ENH: pass DATALAD_CONTAINER_NAME inside the env and adjust PS1

DATALAD_CONTAINER_NAME is yet to be supported/set by datalad-container.
PR: datalad/datalad-container#84

But decided also to improve the PS1 altogether so we could make PS1 less
cryptic and set explicitly to point to being under singularity and also
shorten the long annex key if using old singularity

Author: yarikoptic

binds/HOME/.bashrc

@@ -3,8 +3,20 @@ if [ ! -z "$PS1" ]; then
     # Since we are using git-annex for images, SINGULARITY_NAME would
     # carry the dereferenced filename - git-annex key which is not
     # that useful to see, so we just add [SING] marker
-    if ! echo "$PS1" | grep -q SINGULARITY_NAME; then
-       export PS1="${SINGULARITY_NAME:+[SING]}$PS1"
+    if ! echo "$PS1" | grep -q SINGULARITY_NAME && [ ! -z "$SINGULARITY_NAME" ]; then
+        # proposed in https://github.com/datalad/datalad-container/pull/84
+        if [ ! -z "${DATALAD_CONTAINER_NAME:-}" ]; then
+            _name="$DATALAD_CONTAINER_NAME"
+        elif echo "$SINGULARITY_NAME" | grep -q '^MD5E-'; then
+            # singularity < 3. dereferences symlinks -
+            # annexed keys are too long/useless in this context, we shorten
+            _name=$(echo ${SINGULARITY_NAME##*--} | cut -c 1-8)...
+        else
+            _name="$SINGULARITY_NAME"
+        fi
+        # strip our possible suffix
+        _name="$(echo $_name | sed -e 's,.sing$,,g')"
+        export PS1="singularity:$_name > $PS1"
     fi
 fi
 

scripts/singularity_cmd

@@ -42,6 +42,10 @@ updir=$(dirname "$thisdir")
 
 cmd="$1"; shift
 
+if [ ! -z "${DATALAD_CONTAINER_NAME:-}" ]; then
+	export SINGULARITYENV_DATALAD_CONTAINER_NAME="$DATALAD_CONTAINER_NAME"
+fi
+
 # singularity bind mounts system /tmp, which might result in side-effects
 # Create a dedicated temporary directory to be removed upon completion
 tmpdir=$(mktemp -d --suffix=singtmp)