BaseEvalutionFunctionLayer

Base docker image for evaluation functions coded in python. This layer cannot function alone, it needs to be extended in a specific way by the evaluation function it supports.

This layer implements the behaviour common to all evaluation functions:

• Request and response schema validation
• Unit testing setup
• Function commands:
  • eval: calls the evaluation function in the user-defined evaluation.py file.
  • preview: calls the preview function in the user-defined preview.py file.
  • healthcheck: runs all unittests for schema testing as well as user-defined tests in evaluation_tests.py.
  • docs: returns the docs.md user-defined file.

Note: user-defined files are those provided by the evaluation function code meant to extend this layer

Behaviour and Usage

Commands as passed in 'command' header from each request. By default (if no header is present), the function will run the eval command.

Requirements from the superseding layer

This function makes references to files and functions which don't exist yet in this layer - those need to be provided by the superseding layer. They're shown here in the way a dockerfile might be extending it.

FROM ###THIS IMAGE###

WORKDIR /app

# Install requirements if your evaluation function needs them
COPY requirements.txt .
RUN pip3 install -r requirements.txt

# Copy the evaluation and testing scripts
COPY evaluation.py ./app/
COPY evaluation_tests.py ./app/

# Copy Documentation
COPY docs.md ./app/

# Set permissions so files and directories can be accessed on AWS
RUN chmod 644 $(find . -type f)
RUN chmod 755 $(find . -type d)

# The entrypoint for AWS is to invoke the handler function within the app package
CMD [ "/app/app.handler" ]

Operating Container Structure

Since this is only just a base layer for eval functions, the repo's file structure won't match the file structure inside the built image, which can get confusing at times. This is what the /app/ directory (where all our data is contained) will look like for an operational function:

|____requirements.txt
|____base_requirements.txt
|____app
   |______init__.py
   |____tests
   |  |______init__.py
   |  |____requests.py
   |  |____responses.py
   |  |____handling.py
   |  |____commands.py
   |  |____docs.py
   |  |____parse.py
   |____tools
   |  |______init__.py
   |  |____commands.py
   |  |____validate.py
   |  |____docs.py
   |  |____parse.py
   |  |____healthcheck.py
   |  |____utils.py
   |____docs.md
   |____handler.py
   |____evaluation_tests.py
   |____evaluation.py

Dev Notes

Can run the following command to look around the container of a running function

docker exec -it eval-function bash

From a container which exposes port 8080 to the real port 9000, requests can be made to the function using the url:

http://localhost:9000/2015-03-31/functions/function/invocations