[__directory] Add --state exists and --state pre-exists

cdist/conf/type/__directory/gencode-remote

@@ -3,6 +3,7 @@
 # 2011-2013 Nico Schottelius (nico-cdist at schottelius.org)
 # 2013 Steven Armstrong (steven-cdist armstrong.cc)
 # 2014 Daniel Heule (hda at sfs.biz)
+# 2020 Dennis Camera (dennis.camera at ssrq-sds-fds.ch)
 #
 # This file is part of cdist.
 #
@@ -21,8 +22,8 @@
 #
 
 destination="/$__object_id"
-state_should="$(cat "$__object/parameter/state")"
+state_should=$(cat "$__object/parameter/state")
-type="$(cat "$__object/explorer/type")"
+type=$(cat "$__object/explorer/type")
 stat_file="$__object/explorer/stat"
 
 # variable to keep track if we have to set directory attributes
@@ -72,7 +73,7 @@ set_mode() {
 }
 
 case "$state_should" in
-   present)
+   present|exists)
       if [ "$type" != "directory" ]; then
          set_attributes=1
          if [ "$type" != "none" ]; then
@@ -83,6 +84,10 @@ case "$state_should" in
          fi
          echo "mkdir $mkdiropt '$destination'"
          echo "create" >> "$__messages_out"
+      elif [ "$state_should" = 'exists' ]; then
+         # The type is directory and --state exists. We are done and do not
+         # check or set the attributes.
+         exit 0
       fi
 
       # Note: Mode - needs to happen last as a chown/chgrp can alter mode by
@@ -103,6 +108,12 @@ case "$state_should" in
          fi
       done
    ;;
+   pre-exists)
+      if [ "$type" != "directory" ]; then
+         echo "Directory \"$destination\" does not exist" >&2
+         exit 1
+      fi
+   ;;
    absent)
         if [ "$type" = "directory" ]; then
             echo "rm -rf '$destination'"

cdist/conf/type/__directory/man.rst

@@ -19,7 +19,18 @@ None.
 OPTIONAL PARAMETERS
 -------------------
 state
-   'present' or 'absent', defaults to 'present'
+   'present', 'absent', 'exists' or 'pre-exists', defaults to 'present' where:
+
+   present
+      the directory exists and the given attributes are set.
+   absent
+      the directory does not exist.
+   exists
+      the directory exists, but its attributes are not altered if it already
+      existed.
+   pre-exists
+      check that the directory exists and is indeed a directory, but do not
+      create or modify it.
 
 group
    Group to chgrp to.
@@ -36,7 +47,7 @@ BOOLEAN PARAMETERS
 parents
    Whether to create parents as well (mkdir -p behaviour).
    Warning: all intermediate directory permissions default
-   to whatever mkdir -p does. 
+   to whatever mkdir -p does.
 
    Usually this means root:root, 0700.