Add from_yaml_all to support multi document yaml strings (#43037)

* Support multi-doc yaml in the from_yaml filter

* Most automatic method of handling multidoc

* Only use safe_load_all

* Implement separate filter

* Update plugin docs and changelog

changelogs/fragments/from_yaml_all_filter_plugin.yaml

@@ -0,0 +1,5 @@
+---
+minor_changes:
+  - Added the from_yaml_all filter to parse multi-document yaml strings.
+    Refer to the appropriate entry which as been added to user_guide
+    playbooks_filters.rst document.

docs/docsite/rst/user_guide/playbooks_filters.rst

@@ -47,6 +47,22 @@ for example::
     - set_fact:
         myvar: "{{ result.stdout | from_json }}"
 
+
+.. versionadded:: 2.7
+
+To parse multi-document yaml strings, the ``from_yaml_all`` filter is provided.
+The ``from_yaml_all`` filter will return a generator of parsed yaml documents.
+
+for example::
+
+  tasks:
+    - shell: cat /some/path/to/multidoc-file.yaml
+      register: result
+   - debug:
+       msg: '{{ item }}'
+    loop: '{{ result.stdout | from_yaml_all | list }}'
+
+
 .. _forcing_variables_to_be_defined:
 
 Forcing Variables To Be Defined

lib/ansible/plugins/filter/core.py

@@ -210,6 +210,12 @@ def from_yaml(data):
     return data
 
 
+def from_yaml_all(data):
+    if isinstance(data, string_types):
+        return yaml.safe_load_all(data)
+    return data
+
+
 @environmentfilter
 def rand(environment, end, start=None, step=None, seed=None):
     if seed is None:
@@ -600,6 +606,7 @@ class FilterModule(object):
             'to_yaml': to_yaml,
             'to_nice_yaml': to_nice_yaml,
             'from_yaml': from_yaml,
+            'from_yaml_all': from_yaml_all,
 
             # path
             'basename': partial(unicode_wrap, os.path.basename),