Set values on image build for a Docker container -

let's logged in reynierpm in fedora , build docker image dockerfile. image contain lamp environment. have apache virtual host(vh) default file looks follow:

<virtualhost *:80>     #servername www.example.com      serveradmin webmaster@localhost     documentroot /var/www      <directory /var/www>         allowoverride         require granted     </directory>      errorlog /dev/stdout     customlog /dev/stdout combined </virtualhost> 

as part of built process file copied proper location on image.

can logged in username host , set dynamically vh? @ end following result:

<virtualhost *:80>     servername reynierpm.dev      serveradmin webmaster@localhost     documentroot /var/www      <directory /var/www>         allowoverride         require granted     </directory>      errorlog /dev/stdout     customlog /dev/stdout combined </virtualhost> 

i know can value current user using $(whoami) bash how can insert/set vh file on docker build?

this content of dockerfile:

from ubuntu:14.04.5 maintainer me <myemail@gmail.com> arg user_name=unknown volume ["/var/www"]  run apt-get update && \     debian_frontend=noninteractive \     apt-get install -y software-properties-common && \     apt-get update && \     apt-get install -y \       apache2 \       php5 \       php5-cli \       libapache2-mod-php5 \       php5-gd \       php5-json \       php5-mcrypt \       php5-mysql \       php5-xdebug \       php5-curl \       php5-memcached \       php5-mongo \       zend-framework \       mc \       nano  # copy default virtual host file. copy /config/apache2_vhost/apache_default /etc/apache2/sites-available/000-default.conf copy run /usr/local/bin/run run chmod +x /usr/local/bin/run run a2enmod rewrite  expose 80 expose 9001  cmd ["/usr/local/bin/run"] 

update: build fails while try use args

following @elton suggestion added line run file:

sed -i "s/#servername www.example.com/$user_name.dev/g" /etc/apache2/sites-available/000-default.conf 

and try build image as:

docker build --build-arg user_name=$(whoami) -t dev-php55 . 

but failing following message:

one or more build-args [user_name] not consumed, failing build.

what's wrong?

if want value fixed in image, best option use build argument, , text substitution in dockerfile:

from ubuntu                                                                                                                                           arg user_name=unknown                                                                                                                                 run echo built by: $user_name > /builder.txt 

then pass whoami when build:

docker build --build-arg user_name=$(whoami) -t temp . 

the build argument overrides default in dockerfile image has real builder's username:

docker run temp cat /builder.txt                                                                                                                    built by: ubuntu  

edit: build arguments available environment variables during build process. neither variable or value present in final built image. can make use of argument value in build instructions run.