Added 38 and created build helper script

Author: elliottmurray

docker/README.md

@@ -1,28 +1,37 @@
 # Introduction
+
 This is for contributors who want to make changes and test for all different versions of python currently supported. If you don't want to set up and install all the different python versions locally (and there are some difficulties with that) you can just run them in docker using containers.
 
 # Setup
+
 To build a container say for python 3.6 change to the root directory of the project and run
 
 ```bash
-docker build -t pact:python36 -f docker/py36.Dockerfile .
+docker build -t pactfoundation:python36 -f docker/py36.Dockerfile .
 ```
 
 And then to run you will need:
 
 ```bash
-docker run  -it -v `pwd`:/home pact:python36
+docker run  -it -v `pwd`:/home pactfoundation:python36
 ```
 
 If you need to debug you can change the command to:
 
 ```bash
-docker run  -it -v `pwd`:/home pact:python36 sh
+docker run  -it -v `pwd`:/home pactfoundation:python36 sh
 ```
 
 This will open a container with a prompt. From the /home location in the container you can run
-```
+
+```bash
 tox -e py36
 ```
 
-In all the above if you need to run a different version change py36/python36 where appropriate.
+In all the above if you need to run a different version change py36/python36 where appropriate. Or you can run the convenience script to build:
+
+```bash
+docker/build.sh 38
+```
+
+where 38 is the python environment version (3.8 in this case)

docker/build.sh

@@ -0,0 +1,14 @@
+#!/bin/sh
+set -eo pipefail
+
+if [ $# -ne 1 ]; then
+    echo "$0: usage: build.sh 27|36|37|38"
+    exit 1
+fi
+DOCKER_ENV=$1
+echo "Building env ${DOCKER_ENV}"
+
+DOCKER_IMAGE="pactfoundation:python${DOCKER_ENV}"
+DOCKER_FILE="docker/py${DOCKER_ENV}.Dockerfile"
+
+docker build -t $DOCKER_IMAGE -f $DOCKER_FILE .

docker/py38.Dockerfile

@@ -0,0 +1,12 @@
+FROM python:3.8.2-alpine3.11
+
+WORKDIR /home
+
+COPY requirements_dev.txt .
+
+RUN apk add gcc py-pip python-dev libffi-dev openssl-dev gcc libc-dev make
+
+RUN python -m pip install psutil subprocess32
+RUN pip install -r requirements_dev.txt
+
+CMD tox -e py38