Docker Deep Dive: Build Arguments

Build Arguments

Build Arguments allows to set build(image build) time variables.

$ mkdir args && cd args
/args$ git clone https://github.com/linuxacademy/content-weather-app.git src

$ cat  Dockerfile
FROM node
LABEL org.label-schema.version=v1.1
ARG SRC_DIR=/var/node   # default value /var/node

RUN mkdir -p $SRC_DIR
ADD src/ $SRC_DIR
WORKDIR $SRC_DIR
RUN npm install
EXPOSE 3000
CMD ./bin/www

args$ docker image build -t linuxacademy/weather-app:v3 --build-arg SRC_DIR=/var/code .
/args$ docker image inspect linuxacademy/weather-app:v3 | jq '.[].Config.WorkingDir'
"/var/code"

/args$ docker container run -d --name weather-app3 -p 8085:3000 linuxacademy/weather-app:v3
cb30d93dca2e6d90c21cf7fc1df623aa3b9be6f90fbed3cc3eb15c5a2a47d725

/args$ curl localhost:8085