Python DSC Adapter and Test Resource implementation by shammu1 · Pull Request #1520 · PowerShell/DSC

shammu1 · 2026-05-07T18:42:33Z

PR Summary

The Python adapter (Microsoft.DSC.Adapters/Python) enables DSC v3 to dynamically execute Python resource classes. It acts as a bridge between the DSC framework and Python-based resource implementations, handling all DSC operations (get, set, test, export, list, validate).

Key Features
Dynamic Resource Discovery: Reads resource mappings from pyproject.toml under [tool.dsc.resources]
Operation Routing: Routes DSC operations to appropriate Python resource class methods
Structured Logging: Full trace/debug/info/error logging with optional profiling capabilities
State Management: Handles JSON serialization and properly emits state + diffs per DSC specification
Error Handling: Graceful error handling with proper exit codes and stderr logging

Core Components
adapter.py: Main ResourceAdapter class managing operation routing, class loading, and resource discovery
discovery.py: Parses pyproject.toml and dynamically imports resource classes
cli.py: Command-line interface handling arguments and stdin input
dsc_logging.py: Environment variable-based logging configuration

Test Coverage
Three comprehensive test layers:

Unit Tests (Python/unittest) — Tests adapter internals: initialization, manifest discovery, class resolution, operation routing
Component Tests (Pester) — Validates adapter subprocess behavior directly: output shapes, exit codes, error handling
Integration Tests (Pester) — End-to-end DSC CLI integration testing through the full DSC framework

PR Context

DSC already supports adapters for non-native resource ecosystems, and this PR adds a Python adapter so Python-based resources can participate in the same DSC execution model as built-in and PowerShell resources.

This adapter is needed to:

Enable first-class Python resource support in DSC with the same get, set, test, export, list, and validate flow.
Improve extensibility of DSC by allowing teams with existing Python tooling and expertise to author/manage resources without switching implementation languages.

shammu1 · 2026-05-08T19:04:59Z

@microsoft-github-policy-service agree company="Microsoft"

shammu1 · 2026-05-15T16:02:49Z

@copilot Review this

Copilot

Pull request overview

Adds a new Python DSC adapter implementation with test fixtures and Pester/Python tests, intended to let DSC invoke Python resource classes through adapted resource manifests.

Changes:

Adds Python adapter manifest and pyDscAdapter CLI/runtime modules.
Adds Python test resources, manifests, pyproject mapping, and unit/component/integration tests.
Updates ignore rules and one PowerShell adapter test stderr redirection.

Reviewed changes

Copilot reviewed 21 out of 27 changed files in this pull request and generated 46 comments.

Show a summary per file

File	Description
`.gitignore`	Adds Visual Studio and Python cache ignores.
`adapters/__init__.py`	Adds package marker.
`adapters/powershell/Tests/powershellgroup.resource.tests.ps1`	Redirects stderr for one adapted-resource test.
`adapters/python/.project.data.json`	Defines Python adapter build project metadata.
`adapters/python/__init__.py`	Adds package marker.
`adapters/python/pythonadapter.dsc.resource.json`	Adds DSC adapter manifest for Python operations.
`adapters/python/pyDscAdapter/__init__.py`	Adds adapter package marker.
`adapters/python/pyDscAdapter/__main__.py`	Adds Python adapter entry point.
`adapters/python/pyDscAdapter/adapter.py`	Implements operation routing, class loading, logging, and profiling.
`adapters/python/pyDscAdapter/cli.py`	Adds command-line parser and stdin/input handling.
`adapters/python/pyDscAdapter/discovery.py`	Adds pyproject class-map parsing and dynamic file import.
`adapters/python/pyDscAdapter/dsc_logging.py`	Adds structured DSC-style logging.
`adapters/python/pyDscAdapter/utils.py`	Adds JSON parsing helper.
`adapters/python/tests/.project.data.json`	Defines test project copy metadata.
`adapters/python/tests/TEST_LAYERS.md`	Documents unit/component/integration test layers.
`adapters/python/tests/__init__.py`	Adds test package marker.
`adapters/python/tests/pythoncomponent.tests.ps1`	Adds adapter subprocess component tests.
`adapters/python/tests/pythonintegration.tests.ps1`	Adds DSC CLI integration tests.
`adapters/python/tests/pythonunit.tests.py`	Adds Python unittest coverage for adapter internals.
`adapters/python/tests/pyproject.toml`	Maps PythonTest resource types to fixture classes.
`adapters/python/tests/pythontest.dsc.manifests.json`	Adds adapted resource manifests for Python test resources.
`adapters/python/tests/src/.project.data.json`	Defines fixture resource copy metadata.
`adapters/python/tests/src/__init__.py`	Adds fixture package marker.
`adapters/python/tests/src/export.py`	Adds export-only fixture resource.
`adapters/python/tests/src/get.py`	Adds get-only fixture resource.
`adapters/python/tests/src/set.py`	Adds set fixture resource.
`adapters/python/tests/src/test.py`	Adds test-only fixture resource.

Copilot

Pull request overview

Copilot reviewed 21 out of 27 changed files in this pull request and generated 12 comments.

Copilot

Pull request overview

Copilot reviewed 22 out of 28 changed files in this pull request and generated 8 comments.

Copilot

Pull request overview

Copilot reviewed 22 out of 28 changed files in this pull request and generated 8 comments.

+# TODO: Currently using absolute imports. Switch to relative imports if this is later used as a module in the adapter manifest; otherwise, keep as-is for direct script execution.
+from dsc_logging import setup_dsc_logging, operation_context
+from discovery import get_class_map_from_pyproject, import_class_from_file


+from typing import Optional
+# TODO: Currently using absolute imports. Switch to relative imports if this is later used as a module in the adapter manifest; otherwise, keep as-is for direct script execution.
+from adapter import ResourceAdapter


@@ -0,0 +1,6 @@
+import sys
+from cli import main  # TODO: Currently using absolute imports. Switch to relative imports if this is later used as a module in the adapter manifest; otherwise, keep as-is for direct script execution.


+            except Exception as e:
+                self.log("error", str(e), "Adapter", operation=op)
+                return 2, {"error": str(e)}


+        self.assertEqual(exit_code, 0)
+        self.assertIn("result", result)
+        mock_resolve.assert_called_once_with("PythonTest/Get", "")


+        self.assertEqual(exit_code, 0)
+        self.assertEqual(result["result"][0]["type"], "PythonTest/Get")
+        self.assertEqual(result["name"], "PythonTest/Get")
+        self.assertEqual(result["result"][0]["name"], "PythonTest/Get")
+        mock_resolve.assert_called_once_with("PythonTest/Get", "")


+        self.assertEqual(exit_code, 0)
+        self.assertEqual(result["result"][0]["type"], "PythonTest/Get")
+        self.assertEqual(result["name"], "PythonTest/Get")
+        self.assertEqual(result["result"][0]["name"], "PythonTest/Get")
+        mock_resolve.assert_called_once_with("PythonTest/Get", "")


+                # Python adapter manifest now has a condition on python3 availability.
+                # If unavailable, resource discovery should fail cleanly rather than execution failing.
+                $Result.StdErr | Should -Match "Resource not found:\s*PythonTest/|Failed to parse resource:"


Copilot

Pull request overview

Copilot reviewed 22 out of 28 changed files in this pull request and generated 7 comments.

Comments suppressed due to low confidence (1)

adapters/python/tests/pythonintegration.tests.ps1:25

This comment claims the Python adapter manifest has a condition on python3 availability, but the manifest added in this PR does not include a condition field. This is misleading for future maintainers and for interpreting failure expectations in this helper.

                # Python adapter manifest now has a condition on python3 availability.
                # If unavailable, resource discovery should fail cleanly rather than execution failing.

+    # 1. Start with --input as the authoritative source
+    input_str = args.input
+
+    # 2. If stdin has data, it overrides --input (DSC convention)
+    stdin_data = sys.stdin.read().strip() if not sys.stdin.isatty() else ""
+    if stdin_data:
+        input_str = stdin_data
+


+    "list": {
+      "executable": "python3",
+      "args": [
+        "pyDscAdapter/__main__.py",


+  "get": {
+    "executable": "python3",
+    "args": [
+      "pyDscAdapter/__main__.py",


+  "set": {
+    "executable": "python3",
+    "args": [
+      "pyDscAdapter/__main__.py",


+  "test": {
+    "executable": "python3",
+    "args": [
+      "pyDscAdapter/__main__.py",


+  "export": {
+    "executable": "python3",
+    "args": [
+      "pyDscAdapter/__main__.py",


+  "validate": {
+    "executable": "python3",
+    "args": [
+      "pyDscAdapter/__main__.py",


shammu1 force-pushed the python-adapter-v1 branch 2 times, most recently from 4c04457 to 6ccefc6 Compare May 7, 2026 19:52

shammu1 force-pushed the python-adapter-v1 branch 6 times, most recently from e3b036f to bb93ae9 Compare May 14, 2026 02:21

shammu1 marked this pull request as ready for review May 14, 2026 03:29

Copilot AI review requested due to automatic review settings May 14, 2026 03:29

SteveL-MSFT requested review from Copilot and removed request for Copilot May 15, 2026 17:17

Copilot started reviewing on behalf of SteveL-MSFT May 15, 2026 17:17 View session

Copilot AI reviewed May 15, 2026

View reviewed changes

shammu1 requested a review from Copilot May 21, 2026 16:41

Copilot AI reviewed May 21, 2026

View reviewed changes

shammu1 force-pushed the python-adapter-v1 branch from 88dca5c to cb13bdd Compare June 15, 2026 23:26

shammu1 requested a review from Copilot July 10, 2026 19:55

Copilot started reviewing on behalf of shammu1 July 10, 2026 19:57 View session

Copilot AI reviewed Jul 10, 2026

View reviewed changes

shammu1 requested a review from Copilot July 13, 2026 22:10

Copilot started reviewing on behalf of shammu1 July 13, 2026 22:10 View session

Copilot AI reviewed Jul 13, 2026

View reviewed changes

Shammu Meenakshi Sundaram added 5 commits July 20, 2026 17:14

Python DSC Adapter and Test Resource implementation

d894912

python-adapter-v2

f6b7e86

python-adapter-v3

70438b5

python-adapter-v4

e82c452

python-adapter-v4

173a2d6

python-adapter-v5

7029eb3

Copilot AI review requested due to automatic review settings July 21, 2026 00:15

shammu1 force-pushed the python-adapter-v1 branch from 63a7654 to 7029eb3 Compare July 21, 2026 00:15

Copilot started reviewing on behalf of shammu1 July 21, 2026 00:16 View session

Copilot AI reviewed Jul 21, 2026

View reviewed changes

		@@ -0,0 +1,6 @@
		import sys
		from cli import main # TODO: Currently using absolute imports. Switch to relative imports if this is later used as a module in the adapter manifest; otherwise, keep as-is for direct script execution.

Uh oh!

Conversation

shammu1 commented May 7, 2026

PR Summary

PR Context

Uh oh!

shammu1 commented May 8, 2026

Uh oh!

shammu1 commented May 15, 2026

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Reviewed changes

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants