Symfony + RoadRunner + build-time cache volume Dockerfile

Dockerfile

# syntax=docker/dockerfile:experimental
FROM alpine:3.11 AS runtime
WORKDIR /app
RUN addgroup -g 82 -S www-data && \
    adduser -u 82 -H -D -S -G www-data www-data && \
    apk add --update --no-cache \
        php7 \
        php7-ctype \
        php7-dom \
        php7-iconv \
        php7-intl \
        php7-json \
        php7-mbstring \
        php7-opcache \
        php7-xml \
        tini

FROM runtime AS installer
WORKDIR /app
RUN apk add --update --no-cache \
        php7-curl \
        php7-openssl \
        php7-phar \
        php7-zip
COPY --from=composer:1.9 /usr/bin/composer /usr/bin/composer
COPY . /app/
RUN --mount=type=cache,target=/composer COMPOSER_HOME=/composer composer install --classmap-authoritative --no-dev --no-interaction --no-scripts --no-suggest --prefer-dist && \
    vendor/bin/rr get-binary --location=vendor/bin --no-interaction && \
    bin/console cache:warmup

FROM runtime
EXPOSE 80
WORKDIR /app
# these are layered on purpose
COPY --from=installer /app/vendor /app/vendor
COPY --from=installer /app/public /app/public
COPY --from=installer /app/src /app/src
COPY --from=installer /app/templates /app/templates
COPY --from=installer /app/config /app/config
COPY --from=installer /app/.rr.yaml /app/.rr.yaml
COPY --from=installer /app/bin /app/bin
COPY --from=installer /app/var /app/var
ENTRYPOINT ["/sbin/tini", "--"]
CMD ["/app/vendor/bin/rr", "serve", "-v", "-d"]