[App] Improve the autoscaler UI (#16063)

[App] Improve the autoscaler UI (#16063)

(cherry picked from commit 39d27f6)

docs/source-app/api_references.rst

@@ -45,7 +45,7 @@ ___________________
     ~multi_node.lite.LiteMultiNode
     ~multi_node.pytorch_spawn.PyTorchSpawnMultiNode
     ~multi_node.trainer.LightningTrainerMultiNode
-    ~auto_scaler.AutoScaler
+    ~serve.auto_scaler.AutoScaler
 
 ----
 

examples/app_server_with_auto_scaler/app.py

@@ -1,5 +1,5 @@
 # ! pip install torch torchvision
-from typing import Any, List
+from typing import List
 
 import torch
 import torchvision
@@ -8,16 +8,12 @@
 import lightning as L
 
 
-class RequestModel(BaseModel):
-    image: str  # bytecode
-
-
 class BatchRequestModel(BaseModel):
-    inputs: List[RequestModel]
+    inputs: List[L.app.components.Image]
 
 
 class BatchResponse(BaseModel):
-    outputs: List[Any]
+    outputs: List[L.app.components.Number]
 
 
 class PyTorchServer(L.app.components.PythonServer):
@@ -81,8 +77,8 @@ def scale(self, replicas: int, metrics: dict) -> int:
         max_replicas=4,
         autoscale_interval=10,
         endpoint="predict",
-        input_type=RequestModel,
-        output_type=Any,
+        input_type=L.app.components.Image,
+        output_type=L.app.components.Number,
         timeout_batching=1,
         max_batch_size=8,
     )

pyproject.toml

@@ -79,8 +79,8 @@ module = [
     "lightning_app.components.serve.types.image",
     "lightning_app.components.serve.types.type",
     "lightning_app.components.serve.python_server",
+    "lightning_app.components.serve.auto_scaler",
     "lightning_app.components.training",
-    "lightning_app.components.auto_scaler",
     "lightning_app.core.api",
     "lightning_app.core.app",
     "lightning_app.core.flow",

src/lightning_app/CHANGELOG.md

@@ -11,6 +11,8 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 
 - Added partial support for fastapi `Request` annotation in `configure_api` handlers ([#16047](https://github.com/Lightning-AI/lightning/pull/16047))
 
+- Added a nicer UI with URL and examples for the autoscaler component ([#16063](https://github.com/Lightning-AI/lightning/pull/16063))
+
 - Added more datatypes to serving component ([#16018](https://github.com/Lightning-AI/lightning/pull/16018))
 
 - Added `work.delete` method to delete the work ([#16103](https://github.com/Lightning-AI/lightning/pull/16103))

src/lightning_app/components/__init__.py

@@ -1,4 +1,3 @@
-from lightning_app.components.auto_scaler import AutoScaler
 from lightning_app.components.database.client import DatabaseClient
 from lightning_app.components.database.server import Database
 from lightning_app.components.multi_node import (
@@ -9,6 +8,7 @@
 )
 from lightning_app.components.python.popen import PopenPythonScript
 from lightning_app.components.python.tracer import Code, TracerPythonScript
+from lightning_app.components.serve.auto_scaler import AutoScaler
 from lightning_app.components.serve.gradio import ServeGradio
 from lightning_app.components.serve.python_server import Category, Image, Number, PythonServer, Text
 from lightning_app.components.serve.serve import ModelInferenceAPI

src/lightning_app/components/serve/__init__.py

@@ -1,5 +1,6 @@
+from lightning_app.components.serve.auto_scaler import AutoScaler
 from lightning_app.components.serve.gradio import ServeGradio
 from lightning_app.components.serve.python_server import Category, Image, Number, PythonServer, Text
 from lightning_app.components.serve.streamlit import ServeStreamlit
 
-__all__ = ["ServeGradio", "ServeStreamlit", "PythonServer", "Image", "Number", "Category", "Text"]
+__all__ = ["ServeGradio", "ServeStreamlit", "PythonServer", "Image", "Number", "Category", "Text", "AutoScaler"]

src/lightning_app/components/auto_scaler.py → src/lightning_app/components/serve/auto_scaler.py

@@ -6,7 +6,7 @@
 import uuid
 from base64 import b64encode
 from itertools import cycle
-from typing import Any, Dict, List, Tuple, Type
+from typing import Any, Dict, List, Optional, Tuple, Type
 
 import requests
 import uvicorn
@@ -15,11 +15,13 @@
 from fastapi.responses import RedirectResponse
 from fastapi.security import HTTPBasic, HTTPBasicCredentials
 from pydantic import BaseModel
+from starlette.staticfiles import StaticFiles
 from starlette.status import HTTP_401_UNAUTHORIZED
 
 from lightning_app.core.flow import LightningFlow
 from lightning_app.core.work import LightningWork
 from lightning_app.utilities.app_helpers import Logger
+from lightning_app.utilities.cloud import is_running_in_cloud
 from lightning_app.utilities.imports import _is_aiohttp_available, requires
 from lightning_app.utilities.packaging.cloud_compute import CloudCompute
 
@@ -114,20 +116,21 @@ class _LoadBalancer(LightningWork):
             requests to be batched. In any case, requests are processed as soon as `max_batch_size` is reached.
         timeout_keep_alive: The number of seconds until it closes Keep-Alive connections if no new data is received.
         timeout_inference_request: The number of seconds to wait for inference.
-        \**kwargs: Arguments passed to :func:`LightningWork.init` like ``CloudCompute``, ``BuildConfig``, etc.
+        **kwargs: Arguments passed to :func:`LightningWork.init` like ``CloudCompute``, ``BuildConfig``, etc.
     """
 
     @requires(["aiohttp"])
     def __init__(
         self,
-        input_type: BaseModel,
-        output_type: BaseModel,
+        input_type: Type[BaseModel],
+        output_type: Type[BaseModel],
         endpoint: str,
         max_batch_size: int = 8,
         # all timeout args are in seconds
-        timeout_batching: int = 1,
+        timeout_batching: float = 1,
         timeout_keep_alive: int = 60,
         timeout_inference_request: int = 60,
+        work_name: Optional[str] = "API",  # used for displaying the name in the UI
         **kwargs: Any,
     ) -> None:
         super().__init__(cloud_compute=CloudCompute("default"), **kwargs)
@@ -142,6 +145,7 @@ def __init__(
         self._batch = []
         self._responses = {}  # {request_id: response}
         self._last_batch_sent = 0
+        self._work_name = work_name
 
         if not endpoint.startswith("/"):
             endpoint = "/" + endpoint
@@ -280,6 +284,14 @@ async def update_servers(servers: List[str], authenticated: bool = Depends(authe
         async def balance_api(inputs: self._input_type):
             return await self.process_request(inputs)
 
+        endpoint_info_page = self._get_endpoint_info_page()
+        if endpoint_info_page:
+            fastapi_app.mount(
+                "/endpoint-info", StaticFiles(directory=endpoint_info_page.serve_dir, html=True), name="static"
+            )
+
+        logger.info(f"Your load balancer has started. The endpoint is 'http://{self.host}:{self.port}{self.endpoint}'")
+
         uvicorn.run(
             fastapi_app,
             host=self.host,
@@ -332,6 +344,60 @@ def send_request_to_update_servers(self, servers: List[str]):
         response = requests.put(f"{self.url}/system/update-servers", json=servers, headers=headers, timeout=10)
         response.raise_for_status()
 
+    @staticmethod
+    def _get_sample_dict_from_datatype(datatype: Any) -> dict:
+        if not hasattr(datatype, "schema"):
+            # not a pydantic model
+            raise TypeError(f"datatype must be a pydantic model, for the UI to be generated. but got {datatype}")
+
+        if hasattr(datatype, "_get_sample_data"):
+            return datatype._get_sample_data()
+
+        datatype_props = datatype.schema()["properties"]
+        out: Dict[str, Any] = {}
+        lut = {"string": "data string", "number": 0.0, "integer": 0, "boolean": False}
+        for k, v in datatype_props.items():
+            if v["type"] not in lut:
+                raise TypeError("Unsupported type")
+            out[k] = lut[v["type"]]
+        return out
+
+    def get_code_sample(self, url: str) -> Optional[str]:
+        input_type: Any = self._input_type
+        output_type: Any = self._output_type
+
+        if not (hasattr(input_type, "request_code_sample") and hasattr(output_type, "response_code_sample")):
+            return None
+        return f"{input_type.request_code_sample(url)}\n{output_type.response_code_sample()}"
+
+    def _get_endpoint_info_page(self) -> Optional["APIAccessFrontend"]:  # noqa: F821
+        try:
+            from lightning_api_access import APIAccessFrontend
+        except ModuleNotFoundError:
+            logger.warn("APIAccessFrontend not found. Please install lightning-api-access to enable the UI")
+            return
+
+        if is_running_in_cloud():
+            url = f"{self._future_url}{self.endpoint}"
+        else:
+            url = f"http://localhost:{self.port}{self.endpoint}"
+
+        frontend_objects = {"name": self._work_name, "url": url, "method": "POST", "request": None, "response": None}
+        code_samples = self.get_code_sample(url)
+        if code_samples:
+            frontend_objects["code_samples"] = code_samples
+            # TODO also set request/response for JS UI
+        else:
+            try:
+                request = self._get_sample_dict_from_datatype(self._input_type)
+                response = self._get_sample_dict_from_datatype(self._output_type)
+            except TypeError:
+                return None
+            else:
+                frontend_objects["request"] = request
+                frontend_objects["response"] = response
+        return APIAccessFrontend(apis=[frontend_objects])
+
 
 class AutoScaler(LightningFlow):
     """The ``AutoScaler`` can be used to automatically change the number of replicas of the given server in
@@ -403,8 +469,8 @@ def __init__(
         max_batch_size: int = 8,
         timeout_batching: float = 1,
         endpoint: str = "api/predict",
-        input_type: BaseModel = Dict,
-        output_type: BaseModel = Dict,
+        input_type: Type[BaseModel] = Dict,
+        output_type: Type[BaseModel] = Dict,
         *work_args: Any,
         **work_kwargs: Any,
     ) -> None:
@@ -438,6 +504,7 @@ def __init__(
             timeout_batching=timeout_batching,
             cache_calls=True,
             parallel=True,
+            work_name=self._work_cls.__name__,
         )
         for _ in range(min_replicas):
             work = self.create_work()
@@ -574,5 +641,8 @@ def autoscale(self) -> None:
         self._last_autoscale = time.time()
 
     def configure_layout(self):
-        tabs = [{"name": "Swagger", "content": self.load_balancer.url}]
+        tabs = [
+            {"name": "Endpoint Info", "content": f"{self.load_balancer}/endpoint-info"},
+            {"name": "Swagger", "content": self.load_balancer.url},
+        ]
         return tabs

tests/tests_app/components/test_auto_scaler.py → tests/tests_app/components/serve/test_auto_scaler.py

@@ -1,10 +1,11 @@
 import time
+from unittest import mock
 from unittest.mock import patch
 
 import pytest
 
 from lightning_app import CloudCompute, LightningWork
-from lightning_app.components import AutoScaler
+from lightning_app.components import AutoScaler, Text
 
 
 class EmptyWork(LightningWork):
@@ -32,8 +33,8 @@ def test_num_replicas_after_init():
 
 
 @patch("uvicorn.run")
-@patch("lightning_app.components.auto_scaler._LoadBalancer.url")
-@patch("lightning_app.components.auto_scaler.AutoScaler.num_pending_requests")
+@patch("lightning_app.components.serve.auto_scaler._LoadBalancer.url")
+@patch("lightning_app.components.serve.auto_scaler.AutoScaler.num_pending_requests")
 def test_num_replicas_not_above_max_replicas(*_):
     """Test self.num_replicas doesn't exceed max_replicas."""
     max_replicas = 6
@@ -52,8 +53,8 @@ def test_num_replicas_not_above_max_replicas(*_):
 
 
 @patch("uvicorn.run")
-@patch("lightning_app.components.auto_scaler._LoadBalancer.url")
-@patch("lightning_app.components.auto_scaler.AutoScaler.num_pending_requests")
+@patch("lightning_app.components.serve.auto_scaler._LoadBalancer.url")
+@patch("lightning_app.components.serve.auto_scaler.AutoScaler.num_pending_requests")
 def test_num_replicas_not_belo_min_replicas(*_):
     """Test self.num_replicas doesn't exceed max_replicas."""
     min_replicas = 1
@@ -98,3 +99,17 @@ def test_create_work_cloud_compute_cloned():
     auto_scaler = AutoScaler(EmptyWork, cloud_compute=cloud_compute)
     _ = auto_scaler.create_work()
     assert auto_scaler._work_kwargs["cloud_compute"] is not cloud_compute
+
+
+fastapi_mock = mock.MagicMock()
+mocked_fastapi_creater = mock.MagicMock(return_value=fastapi_mock)
+
+
+@patch("lightning_app.components.serve.auto_scaler._create_fastapi", mocked_fastapi_creater)
+@patch("lightning_app.components.serve.auto_scaler.uvicorn.run", mock.MagicMock())
+def test_API_ACCESS_ENDPOINT_creation():
+    auto_scaler = AutoScaler(EmptyWork, input_type=Text, output_type=Text)
+    assert auto_scaler.load_balancer._work_name == "EmptyWork"
+
+    auto_scaler.load_balancer.run()
+    fastapi_mock.mount.assert_called_once_with("/endpoint-info", mock.ANY, name="static")