Improve start-notebook.sh checks

* Only create jovyan and set perms if user does not exist
* Allow docker host mount for NB_WORK: copy skel files if useradd fails because home dir already exists

Contribution (c) Copyright IBM Corp. 2015

minimal-notebook/Dockerfile

@@ -27,7 +27,9 @@ RUN apt-get update && apt-get install -yq --no-install-recommends \
 # Configure docker environment
 ENV CONDA_DIR /opt/conda
 ENV NB_USER jovyan
-ENV WORK /home/$NB_USER/work
+ENV NB_HOME /home/$NB_USER
+ENV NB_WORK $NB_HOME/work
+ENV WORK $NB_WORK
 ENV PATH $CONDA_DIR/bin:$PATH
 
 # Install conda

minimal-notebook/start-notebook.sh

 #!/bin/bash
-set -e
 
-# Create non-root NB_USER, member of group "users"
-useradd -m -s /bin/bash -u ${NB_UID:-1000} -G users $NB_USER
+# Create non-root NB_USER if one doesn't exist
+id -u $NB_USER && user_exists=true
+if [ -z "$user_exists" ] ; then
+    useradd -m -s /bin/bash -u ${NB_UID:-1000} $NB_USER
 
-# Allow "users" group to update conda root env
-chown -R root.users $CONDA_DIR
-chmod -R g+w $CONDA_DIR
+    # Setup a work directory rooted in the NB_USER home
+    mkdir -p $WORK
+    chown -R jovyan.jovyan $NB_HOME
 
-# Setup a work directory rooted in the NB_USER home
-mkdir -p $WORK
-chown root.users $WORK
-chmod g+w $WORK
+    # Allow "jovyan" group to update conda root env
+    chown -R root.jovyan $CONDA_DIR
+    chmod g+w $CONDA_DIR
+fi
+
+# Copy skeleton files if useradd didn't do it (e.g., volume mounted dir
+# residing in /home/jovyan prevented it)
+if [ ! -d $NB_HOME/.jupyter ]; then
+    cp -r /etc/skel/. $NB_HOME
+    chown -R jovyan.jovyan $NB_HOME
+fi
 
 # Enable sudo if requested
 if [ ! -z "$GRANT_SUDO" ]; then