doc: Custom Error Handling (#4811)

docs/source/guides/error-handling.rst

@@ -0,0 +1,38 @@
+=============
+Error Handling
+=============
+BentoML allows user to define custom error handling logic for their Service.
+
+This document describes how to define a custom exception class and error handling logic in a BentoML Service.
+
+Custom Exception Class
+-----------------------
+User can define custom exception class by inheriting from `BentoMLException` or any of its subclasses, such as `InvalidArgument` in the example below.
+
+.. note::
+
+   Error Code 401, 403, and >500 is reserved by BentoML, user should not use these error codes in their custom exception class.
+
+.. code-block:: python
+
+    import bentoml
+    from bentoml.exceptions import InvalidArgument, BentoMLException
+    from http import HTTPStatus
+
+    class MyCustomException(BentoMLException):
+        error_code = HTTPStatus.METHOD_NOT_ALLOWED
+
+    class MyCustomInvalidArgsException(InvalidArgument):
+        pass
+
+
+    @bentoml.service
+    class MyService:
+
+        @bentoml.api
+        def test1(self, text: str) -> str:
+            raise MyCustomException("this is a custom error message")
+
+        @bentoml.api
+        def test2(self, text: str) -> str:
+            raise MyCustomInvalidArgsException("this is a custom error message")

docs/source/guides/index.rst

@@ -115,7 +115,13 @@ This chapter introduces the key features of BentoML. We recommend you read :doc:
         :link: /guides/lifecycle-hooks
         :link-type: doc
 
-        Confgiure hooks to run custom logic at different stages of a Service's lifecycle.
+        Configure hooks to run custom logic at different stages of a Service's lifecycle.
+
+    .. grid-item-card:: :doc:`/guides/error-handling`
+        :link: /guides/error-handling
+        :link-type: doc
+
+        Define Custom Error Handling Logic for your BentoML Service.
 
 .. toctree::
     :hidden: