Enable Buildkit

For docker build command

We need to define this variable : DOCKER_BUILDKIT=1.
At each execution :
DOCKER_BUILDKIT=1 docker build -t fooTag .

Or we could also export it as an environment variable :
export DOCKER_BUILDKIT=1 # or configure in daemon.json
So only that is needed now :
docker build -t fooTag .

For docker-compose build command

We need to define the variable declared for docker build :  DOCKER_BUILDKIT=1. but also another one : COMPOSE_DOCKER_CLI_BUILD=1.
At each execution :
COMPOSE_DOCKER_CLI_BUILD=1 DOCKER_BUILDKIT=1 docker-compose build

Or we could also export it as environment variables :
export DOCKER_BUILDKIT=1 # or configure in daemon.json
export COMPOSE_DOCKER_CLI_BUILD=1
So only that is needed now :
docker-compose build

In Dockerfile

We need to enable experimental feature as first line of the Dockerfile :

# syntax=docker/dockerfile:experimental

Buildkit cache

Cache features

…

Clear cache

docker builder prune --filter type=exec.cachemount