Create debian templates for the python 3 flask templates.

The current python3-flask templates use the Alpine base python image.
Precompiled wheels for many important python libraries are not available
for Alpine, but are easily available for Debian. Using Debian makes it
much simpler and easier to use python packages like Numpy or Pillow.

Updated existing Alpine Docker files to include comments.
The template yaml file for the python-http-debian was modified to remove
unneeded libraries.

Both docker files were changed to force python 3.7. Gevent 1.4 is
incompatible with Python 3.8, and the rest of the docker files use
python 3.7.

This has been tested with a bare bones basic function and builds,
runs, and executes properly.

Change listening address for WSGI server.

Update the listening address for the WSGI server to use 0.0.0.0
instead of ''. This should resolve errors about Address family
not supported by protocol (Python OSError Errno 97.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>
Signed-off-by: Jeff Lowrey <jefferson.lowrey@mantech.com>

Author: Jeff Lowrey

template/python3-flask-debian/Dockerfile

@@ -0,0 +1,56 @@
+FROM openfaas/of-watchdog:0.7.2 as watchdog
+FROM python:3.7-slim-buster
+
+COPY --from=watchdog /fwatchdog /usr/bin/fwatchdog
+RUN chmod +x /usr/bin/fwatchdog
+
+ARG ADDITIONAL_PACKAGE
+# Alternatively use ADD https:// (which will not be cached by Docker builder)
+
+RUN apt-get -qy update && apt-get -qy install gcc make ${ADDITIONAL_PACKAGE}
+
+# Add non root user
+RUN addgroup --system app && adduser app --system --ingroup app
+RUN chown app /home/app
+
+USER app
+
+ENV PATH=$PATH:/home/app/.local/bin
+
+WORKDIR /home/app/
+
+COPY index.py           .
+COPY requirements.txt   .
+
+USER root
+RUN pip install -r requirements.txt
+
+#build function directory and install user specified componenets.
+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/
+
+#install function code
+USER root
+
+COPY function   function
+RUN chown -R app:app ./
+
+#configure WSGI server and healthcheck
+USER app
+
+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-flask-debian/function/__init__.py

@@ -0,0 +1,7 @@
+def handle(req):
+    """handle a request to the function
+    Args:
+        req (str): request body
+    """
+
+    return req

template/python3-flask-debian/function/handler.py

@@ -0,0 +1,32 @@
+# Copyright (c) Alex Ellis 2017. All rights reserved.
+# Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+from flask import Flask, request
+from function import handler
+#from gevent.wsgi import WSGIServer
+from gevent.pywsgi import WSGIServer
+
+app = Flask(__name__)
+
+@app.before_request
+def fix_transfer_encoding():
+    """
+    Sets the "wsgi.input_terminated" environment flag, thus enabling
+    Werkzeug to pass chunked requests as streams.  The gunicorn server
+    should set this, but it's not yet been implemented.
+    """
+
+    transfer_encoding = request.headers.get("Transfer-Encoding", None)
+    if transfer_encoding == u"chunked":
+        request.environ["wsgi.input_terminated"] = True
+
+@app.route("/", defaults={"path": ""}, methods=["POST", "GET"])
+@app.route("/<path:path>", methods=["POST", "GET"])
+def main_route(path):
+    ret = handler.handle(request.get_data())
+    return ret
+
+if __name__ == '__main__':
+
+    http_server = WSGIServer(('0.0.0.0', 5000), app)
+    http_server.serve_forever()

template/python3-flask-debian/function/requirements.txt

@@ -0,0 +1,3 @@
+flask
+gevent
+

template/python3-flask-debian/index.py

@@ -0,0 +1,2 @@
+language: python3-flask-debian
+fprocess: python index.py

template/python3-flask-debian/requirements.txt

@@ -5,6 +5,8 @@ COPY --from=watchdog /fwatchdog /usr/bin/fwatchdog
 RUN chmod +x /usr/bin/fwatchdog
 
 ARG ADDITIONAL_PACKAGE
+# Alternatively use ADD https:// (which will not be cached by Docker builder)
+
 RUN apk --no-cache add musl-dev gcc make ${ADDITIONAL_PACKAGE}
 
 # Add non root user
@@ -19,8 +21,11 @@ WORKDIR /home/app/
 
 COPY index.py           .
 COPY requirements.txt   .
+
 USER root
 RUN pip install -r requirements.txt
+
+#build function directory and install user specified componenets.
 USER app
 
 RUN mkdir -p function
@@ -31,9 +36,13 @@ RUN pip install --user -r requirements.txt
 
 WORKDIR /home/app/
 
+#install function code
 USER root
+
 COPY function   function
 RUN chown -R app:app ./
+
+#configure WSGI server and healthcheck
 USER app
 
 ENV fprocess="python index.py"

template/python3-flask-debian/template.yml

@@ -0,0 +1,49 @@
+FROM openfaas/of-watchdog:0.7.2 as watchdog
+FROM python:3.7-slim-buster
+
+COPY --from=watchdog /fwatchdog /usr/bin/fwatchdog
+RUN chmod +x /usr/bin/fwatchdog
+
+ARG ADDITIONAL_PACKAGE
+# Alternatively use ADD https:// (which will not be cached by Docker builder)
+
+RUN apt-get -qy update && apt-get -qy install ${ADDITIONAL_PACKAGE}
+
+# Add non root user
+RUN addgroup --system app && adduser app --system --ingroup app
+RUN chown app /home/app
+
+USER app
+
+ENV PATH=$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-flask/Dockerfile

@@ -0,0 +1,5 @@
+def handle(event, context):
+    return {
+        "statusCode": 200,
+        "body": "Hello from OpenFaaS!"
+    }