docker - using python image, add the non-free Debian repo?

Question

Im using a python image in docker and have added some dependencies as per the below:

RUN apt-get update -y \
    && apt-get install -y apt-utils libsasl2-dev python3-dev libldap2-dev libssl-dev libsnmp-dev snmp-mibs-downloader

I'm getting an error

E: Package 'snmp-mibs-downloader' has no installation candidate

Which after searching is because I need a non-free repo adding as per: http://installion.co.uk/debian/wheezy/non-free/s/snmp-mibs-downloader/install/index.html

I believe I need to edit /etc/apt/sources.list and add the below:

deb http://http.us.debian.org/debian jessie main contrib non-free
deb http://security.debian.org jessie/updates main contrib non-free

but how do I do that via a docker file?

Answer 1

While this is the right command,

sed -i -e's/ main/ main contrib non-free/g' /etc/apt/sources.list

If you're going to do this you should do this as part of the rest of your first-image,

RUN \
  sed -i -e's/ main/ main contrib non-free/g' /etc/apt/sources.list \
  && apt-get -q update                                              \
  && apt-get -qy dist-upgrade                                       \
  && apt-get install -qy foobar                                     \
  && foobar whatever                                                \
  && apt-get -qy --purge remove foobar                              \
  && apt-get clean                                                  \
  && rm -rf /var/lib/apt/lists

The above shows this command in the full flow with the rest of the apt stuff.

Answer 2

The same way you would do to add the non-free component to your sources.list. Edit the /etc/apt/sources.list file in your Dockerfile and replace the line that looks like:

deb http://http.us.debian.org/debian jessie main contrib

by

deb http://http.us.debian.org/debian jessie main contrib non-free

You can do that in the Dockerfile with a command like

sed -i "s#deb http://http.us.debian.org/debian jessie main contrib non-free#deb http://http.us.debian.org/debian jessie main contrib non-free#g" /etc/apt/sources.list

And same for security.debian.org.