Use the new COPY --link syntax to accelerate builds

Author: mnapoli

layers/console/Dockerfile

@@ -1,3 +1,4 @@
+# syntax = docker/dockerfile:1.4
 ARG PHP_VERSION
 ARG CPU_PREFIX
 
@@ -7,23 +8,23 @@ RUN apk add composer
 
 RUN mkdir -p /opt/bref/console-runtime
 WORKDIR /opt/bref/console-runtime
-COPY composer.json composer.json
+COPY --link composer.json composer.json
 RUN composer install --ignore-platform-req=ext-posix --ignore-platform-req=ext-simplexml
 
 FROM bref/${CPU_PREFIX}php-$PHP_VERSION as console
 
 # Overwrite the "function" bootstrap file
-COPY bref/bootstrap.php /opt/bref/bootstrap.php
+COPY --link bref/bootstrap.php /opt/bref/bootstrap.php
 
-COPY --from=composer /opt/bref/console-runtime /opt/bref/console-runtime
+COPY --link --from=composer /opt/bref/console-runtime /opt/bref/console-runtime
 
 FROM alpine:3.14 as zip-console
 
 RUN apk add zip
 
 RUN mkdir -p /opt/bref
-COPY --from=console /opt/bref/bootstrap.php /opt/bref/bootstrap.php
-COPY --from=console /opt/bref/console-runtime /opt/bref/console-runtime
+COPY --link --from=console /opt/bref/bootstrap.php /opt/bref/bootstrap.php
+COPY --link --from=console /opt/bref/console-runtime /opt/bref/console-runtime
 
 WORKDIR /opt
 

layers/fpm-dev/Dockerfile

@@ -1,3 +1,4 @@
+# syntax = docker/dockerfile:1.4
 ARG CPU_PREFIX
 ARG PHP_VERSION
 
@@ -21,16 +22,16 @@ RUN if [[ $CPU_PREFIX == "arm-" ]]; then curl -A "Docker" -o /opt/bref/extension
 
 FROM bref/${CPU_PREFIX}php-${PHP_VERSION}-fpm
 
-COPY --from=build_extensions  /opt /opt
-COPY bref-entrypoint.sh /
+COPY --link --from=build_extensions /opt /opt
+COPY --link bref-entrypoint.sh /
 RUN chmod +x /bref-entrypoint.sh
 
 # Install node to run the JS app below
 RUN curl --silent --location https://rpm.nodesource.com/setup_16.x | bash -
 RUN yum install --setopt=skip_missing_names_on_install=False -y nodejs
 
 # Install the bref/local-api-gateway app in our container (avoids running 2 containers)
-COPY --from=bref/local-api-gateway /app /local-api-gateway
+COPY --link --from=bref/local-api-gateway /app /local-api-gateway
 EXPOSE 8000
 
 # Add `php/conf.dev.d` to the path where PHP looks for configuration files