Added sample for inferring with ONNX models

Author: snobu

README.md

@@ -25,6 +25,7 @@ This is a collection of Python function samples on Azure Functions 2.X. For a co
 | [timer-trigger-cosmos-output-binding](v2functions/timer-trigger-cosmosdb-output-binding) | Azure Functions Timer Trigger Python Sample. The function gets blog RSS feed and store the results into CosmosDB using Cosmos DB output binding | Timer | NONE | CosmosDB |
 | [http-trigger-blob-sas-token](v2functions/http-trigger-blob-sas-token) | Azure Function HTTP Trigger Python Sample that returns a SAS token for Azure Storage for the specified container and blob name | HTTP | NONE | HTTP |
 | [http-trigger-dump-request](v2functions/http-trigger-dump-request) | Azure Function HTTP Trigger Python Sample that returns request dump info with JSON format | HTTP | NONE | HTTP |
+| [http-trigger-onnx-model](v2functions/http-trigger-onnx-model) | This function demonstrates running an inference using an ONNX model. It is triggered by an HTTP request. | HTTP | NONE | HTTP |
 | [blob-trigger-watermark-blob-out-binding](v2functions/blob-trigger-watermark-blob-out-binding) | Azure Function Python Sample that watermarks an image. This function triggers on an input blob (image) and adds a watermark by calling into the Pillow library. The resulting composite image is then written back to blob storage using a blob output binding. | Blob Storage | Blob Storage | Blob Storage |
 | [sbqueue-trigger-sbqueue-out-binding](v2functions/sbqueue-trigger-sbqueue-out-binding) | Azure Functions Service Bus Queue Trigger Python Sample. The function demonstrates reading from a Service Bus queue and placing a message into an output Service Bus queue. | Service Bus Queue | None | Service Bus Queue |
 

v2functions/http-trigger-onnx-model/__init__.py

@@ -0,0 +1,65 @@
+import logging
+import azure.functions as func
+import onnxruntime
+from PIL import Image
+import numpy as np
+import io
+
+def main(req: func.HttpRequest, context: func.Context) -> func.HttpResponse:
+    logging.info('Python HTTP trigger function processed a request.')
+
+    body = req.get_body()
+
+    try:
+        image = Image.open(io.BytesIO(body))
+    except IOError:
+        return func.HttpResponse(
+                "Bad input. Unable to cast request body to an image format.",
+                status_code=400
+        )
+
+    result = run_inference(image, context)
+
+    return func.HttpResponse(result)
+
+def run_inference(image, context):
+    # See https://github.com/onnx/models/tree/master/vision/style_transfer/fast_neural_style
+    # for implementation details
+    model_path = f'{context.function_directory}/rain_princess.onnx'
+    session = onnxruntime.InferenceSession(model_path)
+    metadata = session.get_modelmeta()
+    logging.info(f'Model metadata:\n' +
+        f'    Graph name: {metadata.graph_name}\n' +
+        f'    Model version: {metadata.version}\n' +
+        f'    Producer: {metadata.producer_name}')
+
+    # Preprocess image
+    original_image_size = image.size[0], image.size[1]
+    logging.info('Preprocessing image...')
+    # Model expects a 224x224 shape input
+    image = image.resize((224, 224), Image.ANTIALIAS)
+    x = np.array(image).astype('float32')
+    x = np.transpose(x, [2, 0, 1])
+    x = np.expand_dims(x, axis=0)
+
+    output_name = session.get_outputs()[0].name
+    input_name = session.get_inputs()[0].name
+    logging.info('Running inference on ONNX model...')
+    result = session.run([output_name], {input_name: x})[0][0]
+
+    # Postprocess image
+    result = np.clip(result, 0, 255)
+    result = result.transpose(1,2,0).astype("uint8")
+    img = Image.fromarray(result)
+    max_width  = 800
+    height = int(max_width * original_image_size[1] / original_image_size[0])
+    # Upsample and correct aspect ratio for final image
+    img = img.resize((max_width, height), Image.BICUBIC)
+    
+    # Store inferred image as in memory byte array
+    img_byte_arr = io.BytesIO()
+    # Convert composite to RGB so we can return JPEG
+    img.convert('RGB').save(img_byte_arr, format='JPEG')
+    final_image = img_byte_arr.getvalue()
+
+    return final_image

v2functions/http-trigger-onnx-model/example.png

@@ -0,0 +1,20 @@
+{
+  "scriptFile": "__init__.py",
+  "bindings": [
+    {
+      "authLevel": "function",
+      "type": "httpTrigger",
+      "direction": "in",
+      "name": "req",
+      "methods": [
+        "get",
+        "post"
+      ]
+    },
+    {
+      "type": "http",
+      "direction": "out",
+      "name": "$return"
+    }
+  ]
+}

v2functions/http-trigger-onnx-model/function.json

@@ -0,0 +1,102 @@
+# http-trigger-onnx-model (Python)
+
+| Sample | Description | Trigger | In Bindings | Out Bindings
+| ------------- | ------------- | ------------- | ----------- | ----------- |
+| `http-trigger-onnx-model`` | This function demonstrates running an inferrence against an ONNX model. | HTTP | NONE | HTTP |
+
+The style transfer model used in this function is called _Rain Princess_ and is downloaded from the [ONNX Model Zoo][3]. Artistic style transfer models mix the content of an image with the style of another image. Examples of the styles can be seen [here][4].
+
+Open Neural Network Exchange (ONNX) is an open standard format for representing machine learning models. ONNX is supported by a community of partners who have implemented it in many frameworks and tools.
+
+The ONNX Model Zoo is a collection of pre-trained, state-of-the-art models in the ONNX format contributed by community members like you. See https://github.com/onnx/models for more.
+
+You should be able to use other ONNX models in your function by rewriting the preprocess/postprocess code and wiring the expected inputs and outputs.
+
+## Sample run
+![Screenshot](example.png)
+This example is probably not going to age well. However the pun stands on its own. Shown here: [httpie][1], [imgcat][2].
+
+## Dependencies
+```
+Pillow=7.0.0
+onnxruntime==1.1.0
+numpy==1.18.1
+```
+
+## Logging includes model metadata
+
+```
+[1/19/20 8:00:25 PM] Python HTTP trigger function processed a request.
+[1/19/20 8:00:25 PM] Model metadata:
+[1/19/20 8:00:25 PM]     Graph name: torch-jit-export
+[1/19/20 8:00:25 PM]     Model version: 9223372036854775807
+[1/19/20 8:00:25 PM]     Producer: pytorch
+[1/19/20 8:00:25 PM] Preprocessing image...
+[1/19/20 8:00:25 PM] Running inference on ONNX model...
+```
+
+## Configuration
+As specified in `functions.json`, this function is triggered by an HTTP request. It expects a POST request with raw image bytes (JPEG/PNG/whatever the Pillow library can open). Output is an HTTP response with the resulting styled transferred image (JPEG encoded).
+
+```json
+{
+  "scriptFile": "__init__.py",
+  "bindings": [
+    {
+      "authLevel": "function",
+      "type": "httpTrigger",
+      "direction": "in",
+      "name": "req",
+      "methods": [
+        "post"
+      ]
+    },
+    {
+      "type": "http",
+      "direction": "out",
+      "name": "$return"
+    }
+}
+```
+
+## How to develop and publish the functions
+
+### Local development
+
+```sh
+func host start
+```
+
+### Try it out
+```bash
+# Make a POST request
+$ curl -s --data-binary @babyyoda.jpg http://localhost:7071/api/http-trigger-onnx-model -o out.jpg
+
+# Open the resulting image (on a Mac)
+# Use feh or xdg-open on Linux
+$ open out.jpg
+```
+
+### Publish the function to the cloud
+
+Publish the function to the cloud
+```sh
+FUNCTION_APP_NAME="MyFunctionApp"
+func azure functionapp publish $FUNCTION_APP_NAME --build-native-deps --no-bundler
+```
+
+Add Functions App Settings
+```sh
+FUNCTION_STORAGE_CONNECTION="*************"
+az webapp config appsettings set \
+  -n $FUNCTION_APP_NAME \
+  -g $RESOURCE_GROUP \
+  --settings \
+    MyStorageConnectionString=$FUNCTION_STORAGE_CONNECTION
+```
+
+
+[1]: https://httpie.org/
+[2]: https://iterm2.com/documentation-images.html
+[3]: https://github.com/onnx/models/tree/master/vision/style_transfer/fast_neural_style
+[4]: https://github.com/pytorch/examples/tree/master/fast_neural_style#models

v2functions/http-trigger-onnx-model/rain_princess.onnx

@@ -8,4 +8,6 @@ six==1.11.0
 # Additional packages
 requests==2.20.1
 feedparser==5.2.1
-pillow>=6.2.0
+Pillow==7.0.0
+numpy==1.18.1
+onnxruntime==1.1.0