scripts/docker-cleanup.sh: conditional img clean

Only run the simple image clean code if docuum is not running. It works
well enough in most cases, but has the drawbacks that it never deletes
"latest" images or images not matching "^osmocom-build", and may delete
images that are still being used (OS#5447). With the other tool, all
images are considered for removal, and the ones that have not been used
the longest time are removed first.

Related: OS#5477, OS#5066, SYS#5827
Change-Id: I1cef0833c096de0fa5acf77156bb5dd362e2ef9c

scripts/docker-cleanup.sh

@@ -1,10 +1,14 @@
 #!/bin/sh -x
+# https://osmocom.org/projects/osmocom-servers/wiki/Docker_cache_clean_up
 
+# simple image cleaning code in case docuum isn't running
 # delete all but the latest images
-IMAGES=`docker image ls | grep \^osmocom-build | grep -v latest  | awk -F ' ' '{print $1":"$2}'`
-for f in $IMAGES; do
-	docker image rm $f
-done
+if [ -z "$(docker ps -q -f name=docuum)" ]; then
+	IMAGES=`docker image ls | grep \^osmocom-build | grep -v latest  | awk -F ' ' '{print $1":"$2}'`
+	for f in $IMAGES; do
+		docker image rm $f
+	done
+fi
 
 # delete all containers where we forgot to use --rm with docker run
 CONTAINERS="$(docker ps -q -a -f status=exited -f status=created)"