
        - name: config
          configMap:
            name: mlflow-serving
            items:
            - key: feature_store
              path: feature_store.yaml

On each HTTP request:

import requests
import json

url="http://mlflow-serving.qooba.svc.cluster.local:5000/invocations"

headers={
    'Content-Type': 'application/json; format=pandas-records'
}

data=[
    {"UserID": "a720-6b732349-a720-4862-bd21-644732",
     'propensity_data:device_mobile': 1.0,
     'propensity_data:device_computer': 0.0,
     'propensity_data:device_tablet': 0.0
    }
]

response=requests.post(url, data=json.dumps(data), headers=headers)
response.text

The model will fetch the client features (based on UserID) from Redis and HTTP request and generate prediction.