Update the handler to match style of golang-http-template

- Created two new templates, python3-http & python3-http-armhf
- Added waitress as the production server for new templates

Signed-off-by: Kevin Turcios <kevin_turcios@outlook.com>

.gitignore

@@ -1,2 +1 @@
-*.pyc
 build

README.md

@@ -1,32 +1,158 @@
-# python-flask-template
+OpenFaaS Python Flask Templates
+=============================================
 
-Python OpenFaaS template with Flask
+The Python Flask templates make use of the incubator project [of-watchdog](https://github.com/openfaas-incubator/of-watchdog) to handle higher throughput than the [classic watchdog](https://github.com/openfaas/faas/tree/master/watchdog) due to the process being kept warm.
 
-To try this out with either Python 2.7 or Python 3.6:
-
-```bash
-faas template pull https://github.com/openfaas-incubator/python-flask-template
-faas new --list
-Languages available as templates:
+Templates available under this repository:
 - python27-flask
 - python3-flask
-```
+- python3-flask-armhf
+- python3-http*
+- python3-http-armhf*
 
-Generate a function with one of the languages:
+Notes: 
+- The templates listed with an asterik are the only ones that support additional control over the HTTP response and provide access to HTTP request details.
+- To build and deploy a function for Raspberry Pi or ARMv7 in general, use the language templates ending in *-armhf*
 
-```bash
-faas new --lang python3-flask myfunction
-mv myfunction.yml stack.yml
+## Downloading the templates
+```
+$ faas template pull https://github.com/openfaas-incubator/python-flask-template
 ```
 
-Followed by the usual flow:
+# Using the python27-flask/python3-flask templates
+Create a new function
+```
+$ faas new --lang python27-flask <fn-name>
+```
+Build, push, and deploy
+```
+$ faas up -f <fn-name>.yml
+```
+Test the new function
+```
+$ echo -n content | faas invoke <fn-name>
+```
 
+# Using the python3-http templates
+Create a new function
+```
+$ faas new --lang python3-http <fn-name>
+```
+Build, push, and deploy
+```
+$ faas up -f <fn-name>.yml
+```
+Set your OpenFaaS gateway URL. For example:
 ```
-faas build \
-  && faas deploy
-  && faas list --verbose
+$ OPENFAAS_URL=http://127.0.0.1:8080
+```
+Test the new function
+```
+$ curl -i $OPENFAAS_URL/function/<fn-name>
+```
+
+## Event and Context Data
+The function handler is passed two arguments, *event* and *context*.
+
+*event* contains data about the request, including:
+- body
+- headers
+- method
+- query
+- path
+
+*context* contains basic information about the function, including:
+- hostname
+
+## Response Bodies
+By default, flask will automatically attempt to set the correct Content-Type header for you based on the type of response. 
 
-# Wait a couple of seconds then:
+For example, returning a dict object type will automatically attach the header `Content-Type: application/json` and returning a string type will automatically attach the `Content-Type: text/html, charset=utf-8` for you.
 
-echo -n content | faas invoke myfunction
+## Example usage
+### Custom Status Codes and Response Bodies
+Successful response status code and JSON response body
+```python
+def handle(event, context):
+    return {
+        "statusCode": 200,
+        "body": {
+            "key": "value"
+        }
+    }
+```
+Successful response status code and string response body
+```python
+def handle(event, context):
+    return {
+        "statusCode": 201,
+        "body": "Object successfully created"
+    }
+```
+Failure response status code and JSON error message
+```python
+def handle(event, context):
+    return {
+        "statusCode": 400,
+        "body": {
+            "error": "Bad request"
+        }
+    }
+```
+### Custom Response Headers
+Setting custom response headers
+```python
+def handle(event, context):
+    return {
+        "statusCode": 200,
+        "body": {
+            "key": "value"
+        },
+        "headers": {
+            "Location": "https://www.example.com/"
+        }   
+    }
+```
+### Accessing Event Data
+Accessing request body
+```python
+def handle(event, context):
+    return {
+        "statusCode": 200,
+        "body": "You said: " + str(event.body)
+    }
+```
+Accessing request method
+```python
+def handle(event, context):
+    if event.method == 'GET':
+        return {
+            "statusCode": 200,
+            "body": "GET request"
+        }
+    else:
+        return {
+            "statusCode": 405,
+            "body": "Method not allowed"
+        }
+```
+Accessing request query string arguments
+```python
+def handle(event, context):
+    return {
+        "statusCode": 200,
+        "body": {
+            "name": event.query['name']
+        }
+    }
 ```
+Accessing request headers
+```python
+def handle(event, context):
+    return {
+        "statusCode": 200,
+        "body": {
+            "content-type-received": event.headers['Content-Type']
+        }
+    }
+```

template/python3-http-armhf/Dockerfile

@@ -0,0 +1,48 @@
+FROM armhf/python:3.6-alpine
+
+ARG ADDITIONAL_PACKAGE
+# Alternatively use ADD https:// (which will not be cached by Docker builder)
+RUN apk --no-cache add curl ${ADDITIONAL_PACKAGE} \
+    && echo "Pulling watchdog binary from Github." \
+    && curl -sSLf https://github.com/openfaas-incubator/of-watchdog/releases/download/0.4.6/of-watchdog-armhf > /usr/bin/fwatchdog \
+    && chmod +x /usr/bin/fwatchdog \
+    && apk del curl --no-cache
+
+# Add non root user
+RUN addgroup -S app && adduser app -S -G app
+RUN chown app /home/app
+
+USER app
+
+ENV PATH=$PATH:/home/app/.local/bin
+
+WORKDIR /home/app/
+
+COPY index.py           .
+COPY requirements.txt   .
+USER root
+RUN pip install -r requirements.txt
+USER app
+
+RUN mkdir -p function
+RUN touch ./function/__init__.py
+WORKDIR /home/app/function/
+COPY function/requirements.txt	.
+RUN pip install --user -r requirements.txt
+
+WORKDIR /home/app/
+
+USER root
+COPY function   function
+RUN chown -R app:app ./
+USER app
+
+# Set up of-watchdog for HTTP mode
+ENV fprocess="python index.py"
+ENV cgi_headers="true"
+ENV mode="http"
+ENV upstream_url="http://127.0.0.1:5000"
+
+HEALTHCHECK --interval=5s CMD [ -e /tmp/.lock ] || exit 1
+
+CMD ["fwatchdog"]

template/python3-http-armhf/function/handler.py

@@ -0,0 +1,6 @@
+def handle(event, context):
+    # TODO implement
+    return {
+        "statusCode": 200,
+        "body": "Hello from OpenFaaS!"
+    }

template/python3-http-armhf/index.py

@@ -0,0 +1,68 @@
+from flask import Flask, request, jsonify
+from waitress import serve
+import os
+
+from function import handler
+
+app = Flask(__name__)
+
+class Event:
+    def __init__(self):
+        self.body = request.get_data()
+        self.headers = request.headers
+        self.method = request.method
+        self.query = request.args
+        self.path = request.path
+
+class Context:
+    def __init__(self):
+        self.hostname = os.environ['HOSTNAME']
+
+def format_status_code(resp):
+    if 'statusCode' in resp:
+        return resp['statusCode']
+
+    return 200
+
+def format_body(resp):
+    if 'body' not in resp:
+        return ""
+    elif type(resp['body']) == dict:
+        return jsonify(resp['body'])
+    else:
+        return str(resp['body'])
+
+def format_headers(resp):
+    if 'headers' not in resp:
+        return []
+    elif type(resp['headers']) == dict:
+        headers = []
+        for key in resp['headers'].keys():
+            header_tuple = (key, resp['headers'][key])
+            headers.append(header_tuple)
+        return headers
+
+    return resp['headers']
+
+def format_response(resp):
+    if resp == None:
+        return ('', 200)
+
+    statusCode = format_status_code(resp)
+    body = format_body(resp)
+    headers = format_headers(resp)
+
+    return (body, statusCode, headers)
+
+@app.route('/', defaults={'path': ''}, methods=['GET', 'PUT', 'POST', 'PATCH', 'DELETE'])
+@app.route('/<path:path>', methods=['GET', 'PUT', 'POST', 'PATCH' 'DELETE'])
+def call_handler(path):
+    event = Event()
+    context = Context()
+    response_data = handler.handle(event, context)
+
+    resp = format_response(response_data)
+    return resp
+
+if __name__ == '__main__':
+    serve(app, host='0.0.0.0', port=5000)

template/python3-http-armhf/requirements.txt

@@ -0,0 +1,2 @@
+flask
+waitress

template/python3-http-armhf/template.yml

@@ -0,0 +1,14 @@
+language: python3-http-armhf
+fprocess: python index.py
+build_options:
+  - name: dev
+    packages: 
+      - make
+      - automake
+      - gcc
+      - g++
+      - subversion
+      - python3-dev
+      - musl-dev
+      - libffi-dev
+      - git

template/python3-http/Dockerfile

@@ -0,0 +1,48 @@
+FROM python:3.7-alpine
+
+ARG ADDITIONAL_PACKAGE
+# Alternatively use ADD https:// (which will not be cached by Docker builder)
+RUN apk --no-cache add curl ${ADDITIONAL_PACKAGE} \
+    && echo "Pulling watchdog binary from Github." \
+    && curl -sSLf https://github.com/openfaas-incubator/of-watchdog/releases/download/0.4.6/of-watchdog > /usr/bin/fwatchdog \
+    && chmod +x /usr/bin/fwatchdog \
+    && apk del curl --no-cache
+
+# Add non root user
+RUN addgroup -S app && adduser app -S -G app
+RUN chown app /home/app
+
+USER app
+
+ENV PATH=$PATH:/home/app/.local/bin
+
+WORKDIR /home/app/
+
+COPY index.py           .
+COPY requirements.txt   .
+USER root
+RUN pip install -r requirements.txt
+USER app
+
+RUN mkdir -p function
+RUN touch ./function/__init__.py
+WORKDIR /home/app/function/
+COPY function/requirements.txt	.
+RUN pip install --user -r requirements.txt
+
+WORKDIR /home/app/
+
+USER root
+COPY function   function
+RUN chown -R app:app ./
+USER app
+
+# Set up of-watchdog for HTTP mode
+ENV fprocess="python index.py"
+ENV cgi_headers="true"
+ENV mode="http"
+ENV upstream_url="http://127.0.0.1:5000"
+
+HEALTHCHECK --interval=5s CMD [ -e /tmp/.lock ] || exit 1
+
+CMD ["fwatchdog"]

template/python3-http/function/handler.py

@@ -0,0 +1,6 @@
+def handle(event, context):
+    # TODO implement
+    return {
+        "statusCode": 200,
+        "body": "Hello from OpenFaaS!"
+    }