build from a complete Singularity file instead of a docker image

Singularity

 BootStrap: docker
-From: registry-gitlab.pasteur.fr/tru/docker-miniconda3-jupyter:main
+From: continuumio/miniconda3
 
+%post
+# update conda and the OS
+conda update conda && \
+conda upgrade --all -y && \
+apt-get update && \
+DEBIAN_FRONTEND=noninteractive apt-get -y upgrade && \
+DEBIAN_FRONTEND=noninteractive apt-get -y autoremove && \
+DEBIAN_FRONTEND=noninteractive apt-get -y clean autoclean
+
+conda install ipykernel jupyterlab
+# download the yml file
+# curl  https://gitlab.pasteur.fr/tru/conda-container-howto/-/raw/main/pythonnet.yml > pythonnet.yml
+# conda env create --file pythonnet.yml

Singularity_from_docker

+BootStrap: docker
+From: registry-gitlab.pasteur.fr/tru/docker-miniconda3-jupyter:main
+