[document-end] adds min/max empty lines before

yamllint/rules/document_end.py

@@ -21,6 +21,10 @@
 
 * Set ``present`` to ``true`` when the document end marker is required, or to
   ``false`` when it is forbidden.
+* ``min-empty-lines-before`` defines the minimal number of empty lines before
+  the document end marker.
+* ``max-empty-lines-before`` defines the maximal number of empty lines before
+  the document end marker.
 
 .. rubric:: Default values (when enabled)
 
@@ -89,8 +93,12 @@
 
 ID = 'document-end'
 TYPE = 'token'
-CONF = {'present': bool}
-DEFAULT = {'present': True}
+CONF = {'present': bool,
+        'max-empty-lines-before': int,
+        'min-empty-lines-before': int}
+DEFAULT = {'present': True,
+           'max-empty-lines-before': -1,
+           'min-empty-lines-before': 0}
 
 
 def check(conf, token, prev, next, nextnext, context):
@@ -108,6 +116,21 @@ def check(conf, token, prev, next, nextnext, context):
             yield LintProblem(token.start_mark.line + 1, 1,
                               'missing document end "..."')
 
+        if isinstance(next, yaml.DocumentEndToken):
+            empty_lines = next.start_mark.line - token.start_mark.line - 1
+
+            if (conf['max-empty-lines-before'] >= 0 and
+                    empty_lines > conf['max-empty-lines-before']):
+                yield LintProblem(token.start_mark.line + 1,
+                                  token.start_mark.column + 1,
+                                  'too many empty lines before document end')
+
+            if (conf['min-empty-lines-before'] > 0 and
+                    empty_lines < conf['min-empty-lines-before']):
+                yield LintProblem(token.start_mark.line + 1,
+                                  token.start_mark.column + 1,
+                                  'too few empty lines before document end')
+
     else:
         if isinstance(token, yaml.DocumentEndToken):
             yield LintProblem(token.start_mark.line + 1,