Add a command hook to cleanup built images

[andytson-inviqa]

Replacing potential for discrepancy of deleting images based on matching hardcoding

[kierenevans]

Okay to include #515 additions?

[andytson-inviqa]

can you tell me why they wouldn't be covered by this? (maybe in slack as it'll be a bit of discussion)

[kierenevans]

Though it might do already actually!

Sorry for the build failure, trying to replace jenkins workers and had to cancel it

[kierenevans]

Testing this locally with ./build && ./test php static, I'm left with a 922MB image:

docker image ls | head -n30
REPOSITORY                            TAG                        IMAGE ID       CREATED         SIZE
<none>                                <none>                     49581cfebaeb   2 minutes ago   922MB

Seems to be due to the multi-stage build for php-fpm from console:

■ > docker-compose build php-fpm
Building php-fpm
Step 1/13 : FROM ci-php-sample-static:b1908f9e057628fc039b085c6ee94d9b659a5dfb-console as console
 ---> 91b3f0326547
Step 2/13 : RUN if [ -d /app/tools/assets/ ]; then rm -rf /app/tools/assets/; fi
 ---> Running in aad57c2336b5
Removing intermediate container aad57c2336b5
 ---> 442cfdabf896
Step 3/13 : RUN if [ -d /app/node_modules/ ]; then rm -rf /app/node_modules/; fi
 ---> Running in 3cd1e964ed86
Removing intermediate container 3cd1e964ed86
 ---> 49581cfebaeb

Step 4/13 : FROM my127/php:8.0-fpm-buster
 ---> af838a7410dc
Step 5/13 : WORKDIR /app
 ---> Running in 18b4e8e15196
Removing intermediate container 18b4e8e15196
 ---> e07650a89137

[andytson-inviqa]

that's why I'm thinking docker image prune in CI, either here or a regular cron. Can also alternatively label the image to delete it by filter, but would need to remember that practice for any other multi-stage build (which may not even be FROM a project's image)