CI: Update image build to latest best practices (kaniko, ...)

.gitlab-ci.yml

-stages:
-- build_image
-#- test
-
 variables:
-  DEPENDENCIES_IMAGE_NAME: "${CI_REGISTRY_IMAGE}/image:latest"
-  MYDOCKER_IMAGE_NAME: "${CI_REGISTRY_IMAGE}/mydocker-image:latest"
-  STORAGE_DRIVER: vfs # for buildah
-  REGISTRY_AUTH_FILE: /root/auth.json
+  IMAGE: "${CI_REGISTRY_IMAGE}/image:latest"
+  IMAGE_WITH_VERSION: "${CI_REGISTRY_IMAGE}/image:${CI_COMMIT_SHA}"
 
 build_image:
-  stage: build_image
-#  image: tomkukral/buildah:0.31
-  before_script:
-    - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
-#    - podman login --username "${CI_REGISTRY_USER}" --password "${CI_REGISTRY_PASSWORD}" "${CI_REGISTRY}"
+  # ref: https://docs.gitlab.com/ee/ci/docker/using_kaniko.html
+  tags:
+  - docker
+  image:
+   name: gcr.io/kaniko-project/executor:v1.23.2-debug
+   entrypoint: [""]
   script:
-    - docker build -t ${DEPENDENCIES_IMAGE_NAME} --file Dockerfile-CI .
-    - docker push ${DEPENDENCIES_IMAGE_NAME}
-#    - buildah build-using-dockerfile --format docker -t ${DEPENDENCIES_IMAGE_NAME} --file Dockerfile-CI .
-#    - buildah push --authfile ${REGISTRY_AUTH_FILE} ${DEPENDENCIES_IMAGE_NAME}
-  after_script:
-    - podman logout "${CI_REGISTRY}"
-#  only:
-#    changes:
-
-image: ${DEPENDENCIES_IMAGE_NAME}
+    - /kaniko/executor
+      --context "${CI_PROJECT_DIR}"
+      --dockerfile "${CI_PROJECT_DIR}/Dockerfile-CI"
+      --destination "${IMAGE_WITH_VERSION}"
+      --destination "${IMAGE}"
+      --cache=true
+      --single-snapshot
+      --snapshot-mode=time
+    #  --compressed-caching=false
 
 # test:
 #     stage: test

Dockerfile-CI

@@ -5,16 +5,30 @@ COPY --chown=$MAMBA_USER:$MAMBA_USER . /tmp/binder
 # Install conda packages
 RUN cd /tmp/binder && \
     micromamba install -y -n base -f environment.yml && \
-    micromamba clean --all --yes
-    
-# Install configuration files
-# After installing the packages to make sure these
-# take precedence
-RUN cp -rav /tmp/binder/install_files/* /opt/conda/
+    micromamba clean --all --yes && \
+    /usr/local/bin/_entrypoint.sh pip cache purge
 
+# Install configuration files after installing the packages to make
+# sure these take precedence
+RUN cp -rav /tmp/binder/install_files/* /opt/conda/
 RUN rm -rf /tmp/binder
 
 # Set up environment
-VOLUME /home/mambauser
+WORKDIR /home/mambauser
 ENV SHELL=/bin/bash
 ENV LANG fr_FR.UTF-8
+
+USER root
+
+# Activate the conda environment in the shell
+RUN /usr/local/bin/_entrypoint.sh mamba shell activate >> /etc/profile.d/conda.sh
+
+# Install debian packages
+RUN apt-get update && \
+    DEBIAN_FRONTEND=noninteractive apt-get install -y -q --no-install-recommends \
+        less tree \
+	&& \
+    apt-get clean && \
+    rm -rf /var/lib/apt/lists/*
+
+USER $MAMBA_USER