feat(cfn-lang-ext): add jmespath-aware property get/set helpers

Author: bnusunny

samcli/lib/package/language_extensions_packaging.py

@@ -8,12 +8,14 @@
 
 import copy
 import itertools
+import jmespath
 import logging
 import re
 from collections import Counter
 from typing import Any, Dict, List, Optional, Tuple
 
 import click
+from botocore.utils import set_value_from_jmespath
 
 from samcli.lib.cfn_language_extensions.models import (
     PACKAGEABLE_RESOURCE_ARTIFACT_PROPERTIES,
@@ -118,6 +120,22 @@ def generate_and_apply_artifact_mappings(
     return _apply_artifact_mappings_to_template(template, mappings, dynamic_properties, property_to_mapping)
 
 
+def _get_prop_value(props: Dict[str, Any], prop_name: str) -> Optional[Any]:
+    """Read a property by jmespath path. Supports flat keys ("CodeUri") and
+    dotted paths ("Command.ScriptLocation"). Returns None if missing.
+    """
+    if not isinstance(props, dict):
+        return None
+    return jmespath.search(prop_name, props)
+
+
+def _set_prop_value(props: Dict[str, Any], prop_name: str, value: Any) -> None:
+    """Write a property by jmespath path. Creates intermediate dicts as needed.
+    Supports flat keys and dotted paths.
+    """
+    set_value_from_jmespath(props, prop_name, value)
+
+
 # ---------------------------------------------------------------------------
 # Merge helpers
 # ---------------------------------------------------------------------------

tests/unit/commands/package/test_package_context.py

@@ -975,6 +975,33 @@ def test_apply_artifact_mappings_to_template_integration(self):
         code_uri = body["${Name}Service"]["Properties"]["CodeUri"]
         self.assertEqual(code_uri, {"Fn::FindInMap": ["SAMCodeUriServices", {"Ref": "Name"}, "CodeUri"]})
 
+    def test_get_prop_value_flat_key(self):
+        from samcli.lib.package.language_extensions_packaging import _get_prop_value
+        self.assertEqual(_get_prop_value({"CodeUri": "s3://b/k"}, "CodeUri"), "s3://b/k")
+
+    def test_get_prop_value_dotted_key(self):
+        from samcli.lib.package.language_extensions_packaging import _get_prop_value
+        props = {"Command": {"ScriptLocation": "s3://b/k.py"}}
+        self.assertEqual(_get_prop_value(props, "Command.ScriptLocation"), "s3://b/k.py")
+
+    def test_get_prop_value_missing_returns_none(self):
+        from samcli.lib.package.language_extensions_packaging import _get_prop_value
+        self.assertIsNone(_get_prop_value({"CodeUri": "x"}, "Command.ScriptLocation"))
+
+    def test_set_prop_value_flat_key(self):
+        from samcli.lib.package.language_extensions_packaging import _set_prop_value
+        props = {"CodeUri": "./src"}
+        _set_prop_value(props, "CodeUri", "s3://b/k")
+        self.assertEqual(props["CodeUri"], "s3://b/k")
+
+    def test_set_prop_value_dotted_key_creates_intermediate(self):
+        from samcli.lib.package.language_extensions_packaging import _set_prop_value
+        props = {"Command": {"Name": "glueetl"}}
+        _set_prop_value(props, "Command.ScriptLocation", "s3://b/k.py")
+        self.assertEqual(props["Command"]["ScriptLocation"], "s3://b/k.py")
+        # Existing keys preserved
+        self.assertEqual(props["Command"]["Name"], "glueetl")
+
 
 class TestPackageContextMappingsIntegration(TestCase):
     """Test cases for the complete Mappings transformation integration in _export()"""