CI/CD package is different from local package [jessie/stretch inconsistency] - docker

Question

When I run docker on local machine with following Dockerfile:
FROM python:3
WORKDIR /app
COPY . /app
RUN apt-get update && apt-get install -y libhunspell-1.3-0
RUN pip install -r requirements.txt
EXPOSE 9876
CMD ["python","flask_compose.py"]
It got libhunspell from following repository (jessie):
Get:1 http://security.debian.org jessie/updates InRelease [94.4 kB]
Ign http://deb.debian.org jessie InRelease
Get:2 http://deb.debian.org jessie-updates InRelease [145 kB]
Get:3 http://security.debian.org jessie/updates/main amd64 Packages [623 kB]
Get:4 http://deb.debian.org jessie Release.gpg [2434 B]
Get:5 http://deb.debian.org jessie Release [148 kB]
Get:6 http://deb.debian.org jessie-updates/main amd64 Packages [23.0 kB]
Get:7 http://deb.debian.org jessie/main amd64 Packages [9064 kB]
And everything is fine (image build and run successfully).
Unfortunately, when I run docker on gitlab repository with the same Dockerfile it calls update apt-get from another repository (stretch):
Ign:1 http://deb.debian.org/debian stretch InRelease
Get:2 http://security.debian.org/debian-security stretch/updates InRelease [94.3 kB]
Get:3 http://deb.debian.org/debian stretch-updates InRelease [91.0 kB]
Get:4 http://deb.debian.org/debian stretch Release [118 kB]
Get:5 http://deb.debian.org/debian stretch Release.gpg [2434 B]
Get:6 http://security.debian.org/debian-security stretch/updates/main amd64 Packages [440 kB]
Get:7 http://deb.debian.org/debian stretch-updates/main amd64 Packages [12.1 kB]
Get:8 http://deb.debian.org/debian stretch/main amd64 Packages [9530 kB]
Due to this inconsistency gitlab CI/CD throws following exception:
E: Unable to locate package libhunspell-1.3-0
E: Couldn't find any package by glob 'libhunspell-1.3-0'
E: Couldn't find any package by regex 'libhunspell-1.3-0'
The command '/bin/sh -c apt-get install -y libhunspell-1.3-0' returned a non-zero code: 100
ERROR: Job failed: exit code 100
Does anyone knows how change my Dockerfile that local and gitlab uses the same package repository?

Answer 1

There current tag for python:3 points to a Debian stretch based image. To update your local environment, run a docker pull python:3 or run your build with the --pull option.
You can also select a more specific tag to force your desired base image used by python. See the docker hub page for python to see all the possible tags, e.g. python:3-jessie.

Answer 2

From gitlab official forum I found a solution which fixed my problem.
1) define a setup.sh file and following command:
echo "deb http://pkg.adfinis-sygroup.ch/debian/ jessie main non-free contrib" > /etc/apt/sources.list
echo "deb http://security.debian.org/ jessie/updates main" >> /etc/apt/sources.list
echo "deb http://pkg.adfinis-sygroup.ch/debian/ jessie-updates main contrib non-free" >> /etc/apt/sources.list
apt-get update
apt-get install --no-install-recommends -y libhunspell-1.3-0
2) In Dockerfile add following commands:
From python:3
ADD setup.sh /opt/
RUN /bin/bash /opt/setup.sh
PS: Although my hack works very fine, I prefer #BMitch solution.
--------------------------------------------------------------------------------------------------------
By extending #Bmitch solution I decrease image size from ~600 to ~150 with following Dockerfile:
FROM python:3-slim-jessie
WORKDIR .
# hunspell deps
RUN apt-get update && apt-get install --no-install-recommends -y libtool libc6-dev gcc g++ build-essential libhunspell-1.3-0
COPY requirements.txt requirements.txt
RUN pip install -r requirements.txt
COPY . .
CMD ["python","flask_compose.py"]