Support for multiline line string dump without \n (#17)

* Added support for dumping multiline strings without using \n

* Added the multi line string block representer under a flag

Author: ecojan

himl/config_generator.py

@@ -26,7 +26,7 @@
 class ConfigProcessor(object):
 
     def process(self, cwd=None, path=None, filters=(), exclude_keys=(), enclosing_key=None, remove_enclosing_key=None, output_format="yaml",
-                print_data=False, output_file=None, skip_interpolations=False, skip_interpolation_validation=False, skip_secrets=False):
+                print_data=False, output_file=None, skip_interpolations=False, skip_interpolation_validation=False, skip_secrets=False, multi_line_string=False):
 
         path = self.get_relative_path(path)
 
@@ -39,7 +39,7 @@ def process(self, cwd=None, path=None, filters=(), exclude_keys=(), enclosing_ke
         if cwd is None:
             cwd = os.getcwd()
 
-        generator = ConfigGenerator(cwd, path)
+        generator = ConfigGenerator(cwd, path, multi_line_string)
         generator.generate_hierarchy()
         generator.process_hierarchy()
 
@@ -112,13 +112,16 @@ class ConfigGenerator(object):
     will contain merged data on each layer.
     """
 
-    def __init__(self, cwd, path):
+    def __init__(self, cwd, path, multi_line_string):
         self.cwd = cwd
         self.path = path
         self.hierarchy = self.generate_hierarchy()
         self.generated_data = OrderedDict()
         self.interpolation_validator = InterpolationValidator()
 
+        if multi_line_string is True:
+            yaml.representer.BaseRepresenter.represent_scalar = ConfigGenerator.custom_represent_scalar
+
     @staticmethod
     def yaml_dumper():
         try:
@@ -267,3 +270,27 @@ def resolve_secrets(self, default_aws_profile):
 
     def validate_interpolations(self):
         self.interpolation_validator.check_all_interpolations_resolved(self.generated_data)
+
+    @staticmethod
+    def should_use_block(value):
+        """
+        https://stackoverflow.com/questions/8640959/how-can-i-control-what-scalar-form-pyyaml-uses-for-my-data
+        """
+
+        for c in u"\u000a\u000d\u001c\u001d\u001e\u0085\u2028\u2029":
+            if c in value:
+                return True
+        return False
+
+    @staticmethod
+    def custom_represent_scalar(self, tag, value, style=None):
+        if style is None:
+            if ConfigGenerator.should_use_block(value):
+                style = '|'
+            else:
+                style = self.default_style
+
+        node = yaml.representer.ScalarNode(tag, value, style=style)
+        if self.alias_key is not None:
+            self.represented_objects[self.alias_key] = node
+        return node

himl/main.py

@@ -31,7 +31,7 @@ def do_run(self, opts):
         config_processor = ConfigProcessor()
         config_processor.process(cwd, opts.path, filters, excluded_keys, opts.enclosing_key, opts.remove_enclosing_key,
                                  opts.output_format, opts.print_data, opts.output_file, opts.skip_interpolation_resolving,
-                                 opts.skip_interpolation_validation, opts.skip_secrets)
+                                 opts.skip_interpolation_validation, opts.skip_secrets, opts.multi_line_string)
 
     @staticmethod
     def get_parser(parser=None):
@@ -61,6 +61,8 @@ def get_parser(parser=None):
                             help='remove enclosed data from under a common key')
         parser.add_argument('--cwd', dest='cwd', type=str, default="",
                             help='the working directory')
+        parser.add_argument('--multi-line-string', action='store_true',
+                            help='will overwrite the global yaml dumper to use block style')
         return parser