fix(exec-wrapper): Updated technique for getting container name so it works with docker > 20.10 (#220)

Author: dazuma

app-engine-exec-wrapper/execute.sh

@@ -69,7 +69,10 @@ if [ -z "${IMAGE}" ]; then
   exit 1
 fi
 
-CONTAINER=$(cat /proc/1/cgroup | sed -n 's|^.*/docker/\([a-f0-9]*\)|\1|p' | awk 'NR==1')
+CONTAINER=$(cat /proc/self/mountinfo | sed -n 's|^.*/docker/containers/\([a-f0-9]*\)/.*$|\1|p' | awk 'NR==1')
+if [ -z "$CONTAINER" ]; then
+  CONTAINER=$(cat /proc/1/cgroup | sed -n 's|^.*/docker/\([a-f0-9]*\)|\1|p' | awk 'NR==1')
+fi
 if [ -z "$CONTAINER" ]; then
   CONTAINER=$(basename $(cat /proc/1/cpuset))
 fi