Debian Question posted in
The oficial documentation can be found here.

Evaluate bash expression in Dockerfile – Debian

I’m trying read application version from a file VERSION such that echo -n 1.0.0 > VERSION, and store the version number in an environment variable, lets say, VERSION. My Dockerfile

FROM debian
WORKDIR /app
COPY VERSION .
ENV VERSION $(cat VERSION)
# I'd like to use the version number in later steps like
RUN apt update && apt install -y curl
RUN curl path/to/executable-${VERSION}

env | grep VERSION returns:

VERSION=$(cat VERSION)

I want

VERSION=1.0.0
Tags:

2

Answers


  1. 0

    You can provide the version number as a build argument

    FROM debian
ARG VERSION
WORKDIR /app
ENV VERSION=$VERSION
# I'd like to use the version number in later steps like
RUN apt update && apt install -y curl
RUN curl path/to/executable-${VERSION}

    Then you can build it with:

    docker build --build-arg $VERSION .
    Login or Signup to reply.
  2. 0

    ENV does not interpolate variables.

    How about this:

    FROM debian
WORKDIR /app
COPY VERSION version-file
RUN echo "export VERSION=$(cat version-file)" >> /root/.bashrc
RUN apt update && apt install -y curl
RUN curl path/to/executable-${VERSION}

    This uses a RUN step to add an export command to .bashrc file. the export command adds the VERSION env var.

    Login or Signup to reply.
Please signup or login to give your own answer.

Back To Top
Search