Sample datatype for Serve Component

examples/app_server/app.py

@@ -0,0 +1,42 @@
+# !pip install torchvision pydantic
+import base64
+import io
+
+import torch
+import torchvision
+from PIL import Image
+from pydantic import BaseModel
+
+import lightning as L
+from lightning.app.components.serve import Image as InputImage
+from lightning.app.components.serve import PythonServer
+
+
+class PyTorchServer(PythonServer):
+    def setup(self):
+        self._model = torchvision.models.resnet18(pretrained=True)
+        self._device = torch.device("cuda:0" if torch.cuda.is_available() else "cpu")
+        self._model.to(self._device)
+
+    def predict(self, request):
+        image = base64.b64decode(request.image.encode("utf-8"))
+        image = Image.open(io.BytesIO(image))
+        transforms = torchvision.transforms.Compose(
+            [
+                torchvision.transforms.Resize(224),
+                torchvision.transforms.ToTensor(),
+                torchvision.transforms.Normalize([0.485, 0.456, 0.406], [0.229, 0.224, 0.225]),
+            ]
+        )
+        image = transforms(image)
+        image = image.to(self._device)
+        prediction = self._model(image.unsqueeze(0))
+        return {"prediction": prediction.argmax().item()}
+
+
+class OutputData(BaseModel):
+    prediction: int
+
+
+component = PyTorchServer(input_type=InputImage, output_type=OutputData, cloud_compute=L.CloudCompute("gpu"))
+app = L.LightningApp(component)

src/lightning/__setup__.py

@@ -35,6 +35,7 @@ def _adjust_manifest(**kwargs: Any) -> None:
         "recursive-include requirements *.txt",
         "recursive-include src/lightning/app/ui *",
         "recursive-include src/lightning/cli/*-template *",  # Add templates as build-in
+        "include src/lightning/app/components/serve/catimage.png" + os.linesep,
         # fixme: this is strange, this shall work with setup find package - include
         "prune src/lightning_app",
         "prune src/lightning_lite",

src/lightning_app/__setup__.py

@@ -50,6 +50,7 @@ def _adjust_manifest(**__: Any) -> None:
         "recursive-exclude src *.md" + os.linesep,
         "recursive-exclude requirements *.txt" + os.linesep,
         "recursive-include src/lightning_app *.md" + os.linesep,
+        "include src/lightning_app/components/serve/catimage.png" + os.linesep,
         "recursive-include requirements/app *.txt" + os.linesep,
         "recursive-include src/lightning_app/cli/*-template *" + os.linesep,  # Add templates
     ]

src/lightning_app/components/__init__.py

@@ -9,7 +9,7 @@
 from lightning_app.components.python.popen import PopenPythonScript
 from lightning_app.components.python.tracer import Code, TracerPythonScript
 from lightning_app.components.serve.gradio import ServeGradio
-from lightning_app.components.serve.python_server import PythonServer
+from lightning_app.components.serve.python_server import Image, Number, PythonServer
 from lightning_app.components.serve.serve import ModelInferenceAPI
 from lightning_app.components.serve.streamlit import ServeStreamlit
 from lightning_app.components.training import LightningTrainingComponent, PyTorchLightningScriptRunner
@@ -24,6 +24,8 @@
     "ServeStreamlit",
     "ModelInferenceAPI",
     "PythonServer",
+    "Image",
+    "Number",
     "MultiNode",
     "LiteMultiNode",
     "LightningTrainingComponent",

src/lightning_app/components/serve/__init__.py

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

src/lightning_app/components/serve/python_server.py

@@ -1,5 +1,7 @@
 import abc
-from typing import Any, Dict
+import base64
+from pathlib import Path
+from typing import Any, Dict, Optional
 
 import uvicorn
 from fastapi import FastAPI
@@ -12,6 +14,12 @@
 logger = Logger(__name__)
 
 
+def image_to_base64(image_path):
+    with open(image_path, "rb") as image_file:
+        encoded_string = base64.b64encode(image_file.read())
+    return encoded_string.decode("UTF-8")
+
+
 class _DefaultInputData(BaseModel):
     payload: str
 
@@ -20,6 +28,25 @@ class _DefaultOutputData(BaseModel):
     prediction: str
 
 
+class Image(BaseModel):
+    image: Optional[str]
+
+    @staticmethod
+    def _get_sample_data() -> Dict[Any, Any]:
+        imagepath = Path(__file__).absolute().parent / "catimage.png"
+        with open(imagepath, "rb") as image_file:
+            encoded_string = base64.b64encode(image_file.read())
+        return {"image": encoded_string.decode("UTF-8")}
+
+
+class Number(BaseModel):
+    prediction: Optional[int]
+
+    @staticmethod
+    def _get_sample_data() -> Dict[Any, Any]:
+        return {"prediction": 463}
+
+
 class PythonServer(LightningWork, abc.ABC):
     def __init__(  # type: ignore
         self,
@@ -110,6 +137,9 @@ def predict(self, request: Any) -> Any:
 
     @staticmethod
     def _get_sample_dict_from_datatype(datatype: Any) -> dict:
+        if hasattr(datatype, "_get_sample_data"):
+            return datatype._get_sample_data()
+
         datatype_props = datatype.schema()["properties"]
         out: Dict[str, Any] = {}
         for k, v in datatype_props.items():
@@ -141,7 +171,7 @@ def _attach_frontend(self, fastapi_app: FastAPI) -> None:
         url = self._future_url if self._future_url else self.url
         if not url:
             # if the url is still empty, point it to localhost
-            url = f"http://127.0.0.1{self.port}"
+            url = f"http://127.0.0.1:{self.port}"
         url = f"{url}/predict"
         datatype_parse_error = False
         try:

tests/tests_app/components/serve/test_python_server.py

@@ -1,6 +1,6 @@
 import multiprocessing as mp
 
-from lightning_app.components import PythonServer
+from lightning_app.components import Image, Number, PythonServer
 from lightning_app.utilities.network import _configure_session, find_free_network_port
 
 
@@ -29,3 +29,17 @@ def test_python_server_component():
     res = session.post(f"http://127.0.0.1:{port}/predict", json={"payload": "test"})
     process.terminate()
     assert res.json()["prediction"] == "test"
+
+
+def test_image_sample_data():
+    data = Image()._get_sample_data()
+    assert isinstance(data, dict)
+    assert "image" in data
+    assert len(data["image"]) > 100
+
+
+def test_number_sample_data():
+    data = Number()._get_sample_data()
+    assert isinstance(data, dict)
+    assert "prediction" in data
+    assert data["prediction"] == 463