Add the configfile module.

modules/configfile

@@ -0,0 +1,83 @@
+#!/usr/bin/python
+from __future__ import print_function 
+
+ANSIBLE_METADATA = {
+    'metadata_version': '1.0',
+    'status': ['preview'],
+    'supported_by': 'ISTI-CNR'
+}
+
+import glob
+import json
+
+import tempfile
+import filecmp
+import os
+import re
+from ansible.module_utils.basic import AnsibleModule
+
+def run_configfile_module():
+    module = AnsibleModule(
+        argument_spec = dict(
+            path=dict(required=True),
+            key=dict(required=True),
+            value=dict(required=True),
+            syntax=dict(required=False, choices=['standard', 'shell'], default='standard'),
+            )
+        )
+
+    path = module.params['path']
+    syntax = module.params['syntax']
+    key = module.params['key']
+    value = module.params['value']
+
+    found = [False]
+
+    def expand(line):
+        if syntax == 'standard':
+            if re.match("[ #]*%s *=.*" % (key), line):
+                found[0] = True
+            return re.sub("[ #]*%s *=.*" % (key), "%s = %s" % (key, value), line)
+        elif syntax == 'shell':
+            if re.match("[ #]*%s *=.*" % (key), line):
+                found[0] = True
+            return re.sub("[ #]*%s *=.*" % (key), "%s=%s" % (key, value), line)
+        else:
+            raise Exception("unsupported syntax %s" % syntax)
+
+    changed = False
+
+    with open(path) as input:
+        with tempfile.NamedTemporaryFile(dir=os.path.dirname(path)) as temp:
+            for line in input:
+                print(expand(line), end=' ', file=temp)
+
+            if not found[0]:
+                if not line.endswith('\n'):
+                    print('', file=temp)
+                if syntax == 'standard':
+                    print("%s = %s" % (key, value), file=temp)
+                elif syntax == 'shell':
+                    print("%s=%s" % (key, value), file=temp)
+                else:
+                    raise Exception("unsupported syntax %s" % syntax)
+
+            temp.delete = False
+            temp.close()
+
+            changed = not filecmp.cmp(path, temp.name)
+            if changed:
+                os.rename(temp.name, path)
+            else:
+                os.remove(temp.name)
+
+    module.exit_json(changed=changed)
+
+# include magic from lib/ansible/module_common.py
+#<<INCLUDE_ANSIBLE_MODULE_COMMON>>
+def main():
+    run_configfile_module()
+
+if __name__ == '__main__':
+    main()
+