Feature: Cli-flags for controlling the dumping behavior (kapicorp#861)

* Added presenter for multiline-strings (kapicorp#852)

* Add different presenter for null-values (kapicorp#843)

* Applied Formatting

* Added cli-flag functionality for dumping behavior

* Changed argument names

* Fixed Bug when flag was not enabled

* Added exception handling

* Applied code style

* Applied naming suggestions

* Added documentation for yaml-cli-flags

* Changed how to get args from cached

* Applied suggestion how to get args

docs/usage.md

@@ -79,6 +79,10 @@ optional arguments:
                         ignore the version from .kapitan
   --schemas-path SCHEMAS_PATH
                         set schema cache path, default is "./schemas"
+  --yaml-multiline-string-style STYLE
+                        set multiline string style to STYLE, default is 'double-quotes'
+  --yaml-dump-null-as-empty
+                        dumps all none-type entries as empty, default is dumping as 'null'
   --targets TARGET [TARGET ...], -t TARGET [TARGET ...]
                         targets to compile, default is all
   --labels [key=value [key=value ...]], -l [key=value [key=value ...]]

kapitan/cli.py

@@ -270,6 +270,23 @@ def build_parser():
         help='set schema cache path, default is "./schemas"',
     )
 
+    compile_parser.add_argument(
+        "--yaml-multiline-string-style",
+        type=str,
+        choices=["literal", "folded", "double-quotes"],
+        metavar="STYLE",
+        action="store",
+        default=from_dot_kapitan("compile", "yaml-multiline-string-style", "double-quotes"),
+        help="set multiline string style to STYLE, default is 'double-quotes'",
+    )
+
+    compile_parser.add_argument(
+        "--yaml-dump-null-as-empty",
+        default=from_dot_kapitan("compile", "yaml-dump-null-as-empty", False),
+        action="store_true",
+        help="dumps all none-type entries as empty, default is dumping as 'null'",
+    )
+
     compile_selector_parser = compile_parser.add_mutually_exclusive_group()
     compile_selector_parser.add_argument(
         "--targets",

kapitan/utils.py

@@ -212,6 +212,49 @@ def increase_indent(self, flow=False, indentless=False):
         return super(PrettyDumper, self).increase_indent(flow, False)
 
 
+def multiline_str_presenter(dumper, data):
+    """
+    Configures yaml for dumping multiline strings with given style.
+    By default, strings are getting dumped with style='"'.
+    Ref: https://github.com/yaml/pyyaml/issues/240#issuecomment-1018712495
+    """
+    # get parsed args from cached.py
+    compile_args = cached.args.get("compile", None)
+    style = None
+    if compile_args:
+        style = compile_args.yaml_multiline_string_style
+
+    if style == "literal":
+        style = "|"
+    elif style == "folded":
+        style = ">"
+    else:
+        style = '"'
+    if data.count("\n") > 0:  # check for multiline string
+        return dumper.represent_scalar("tag:yaml.org,2002:str", data, style=style)
+    return dumper.represent_scalar("tag:yaml.org,2002:str", data)
+
+
+PrettyDumper.add_representer(str, multiline_str_presenter)
+
+
+def null_presenter(dumper, data):
+    """Configures yaml for omitting value from null-datatype"""
+    # get parsed args from cached.py
+    compile_args = cached.args.get("compile", None)
+    flag_value = None
+    if compile_args:
+        flag_value = compile_args.yaml_dump_null_as_empty
+
+    if flag_value:
+        return dumper.represent_scalar("tag:yaml.org,2002:null", "")
+    else:
+        return dumper.represent_scalar("tag:yaml.org,2002:null", "null")
+
+
+PrettyDumper.add_representer(type(None), null_presenter)
+
+
 def flatten_dict(d, parent_key="", sep="."):
     """Flatten nested elements in a dictionary"""
     items = []