Can we pass ENV variables through cmd line while building a docker image through dockerfile?

Question

I am working on a task that involves building a docker image with centOs as its base using a Dockerfile . One of the steps inside the docke

Answer 1

Containers can be built using build arguments (in Docker 1.9+) which work like environment variables.

Here is the method:

FROM php:7.0-fpm
ARG APP_ENV=local
ENV APP_ENV ${APP_ENV}
RUN cd /usr/local/etc/php && ln -sf php.ini-${APP_ENV} php.ini

and then build a production container:

docker build --build-arg APP_ENV=prod .

For your particular problem:

FROM debian
ENV http_proxy ${http_proxy}

and then run:

docker build --build-arg http_proxy=10.11.24.31 .

Note that if you build your containers with docker-compose, you can specify these build-args in the docker-compose.yml file, but not on the command-line. However, you can use variable substitution in the docker-compose.yml file, which uses environment variables.