fix: build strings for complex types differently for Terraform/Packer commands

strong_opx/hcl/runner.py

@@ -1,6 +1,6 @@
 import os
 import subprocess
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Any
 
 from strong_opx.exceptions import UndefinedVariableError
 from strong_opx.hcl.extractor import HCLVariableExtractor
@@ -18,6 +18,51 @@ def __init__(self, environment: "Environment", directory: str):
         self.environment = environment
         self.directory = directory
 
+    @staticmethod
+    def _serialize_value(value: Any) -> str:
+        """
+        Converts a variable value to a string that can be used as an environment variable that will be passed to a
+        Terraform or Packer command.
+
+        Per Terraform documentation:
+        https://developer.hashicorp.com/terraform/cli/commands/plan#input-variables-on-the-command-line
+
+        string, number, and bool values are expected to be passed as strings with no special punctuation. For all other
+        type constraints, including list, map, and set types and the special any keyword, you must write a valid
+        Terraform language expression representing the value, and write any necessary quoting or escape characters to
+        ensure it will pass through your shell literally to Terraform.
+
+        Packer documentation does not explicitly call this out, but, in testing, this code works for Packer as well.
+
+        NOTE: This method does NOT handle Windows command line escaping, so it should only be used in Unix environments.
+        strong-opx does not currently support Windows, but I wanted to explicitly call it out here.
+        """
+        if isinstance(value, list) or isinstance(value, tuple):
+            build_string = "["
+            for item in value:
+                if isinstance(item, str):
+                    build_string += f'"{item}",'
+                else:
+                    build_string += f"{HCLRunner._serialize_value(item)},"
+            if build_string.endswith(","):
+                build_string = build_string[:-1]  # remove trailing comma
+            build_string += "]"
+            return build_string
+        elif isinstance(value, dict):
+            build_string = "{"
+            for key, val in value.items():
+                if isinstance(val, str):
+                    build_string += f'"{key}": "{val}",'
+                else:
+                    build_string += f'"{key}": {HCLRunner._serialize_value(val)},'
+            if build_string.endswith(","):
+                build_string = build_string[:-1]  # remove trailing comma
+
+            build_string += "}"
+
+            return build_string
+        return str(value)
+
     def extract_vars(self) -> dict[str, str]:
         env_dict = {}
         extractor = HCLVariableExtractor()
@@ -36,14 +81,14 @@ def extract_vars(self) -> dict[str, str]:
                 missing_vars.append(var)
                 continue
 
-            env_dict[f"{self.env_var_prefix}_{var}"] = str(context[var])
+            env_dict[f"{self.env_var_prefix}_{var}"] = self._serialize_value(context[var])
 
         if missing_vars:
             raise UndefinedVariableError(*missing_vars)
 
         for var in extractor.optional_vars:
             if var in context:
-                env_dict[f"{self.env_var_prefix}_{var}"] = str(context[var])
+                env_dict[f"{self.env_var_prefix}_{var}"] = self._serialize_value(context[var])
 
         return env_dict
 

tests/hcl/test_runner.py

@@ -55,15 +55,38 @@ def test_variable_extraction_only_from_whitelisted_files(
     @mock.patch("strong_opx.hcl.runner.HCLVariableExtractor")
     def test_required_and_optional_vars_with_none_missing(self, extractor_mock: mock.Mock, listdir_mock: mock.Mock):
         listdir_mock.return_value = []
-        extractor_mock.return_value.required_vars = ["VAR_1", "VAR_2"]
-        extractor_mock.return_value.optional_vars = ["VAR_3"]
+        extractor_mock.return_value.required_vars = ["VAR_1", "VAR_2", "ARRAY_OF_INTS", "MIXED_ARRAY", "TUPLE"]
+        extractor_mock.return_value.optional_vars = ["ARRAY_OF_STRINGS", "ARRAY_OF_ARRAYS_OF_STRINGS", "NESTED_MIX"]
 
         runner = TestHCLRunner()
-        runner.environment.context = Context({"VAR_1": "VAL_1", "VAR_2": "VAL_2", "VAR_3": "VAL_3"})
+        runner.environment.context = Context(
+            {
+                "VAR_1": "VAL_1",
+                "VAR_2": 2,
+                "ARRAY_OF_STRINGS": ["VAL_3_1", "VAL_3_2"],
+                "ARRAY_OF_INTS": [1, 2, 3],
+                "ARRAY_OF_ARRAYS_OF_STRINGS": [["VAL_4_1_1", "VAL_4_1_2"], ["VAL_4_2_1", "VAL_4_2_2"]],
+                "MIXED_ARRAY": ["VAL_5_1", 2, ["VAL_5_3_1", "VAL_5_3_2"]],
+                "NESTED_MIX": {"KEY1": "VAL_6_1", "KEY2": ["VAL_6_2_1", "VAL_6_2_2"]},
+                "TUPLE": ("TUPLE_1", "TUPLE_2"),
+            }
+        )
 
         actual_result = runner.extract_vars()
 
-        self.assertDictEqual({"T_VAR_1": "VAL_1", "T_VAR_2": "VAL_2", "T_VAR_3": "VAL_3"}, actual_result)
+        self.assertDictEqual(
+            {
+                "T_VAR_1": "VAL_1",
+                "T_VAR_2": "2",
+                "T_ARRAY_OF_STRINGS": '["VAL_3_1","VAL_3_2"]',
+                "T_ARRAY_OF_INTS": "[1,2,3]",
+                "T_ARRAY_OF_ARRAYS_OF_STRINGS": '[["VAL_4_1_1","VAL_4_1_2"],["VAL_4_2_1","VAL_4_2_2"]]',
+                "T_MIXED_ARRAY": '["VAL_5_1",2,["VAL_5_3_1","VAL_5_3_2"]]',
+                "T_NESTED_MIX": '{"KEY1": "VAL_6_1","KEY2": ["VAL_6_2_1","VAL_6_2_2"]}',
+                "T_TUPLE": '["TUPLE_1","TUPLE_2"]',
+            },
+            actual_result,
+        )
 
     @mock.patch("strong_opx.hcl.runner.os.listdir")
     @mock.patch("strong_opx.hcl.runner.HCLVariableExtractor")