docs and updates

Signed-off-by: Achal Shah <achals@gmail.com>
feast-dev · feast-ci-bot · Jul 22, 2021 · Jul 6, 2021 · Jul 6, 2021 · Jul 6, 2021
commit e3cebc13aa78748edf6945fed4afa1f619033b83
@@ -0,0 +1,29 @@
+# Feature Service
+
+### Feature Service
+
+A feature service is an object that represents a logical group of features from one or more [feature views](feature-view.md). 
+Feature Services allows features from within a feature view to be used as needed by an ML model. Users can expect to create one Feature Service per Model, keeping the features needed by the model tracked.   
+
+{% tabs %}
+{% tab title="driver\_trips\_feature\_service.py" %}
+```python
+from driver_trips_feature_view import driver_stats_fv
+
+driver_stats_fs = FeatureService(
+    name="driver_activity",
+    features=[driver_stats_fv]
+)
+```
+{% endtab %}
+{% endtabs %}
+
+Feature services are used during
+
+* The generation of training datasets when querying feature views in order to find historical feature values. A single training dataset may consist of features from multiple feature views.
+* Retrieval of features from the online store. Feature services provide the schema definition to Feast in order to look up features from the online store.
+
+{% hint style="info" %}
+Feast does not currently spin up any servers to serve these features.
+{% endhint %}
+
@@ -17,8 +17,8 @@
 
 class FeatureService:
     """
-    A FeatureService object is used to group features together for retrieval.
-    The features may all be part of the same Feature view, or from a combination of Feature views.
+    A feature service allows users to group features together for retrieval.
+    The features may all be part of the same feature view, or from a combination of feature views.
 
     """
 
@@ -36,10 +36,12 @@ def __init__(
     ):
         """
         Create a new Feature Service object.
-        :param name: A unique name for the Feature Service.
-        :param features: A list of Features that are grouped as part of this FeatureService.
-            The list may contain Feature Views, Feature Tables, or a subset of either.
-        :param tags: A dictionary of key-value pairs used for organizing Feature Services.
+
+        Args:
+            name: A unique name for the Feature Service.
+            features: A list of Features that are grouped as part of this FeatureService.
+                The list may contain Feature Views, Feature Tables, or a subset of either.
+            tags: A dictionary of key-value pairs used for organizing Feature Services.
         """
         self.name = name
         self.features = []