feat: Add YAML config file option

samcli/lib/config/file_manager.py

@@ -9,6 +9,8 @@
 from typing import Any
 
 import tomlkit
+from ruamel.yaml import YAML, YAMLError
+from ruamel.yaml.compat import StringIO
 
 from samcli.lib.config.exceptions import FileParseException
 
@@ -159,3 +161,102 @@ def put_comment(document: dict, comment: str) -> Any:
     def _to_toml(document: dict) -> tomlkit.TOMLDocument:
         """Ensure that a dictionary-like object is a TOMLDocument."""
         return tomlkit.parse(tomlkit.dumps(document))
+
+
+class YamlFileManager(FileManager):
+    """
+    Static class to read and write yaml files.
+    """
+
+    yaml = YAML()
+    file_format = "YAML"
+
+    @staticmethod
+    def read(filepath: Path) -> Any:
+        """
+        Read a YAML file at the given path.
+
+        Parameters
+        ----------
+        filepath: Path
+            The Path object that points to the file to be read.
+
+        Returns
+        -------
+        Any
+            A dictionary-like yaml object, which represents the contents of the YAML file at the
+            provided location.
+        """
+        yaml_doc = YamlFileManager.yaml.load("")
+        try:
+            yaml_doc = YamlFileManager.yaml.load(filepath.read_text())
+        except OSError as e:
+            LOG.debug(f"OSError occurred while reading {YamlFileManager.file_format} file: {str(e)}")
+        except YAMLError as e:
+            raise FileParseException(e) from e
+
+        return yaml_doc
+
+    @staticmethod
+    def write(document: dict, filepath: Path):
+        """
+        Write the contents of a dictionary to a YAML file at the provided location.
+
+        Parameters
+        ----------
+        document: dict
+            The object to write.
+        filepath: Path
+            The final location for the YAML file to be written.
+        """
+        if not document:
+            LOG.debug("No document given to YamlFileManager to write.")
+            return
+
+        yaml_doc = YamlFileManager._to_yaml(document)
+
+        if yaml_doc.get(COMMENT_KEY, None):  # Comment appears at the top of doc
+            yaml_doc.yaml_set_start_comment(document[COMMENT_KEY])
+            yaml_doc.pop(COMMENT_KEY)
+
+        YamlFileManager.yaml.dump(yaml_doc, filepath)
+
+    @staticmethod
+    def put_comment(document: Any, comment: str) -> Any:
+        """
+        Put a comment in a document object.
+
+        Parameters
+        ----------
+        document: Any
+            The yaml object to write
+        comment: str
+            The comment to include in the document.
+
+        Returns
+        -------
+        Any
+            The new yaml document, with the comment added to it.
+        """
+        document = YamlFileManager._to_yaml(document)
+        document.yaml_set_start_comment(comment)
+        return document
+
+    @staticmethod
+    def _to_yaml(document: dict) -> Any:
+        """
+        Ensure a dictionary-like object is a YAML document.
+
+        Parameters
+        ----------
+        document: dict
+            A dictionary-like object to parse.
+
+        Returns
+        -------
+        Any
+            A dictionary-like YAML object, as derived from `yaml.load()`.
+        """
+        with StringIO() as stream:
+            YamlFileManager.yaml.dump(document, stream)
+            return YamlFileManager.yaml.load(stream.getvalue())

samcli/lib/config/samconfig.py

@@ -8,7 +8,7 @@
 from typing import Any, Dict, Iterable, Type
 
 from samcli.lib.config.exceptions import FileParseException, SamConfigFileReadException, SamConfigVersionException
-from samcli.lib.config.file_manager import FileManager, TomlFileManager
+from samcli.lib.config.file_manager import FileManager, TomlFileManager, YamlFileManager
 from samcli.lib.config.version import SAM_CONFIG_VERSION, VERSION_KEY
 
 LOG = logging.getLogger(__name__)
@@ -26,6 +26,8 @@ class SamConfig:
 
     FILE_MANAGER_MAPPER: Dict[str, Type[FileManager]] = {
         ".toml": TomlFileManager,
+        ".yaml": YamlFileManager,
+        ".yml": YamlFileManager,
     }
 
     def __init__(self, config_dir, filename=None):

tests/unit/commands/samconfig/test_samconfig.py

@@ -14,7 +14,9 @@
 from unittest import TestCase
 from unittest.mock import patch, ANY
 import logging
+from parameterized import parameterized
 from samcli.lib.config.exceptions import SamConfigFileReadException
+from samcli.lib.config.file_manager import YamlFileManager
 
 from samcli.lib.config.samconfig import SamConfig, DEFAULT_ENV, TomlFileManager
 from samcli.lib.utils.packagetype import ZIP, IMAGE
@@ -1254,13 +1256,20 @@ def test_file_manager_not_declared(self):
         with self.assertRaises(SamConfigFileReadException):
             SamConfig(config_path, filename="samconfig")
 
-    def test_file_manager_toml(self):
+    @parameterized.expand(
+        [
+            ("samconfig.toml", TomlFileManager),
+            ("samconfig.yaml", YamlFileManager),
+            ("samconfig.yml", YamlFileManager),
+        ]
+    )
+    def test_file_manager(self, filename, expected_file_manager):
         config_dir = tempfile.gettempdir()
-        config_path = Path(config_dir, "samconfig.toml")
+        config_path = Path(config_dir, filename)
 
-        samconfig = SamConfig(config_path, filename="samconfig.toml")
+        samconfig = SamConfig(config_path, filename=filename)
 
-        self.assertIs(samconfig.file_manager, TomlFileManager)
+        self.assertIs(samconfig.file_manager, expected_file_manager)
 
 
 @contextmanager

tests/unit/lib/samconfig/test_file_manager.py

@@ -3,9 +3,10 @@
 from unittest import TestCase
 
 import tomlkit
-from samcli.lib.config.exceptions import FileParseException
+from ruamel.yaml import YAML
 
-from samcli.lib.config.file_manager import COMMENT_KEY, TomlFileManager
+from samcli.lib.config.exceptions import FileParseException
+from samcli.lib.config.file_manager import COMMENT_KEY, TomlFileManager, YamlFileManager
 
 
 class TestTomlFileManager(TestCase):
@@ -48,6 +49,7 @@ def test_write_toml(self):
         self.assertIn("[config_env.topic2.parameters]", txt)
         self.assertIn('word = "clarity"', txt)
         self.assertIn("# This is a comment", txt)
+        self.assertNotIn(COMMENT_KEY, txt)
 
     def test_dont_write_toml_if_empty(self):
         config_dir = tempfile.gettempdir()
@@ -99,3 +101,81 @@ def test_toml_put_comment(self):
 
         txt = tomlkit.dumps(toml_doc)
         self.assertIn("# This is a comment", txt)
+
+
+class TestYamlFileManager(TestCase):
+
+    yaml = YAML()
+
+    def test_read_yaml(self):
+        config_dir = tempfile.gettempdir()
+        config_path = Path(config_dir, "samconfig.yaml")
+        config_path.write_text("version: 0.1\nconfig_env:\n  topic1:\n    parameters:\n      word: clarity\n")
+
+        config_doc = YamlFileManager.read(config_path)
+
+        self.assertEqual(
+            config_doc,
+            {"version": 0.1, "config_env": {"topic1": {"parameters": {"word": "clarity"}}}},
+        )
+
+    def test_read_yaml_invalid_yaml(self):
+        config_dir = tempfile.gettempdir()
+        config_path = Path(config_dir, "samconfig.yaml")
+        config_path.write_text("fake: not real\nthisYaml isn't correct")
+
+        with self.assertRaises(FileParseException):
+            YamlFileManager.read(config_path)
+
+    def test_read_yaml_file_path_not_valid(self):
+        config_dir = "path/that/doesnt/exist"
+        config_path = Path(config_dir, "samconfig.yaml")
+
+        config_doc = YamlFileManager.read(config_path)
+
+        self.assertEqual(config_doc, self.yaml.load(""))
+
+    def test_write_yaml(self):
+        config_dir = tempfile.gettempdir()
+        config_path = Path(config_dir, "samconfig.yaml")
+        yaml = {
+            "version": 0.1,
+            "config_env": {"topic2": {"parameters": {"word": "clarity"}}},
+            COMMENT_KEY: "This is a comment",
+        }
+
+        YamlFileManager.write(yaml, config_path)
+
+        txt = config_path.read_text()
+        self.assertIn("version: 0.1", txt)
+        self.assertIn("config_env:\n  topic2:\n    parameters:\n", txt)
+        self.assertIn("word: clarity", txt)
+        self.assertIn("# This is a comment", txt)
+        self.assertNotIn(COMMENT_KEY, txt)
+
+    def test_dont_write_yaml_if_empty(self):
+        config_dir = tempfile.gettempdir()
+        config_path = Path(config_dir, "samconfig.yaml")
+        config_path.write_text("nothing to see here\n")
+        yaml = {}
+
+        YamlFileManager.write(yaml, config_path)
+
+        self.assertEqual(config_path.read_text(), "nothing to see here\n")
+
+    def test_write_yaml_file_bad_path(self):
+        config_path = Path("path/to/some", "file_that_doesnt_exist.yaml")
+
+        with self.assertRaises(FileNotFoundError):
+            YamlFileManager.write(self.yaml.load("key: some value"), config_path)
+
+    def test_yaml_put_comment(self):
+        config_dir = tempfile.gettempdir()
+        config_path = Path(config_dir, "samconfig.yaml")
+        yaml_doc = self.yaml.load("version: 0.1\nconfig_env:\n  topic2:\n    parameters:\n      word: clarity\n")
+
+        yaml_doc = YamlFileManager.put_comment(yaml_doc, "This is a comment")
+
+        self.yaml.dump(yaml_doc, config_path)
+        txt = config_path.read_text()
+        self.assertIn("# This is a comment", txt)