new python middleware

Author: gauron99

.github/workflows/invoke-all.yaml

@@ -13,6 +13,8 @@ jobs:
     outputs:
       languages: ${{ steps.prep-matrix.outputs.languages }}
       language_paths: ${{ steps.prep-matrix.outputs.language_paths }}
+    env:
+      FUNC_VERSION: 'knative-v1.18.0'
     steps:
     - name: Checkout code
       uses: actions/checkout@v4

python/hello/Procfile

@@ -1,28 +1,73 @@
-# Python 'hello' template
+# Python HTTP Function
 
-Welcome to your new Python function project! The boilerplate function
-code can be found in [`func.py`](./func.py). This function will
-simply print 'Hello, World!' if a request is received successfuly.
+## Introduction
 
-## Endpoints
+A Python HTTP function built with ASGI protocol support. The implementation 
+provides a simple HTTP endpoint that responds with "Hello World!" to incoming 
+requests.
 
-Running this function will expose three endpoints.
+The function is structured as a class-based implementation with proper lifecycle
+management, including configurable startup and shutdown hooks.
 
-  * `/` The endpoint for your function.
-  * `/health/readiness` The endpoint for a readiness health check
-  * `/health/liveness` The endpoint for a liveness health check
+## Recommended Deployment
 
-The health checks can be accessed in your browser at
-[http://localhost:8080/health/readiness]() and
-[http://localhost:8080/health/liveness]().
+> [!NOTE]
+> We recommend using the host builder.
+> This feature is currently behind a flag because its not available for all the
+> languages yet so you will need to enable it.
 
-You can use `func invoke` to send an HTTP request to the function endpoint.
+```bash
+# Enable the host builder
+export FUNC_ENABLE_HOST_BUILDER=1
+
+# Deploy your code to cluster
+# Make sure to set the builder to use it
+func deploy --builder=host
+
+# Local development and testing
+func run --builder=host --container=false
+```
+
+## Customization
+
+- This function uses the ASGI (Asynchronous Server Gateway Interface) 3.0
+specification therefore its compatible with the signature `handle(scope, receive, send)`
+
+### Lifecycle Management
+The function provides lifecycle hooks:
+- **start()**: Initialization hook called when function instances are created
+- **stop()**: Cleanup hook, ensuring graceful termination and resource cleanup
+- **alive()**: Health check exposed at `/health/liveness`
+- **ready()**: Readiness check exposed at `/health/readiness`
 
 ## Testing
 
-This function project includes a [unit test](./test_func.py). Update this
-as you add business logic to your function in order to test its behavior.
+The function includes unit tests that verify the HTTP handler behavior. 
+Tests are located in the `tests/` directory and use pytest with asyncio support.
+
+To run the tests:
 
-```console
-python test_func.py
+```bash
+# Install dependencies (if not already installed)
+pip install -e .
+
+# Run tests
+pytest
+
+# Run tests with verbose output
+pytest -v
 ```
+
+### Test Structure
+
+Tests are organized in the `tests/` directory with the current test file 
+`test_func.py` verifying that the ASGI handler returns a proper 200 OK response.
+The testing framework uses pytest with asyncio support, configured in `pyproject.toml`.
+
+### Writing New Tests
+
+To add new tests, create files named `test_*.py` in the `tests/` directory. 
+For async functions, use the `@pytest.mark.asyncio` decorator. Mock ASGI 
+components by creating mock `scope`, `receive`, and `send` functions as shown 
+in the existing test. You can also test lifecycle methods like `start()`, 
+`stop()`, `alive()`, and `ready()` by calling them directly on a function instance.

python/hello/README.md

@@ -0,0 +1 @@
+from .func import new

python/hello/app.sh

@@ -0,0 +1,72 @@
+# Function
+import logging
+
+
+def new():
+    """ New is the only method that must be implemented by a Function.
+    The instance returned can be of any name.
+    """
+    return Function()
+
+
+class Function:
+    def __init__(self):
+        """ The init method is an optional method where initialization can be
+        performed. See the start method for a startup hook which includes
+        configuration.
+        """
+
+    async def handle(self, scope, receive, send):
+        """ Handle all HTTP requests to this Function other than readiness
+        and liveness probes."""
+
+        logging.info("OK: Request Received")
+
+        # echo the request to the calling client
+        await send({
+            'type': 'http.response.start',
+            'status': 200,
+            'headers': [
+                [b'content-type', b'text/plain'],
+            ],
+        })
+        await send({
+            'type': 'http.response.body',
+            'body': 'Hello World!'.encode(),
+        })
+
+    def start(self, cfg):
+        """ start is an optional method which is called when a new Function
+        instance is started, such as when scaling up or during an update.
+        Provided is a dictionary containing all environmental configuration.
+        Args:
+            cfg (Dict[str, str]): A dictionary containing environmental config.
+                In most cases this will be a copy of os.environ, but it is
+                best practice to use this cfg dict instead of os.environ.
+        """
+        logging.info("Function starting")
+
+    def stop(self):
+        """ stop is an optional method which is called when a function is
+        stopped, such as when scaled down, updated, or manually canceled.  Stop
+        can block while performing function shutdown/cleanup operations.  The
+        process will eventually be killed if this method blocks beyond the
+        platform's configured maximum studown timeout.
+        """
+        logging.info("Function stopping")
+
+    def alive(self):
+        """ alive is an optional method for performing a deep check on your
+        Function's liveness.  If removed, the system will assume the function
+        is ready if the process is running. This is exposed by default at the
+        path /health/liveness.  The optional string return is a message.
+        """
+        return True, "Alive"
+
+    def ready(self):
+        """ ready is an optional method for performing a deep check on your
+        Function's readiness.  If removed, the system will assume the function
+        is ready if the process is running.  This is exposed by default at the
+        path /health/rediness.
+        """
+        return True, "Ready"

python/hello/func.py

@@ -0,0 +1,24 @@
+[project]
+name = "function"
+description = ""
+version = "0.1.0"
+requires-python = ">=3.9"
+readme = "README.md"
+license = "MIT"
+dependencies = [
+  "httpx",
+  "pytest",
+  "pytest-asyncio"
+]
+authors = [
+  { name="Your Name", email="you@example.com"},
+]
+
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[tool.pytest.ini_options]
+asyncio_mode = "strict"
+asyncio_default_fixture_loop_scope = "function"
+