build: use a single Dockerfile, providing args for the Python version

docker/py310.Dockerfile → docker/Dockerfile

@@ -1,4 +1,6 @@
-FROM python:3.10-alpine3.17
+ARG PY
+ARG ALPINE=3.17
+FROM python:${PY}-alpine${ALPINE}
 
 ENV PIP_ROOT_USER_ACTION=ignore
 
@@ -13,4 +15,7 @@ RUN apk update \
     && pip install --progress-bar=off --upgrade psutil \
     && pip install --progress-bar=off --use-pep517 -r requirements_dev.txt
 
-CMD ["tox", "-e", "py310-{test,install}"]
+# We can't do ENV manipulation to remove the . for tox, so need another var
+ARG TOXPY
+ENV TOXPY="${TOXPY}"
+CMD ["sh", "-c", "tox -e py${TOXPY}-{test,install}"]

docker/README.md

@@ -7,23 +7,36 @@ that) you can just run them in docker using containers.
 
 # Setup
 
-To build a container say for Python 3.11 change to the root directory of the
+To build a container say for Python 3.11, change to the root directory of the
 project and run:
 
 ```bash
-docker build -t pactfoundation:python311 -f docker/py311.Dockerfile .
+(export PY=3.11 && docker build --build-arg PY="$PY" --build-arg TOXPY="$(sed 's/\.//' <<< "$PY")" -t pactfoundation:python${PY} -f docker/Dockerfile .)
 ```
 
-To then run the tests and exit, you will need:
+This uses an Alpine based image (currently 3.17), which is available as of
+2023-04 for Python versions 3.7 - 3.11.
+
+Note: To run tox, the Python version without the '.' is required, i.e. '311'
+instead of '3.11', so some manipulation with `sed` is used to remove the '.'
+
+To build for Python versions which require a different Alpine image, such as if
+trying to build against Python 3.6, an extra `ALPINE` arg can be provided:
+
+```bash
+(export PY=3.6 && docker build --build-arg PY="$PY" --build-arg TOXPY="$(sed 's/\.//' <<< "$PY")" --build-arg ALPINE=3.15 -t pactfoundation:python${PY} -f docker/Dockerfile .)
+```
+
+To then run the tests and exit:
 
 ```bash
-docker run -it --rm -v "$(pwd)":/home pactfoundation:python311
+docker run -it --rm -v "$(pwd)":/home pactfoundation:python3.11
 ```
 
 If you need to debug you can change the command to:
 
 ```bash
-docker run -it --rm -v "$(pwd)":/home pactfoundation:python311 sh
+docker run -it --rm -v "$(pwd)":/home pactfoundation:python3.11 sh
 ```
 
 This will open a container with a prompt. From the `/home` location in the
@@ -34,11 +47,11 @@ tox -e py311-{test,install}
 ```
 
 In all the above if you need to run a different version change
-`py311`/`python311` where appropriate.  Or you can run the convenience script
+`py311`/`python3.11` where appropriate.  Or you can run the convenience script
 to build:
 
 ```bash
-docker/build.sh 311
+docker/build.sh 3.11
 ```
 
-where `311` is the python environment version (3.11 in this case).
+where `3.11` is the python environment version.

docker/build.sh

@@ -1,15 +1,28 @@
 #!/bin/sh
 
-set -eo pipefail
+set -euo pipefail
 
-if [ $# -ne 1 ]; then
-    echo "$0: usage: build.sh 37|38|39|310|311"
+if [ $# -lt 1 ]; then
+    echo "Usage: $0 PYTHON_VERSION [ALPINE_VERSION]"
+    echo
+    echo "Example:"
+    echo "$0 3.11       Build using Python 3.11, default Alpine"
+    echo "$0 3.6 3.16   Build using Python 3.6, Alpine 3.15"
     exit 1
 fi
-DOCKER_ENV=$1
-echo "Building env ${DOCKER_ENV}"
 
-DOCKER_IMAGE="pactfoundation:python${DOCKER_ENV}"
-DOCKER_FILE="docker/py${DOCKER_ENV}.Dockerfile"
+PY=$1
+ALPINE=${2:-3.17}
+echo "Building env for Python: ${PY}, Alpine: ${ALPINE}"
 
-docker build -t "$DOCKER_IMAGE" -f "$DOCKER_FILE" .
+DOCKER_IMAGE="pactfoundation:python${PY}"
+DOCKER_FILE="docker/Dockerfile"
+
+docker build \
+    --build-arg PY="$PY" \
+    --build-arg TOXPY="$(sed 's/\.//' <<< "$PY")" \
+    --build-arg ALPINE="${ALPINE}" \
+    -t "$DOCKER_IMAGE" -f "$DOCKER_FILE" .
+
+echo
+echo "Image successfully built and tagged as: ${DOCKER_IMAGE}"