How to Solve the Slow docker build Problem

  docker, question

Dockerfile is as follows:

FROM php:7.0-fpm
 RUN apt-get update && \
 apt-get install -y \
 libz-dev \
 libpq-dev \
 libjpeg-dev \
 libpng12-dev \
 libfreetype6-dev \
 libssl-dev \
 RUN docker-php-ext-install mcrypt
 RUN docker-php-ext-install mysqli \
 && docker-php-ext-install pdo_mysql
 RUN docker-php-ext-install gd

Docker source has been replaced with domestic source

The source of the installation package is outside the wall and cannot solve the problem.