[core/plugins] Add `PluginLoader`, `SubmitterProvider`, and `config.json` name/version resolution by gregoire-dl · Pull Request #3171 · alicevision/Meshroom

gregoire-dl · 2026-07-15T23:42:35Z

Description

Introduce a new PluginLoader and a redesigned PluginManager. Change previous in code definition of a plugin (e.g. a package / subfolder of a meshroom folder). A plugin is now a folder with a meshroom subfolder possibly containing multiple standalone node description modules, submitter modules, templates and a configuration file.

Plugin:

Store for each plugin the name, version, type (BUILTIN / PATH / REZ), templates, configuration and also the:

NodeDescProvider objects (node description class with validity status and loading errors)
SubmitterProvider objects (submitter instance with validity status and loading errors)

PluginLoader:

Load/Unload plugin python modules / packages into a common virtual package following this pattern:

_meshroomPlugins.<PluginName>.<PluginSubFolder>.<Module>
_meshroomPlugins.<PluginName>.<PluginSubPkg>.<Module>
_meshroomPlugins.<PluginName>.<Module>

PluginName is defined from the REZ package name, the config.json file or in the last case the folder name of the plugin.
This pattern helps to prevent collision in plugin modules and replaces the previous Plugin.uid. The Loader ensures that only one plugin loaded with PluginName can be used (the first). All issues in the loading process are logged in a summary for each plugin loaded. Also, the loading mechanism has been updated to add support for new plugin layouts with standalone node description files and also submitter files inside the plugin.

Plugins with standalone node files are now supported (no __init__.py):

├── customPlugin/ 
│   ├── meshroom/
│   │   ├── customNodes1/
│   │   │   ├── NodeA.py
│   │   │   ├── NodeB.py
│   └── ...

Plugins without subfolders are now supported:

├── customPlugin/ 
│   ├── meshroom/
│   │   ├── NodeA.py
│   │   ├── NodeB.py
│   └── ...

Plugins with node descriptions and/or submitters:

├── customPlugin/ 
│   ├── meshroom/
│   │   ├── customNodes/
│   │   │   ├── NodeA.py
│   │   │   ├── NodeB.py
│   │   ├── customSubmitter/
│   │   │   ├── SubmitterA.py
│   └── ...

PluginManager:

Manage plugins and register node description classes and now submitter instances.
Following the previous implementation, this object centralizes all loaded plugins, available node descriptions and submitters.
The PluginManager now provides simple methods for online plugin loading:

addPluginFromRez for a plugin provided with REZ
addPluginFromPath for a plugin located at an arbitrary path
addPluginFromBuiltInFolder for a plugin folder using Meshroom environment (e.g. meshroom/nodes)

Unit tests:

All unit tests have been updated to follow these changes.
Multiple have been added for the new PluginLoader.

Backward Compatibility:

Fully backward-compatible, previous plugin structures and configurations remain supported.

Implementation remarks

config.json can now be written in two formats:

A plain list of environment variable entries:

[
    { "key": "MY_VAR", "type": "string", "value": "myValue" },
    { "key": "MY_PATH", "type": "path", "value": "relativeOrAbsolutePath" }
]

An object with optional name, version, and env keys, env using the same entry format as above:

{
    "name": "customPlugin",
    "version": "1.0.0",
    "env": [
        { "key": "MY_VAR", "type": "string", "value": "myValue" }
    ]
}

Break the monolithic `core/plugins.py` module into focused submodules under `core/plugins`: - `env.py`: ProcessEnvType, ProcessEnv, DirTreeProcessEnv, RezProcessEnv, and processEnvFactory (process-environment resolution for plugin execution) - `base.py`: Plugin, NodePlugin, NodePluginStatus, validateNodeDesc, formatNodeDescriptionErrorMessage - `manager.py`: NodePluginManager Update all call sites to import from the new submodules.

Change terminology for methods, function and variables. Update all call sites and documentation.

…eDescProvider.nodeDescClass`

…onErrorMessage` inside `NodeDescProvider`

…eDesc`

…input type

…d type

…atus`

…der`

…n `Plugin`

…nLoader` Delete the `loadClasses` based discovery pipeline from `meshroom/core/__init__.py` (`add_to_path`, `loadClasses(Nodes|Submitters)`, `loadAllNodes`, `loadPluginFolder`, `registerSubmitter`, `loadAllSubmitters`, `initRezPlugins`), and rewrite `initNodes`/`initSubmitters`/`initPlugins` to go through `PluginManager.addPluginFromBuiltInFolder`/`addPluginFromPath`/`addPluginFromRez` instead. `PluginManager` now owns a `PluginLoader` and registers the providers a `Plugin` contains via `registerPluginProviders`, replacing the old `addPlugin`/`registerNode`/ `unregisterNode`. An invalid or name-colliding node/submitter provider is skipped without failing the whole plugin load. `Plugin` now carries its own `PluginType` and builds its own `ProcessEnv` (dirtree or rez) at construction. `NodeDescProvider`/`SubmitterProvider` gain `absolutePackage`/ `relativePackage` so a node's process environment (and Rez subrequires) can be resolved per sub-package within a plugin, not just per plugin. Port every test off the removed functions onto the new `PluginManager`/`PluginLoader` API, and flatten the test plugin fixtures from `tests/plugins/meshroom/<name>/` to `tests/plugins/<name>/meshroom/`, matching the new one-folder-per-plugin model.

…sion

This allows to have a proper name for each built-in plugin, the name of the subfolder of the given node folder.

…ion file

gregoire-dl · 2026-07-16T09:24:50Z

+            bool: True if the node descriptor provider has successfully been reloaded (i.e. there was
+                  no error, and some changes were made since its last loading), False otherwise.
+        """
+        timestamp = 0.0


This PR should not modify this method code logic.

codecov · 2026-07-15T23:44:11Z

Codecov Report

❌ Patch coverage is 86.88525% with 152 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.54%. Comparing base (1d89d80) to head (cf1bd6c).
⚠️ Report is 2 commits behind head on develop.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
meshroom/core/plugins/env.py	55.75%	50 Missing ⚠️
meshroom/core/plugins/base.py	87.02%	34 Missing ⚠️
meshroom/core/__init__.py	30.00%	21 Missing ⚠️
meshroom/core/plugins/config.py	74.64%	18 Missing ⚠️
meshroom/core/plugins/loader.py	90.32%	15 Missing ⚠️
meshroom/core/plugins/manager.py	85.26%	14 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #3171      +/-   ##
===========================================
+ Coverage    86.07%   86.54%   +0.46%     
===========================================
  Files           78       83       +5     
  Lines        12111    12400     +289     
===========================================
+ Hits         10425    10731     +306     
+ Misses        1686     1669      -17

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

gemini-code-assist

Code Review

This pull request refactors Meshroom's plugin loading and management system, replacing the old NodePlugin architecture with a more modular design centered around PluginManager, PluginLoader, NodeDescProvider, and SubmitterProvider. While this refactoring significantly improves plugin isolation and environment handling (including Rez and DirTree environments), several critical issues must be addressed. First, numerous invalid dictionary type hints use colons instead of commas (e.g., dict[str: str]), which will cause runtime errors. Second, splitting Rez package names with partition('-') will fail for package names containing hyphens; rpartition('-') should be used instead. Third, potential AttributeError and TypeError exceptions exist when reloading missing modules or accessing unassigned providers. Finally, file operations should explicitly specify utf-8 encoding to prevent Windows-specific decode errors, and environment path constructions must be guarded against trailing separators to avoid importing from the current working directory.

Important

The consumer version of Gemini Code Assist on GitHub is being sunset. Starting June 18, 2026, new organization installations will be blocked, and all code review activity will officially cease on July 17, 2026.
For more details on the timeline and next steps, please review the Help Documentation.

gemini-code-assist · 2026-07-15T23:46:06Z

+        self._env["PYTHONPATH"] = os.pathsep.join(
+            [f"{_MESHROOM_ROOT}"] + self.pythonPaths + [os.getenv('PYTHONPATH', '')])


If os.getenv('PYTHONPATH') is empty or not set, appending "" to the path list and joining with os.pathsep will result in a trailing path separator. In Python/Linux, a trailing separator represents the current working directory (.), which can lead to unexpected module imports or security risks. It is safer to filter out empty paths.

Suggested change

self._env["PYTHONPATH"] = os.pathsep.join(

[f"{_MESHROOM_ROOT}"] + self.pythonPaths + [os.getenv('PYTHONPATH', '')])

pythonPaths = [f"{_MESHROOM_ROOT}"] + self.pythonPaths

envPythonPath = os.getenv('PYTHONPATH')

if envPythonPath:

pythonPaths.append(envPythonPath)

self._env["PYTHONPATH"] = os.pathsep.join(pythonPaths)

gemini-code-assist · 2026-07-15T23:46:06Z

+            return False
+
+        try:
+            updated = importlib.reload(sys.modules.get(self.nodeDescClass.__module__))


sys.modules.get(...) can return None if the module is not currently loaded or registered in sys.modules. Passing None to importlib.reload() will raise a TypeError. It is safer to guard against None before reloading.

Suggested change

updated = importlib.reload(sys.modules.get(self.nodeDescClass.__module__))

module = sys.modules.get(self.nodeDescClass.__module__)

if module is None:

self.status = NodeDescProviderStatus.ERROR

logging.error(f"[Reload] {self.name}: The module {self.nodeDescClass.__module__} was not found in sys.modules.")

return False

try:

updated = importlib.reload(module)

gemini-code-assist · 2026-07-15T23:46:06Z

    def processChunk(self, chunk):
        cmd = self.buildCommandLine(chunk)
-        runtimeEnv = chunk.node.nodeDesc.plugin.runtimeEnv
+        runtimeEnv = chunk.node.nodeDesc.provider.runtimeEnv


If provider is None (e.g., if the node descriptor is instantiated directly without being registered via a NodeDescProvider), accessing provider.runtimeEnv will raise an AttributeError. Adding a defensive check prevents potential crashes.

Suggested change

runtimeEnv = chunk.node.nodeDesc.provider.runtimeEnv

runtimeEnv = chunk.node.nodeDesc.provider.runtimeEnv if chunk.node.nodeDesc.provider else None

gemini-code-assist · 2026-07-15T23:46:06Z

-        runtimeEnv = chunk.node.nodeDesc.plugin.runtimeEnv
-        cmdPrefix = chunk.node.nodeDesc.plugin.commandPrefix
-        cmdSuffix = chunk.node.nodeDesc.plugin.commandSuffix
+        runtimeEnv = chunk.node.nodeDesc.provider.runtimeEnv


If provider is None (e.g., if the node descriptor is instantiated directly without being registered via a NodeDescProvider), accessing provider.runtimeEnv will raise an AttributeError. Adding a defensive check prevents potential crashes.

Suggested change

runtimeEnv = chunk.node.nodeDesc.provider.runtimeEnv

runtimeEnv = chunk.node.nodeDesc.provider.runtimeEnv if chunk.node.nodeDesc.provider else None

…cProviders`

gregoire-dl added 28 commits July 14, 2026 14:03

[core/plugins] Manager: Rename NodePluginManager to PluginManager

bf15092

[core/plugins] Base: Rename NodePlugin to NodeDescProvider

d1fa49a

Change terminology for methods, function and variables. Update all call sites and documentation.

[core/plugins] Base: Rename NodeDescProvider.nodeDescriptor to `Nod…

9cf0ae8

…eDescProvider.nodeDescClass`

[core/plugins] Base: Move validateNodeDesc and `formatNodeDescripti…

76f6445

…onErrorMessage` inside `NodeDescProvider`

[core/plugins] Base: Remove isUserPlugin in NodeDescProvider

b5452b4

[core/plugins] Manager: Rename isRegistered to isNodeDescRegistered

675db36

[core/plugins] Manager: Rename belongsToPlugin to `getPluginFromNod…

183a656

…eDesc`

[core/plugins] Base: Fix reloadmissing plugin and trailing-whitespaces

a7e0168

[core/plugins] Base: Rename __validateNodeDescClass method and fix …

a4a6405

…input type

[core/plugins] Base: Fix NodeDescProvider constructor input name an…

f361572

…d type

[core/plugins] Base: Add PluginType enum

bc2801e

[core/plugins] Base: Add SubmitterProvider and `SubmitterProviderSt…

d7f9924

…atus`

[core/plugins] Add SubmitterProvider in Plugin and PluginManager

ce3ed44

[core/plugins] Base: Rename self._isUserPlugin in Plugin

11e01c0

[core/plugins] Base: Use _name as identifier for `addSubmitterProvi…

68dd593

…der`

[core/plugins] Base: Add name property to NodeDescProvider

8d809ab

[core/plugins] Base: Rename nodes property to nodeDescProviders i…

3e50d0a

…n `Plugin`

[core/plugins] Add PluginLoader

9446e7e

[tests] Add test file for PluginLoader

7e4cffe

[core/plugins] Base: Fix Plugin folder path for processEnvFactory

edaabf8

[core/plugins] Base: Add version for Plugin

645b144

[core/plugins] Add PluginConfig

00365d0

[core/plugins] Loader: Use PluginConfig to find plugin name and ver…

68d3c11

…sion

[tests] pluginLoader: Add tests for PluginConfig

8c42af3

[core] Init: Load subfolders as built-in plugins

4a5fcee

This allows to have a proper name for each built-in plugin, the name of the subfolder of the given node folder.

[doc] Update INSTALL_PLUGINS.md for standalone nodes and configurat…

94e90eb

…ion file

gregoire-dl added this to the Meshroom 2026.1.0 milestone Jul 15, 2026

gregoire-dl self-assigned this Jul 15, 2026

gregoire-dl added the type:enhancement label Jul 15, 2026

github-code-quality Bot found potential problems Jul 15, 2026

View reviewed changes

gemini-code-assist Bot reviewed Jul 15, 2026

View reviewed changes

gregoire-dl added 3 commits July 16, 2026 10:58

[tests] Add missing config.json for test plugin pluginA

6a5c0d2

[core/plugins] Base / Env / Manager: Fix dict type hints

151cc83

[tests] Utils: use utf-8 encoding in writeFile

1d6c845

gregoire-dl marked this pull request as ready for review July 16, 2026 09:28

gregoire-dl requested review from Alxiice, cbentejac and fabiencastan July 16, 2026 09:28

gregoire-dl added 5 commits July 16, 2026 11:45

[core/plugins] Manager: Fix PluginManager docstring

ce88202

[core/plugins] Base: Fix Plugin docstring

94cd2b1

[core] Init: Fix update pipeline templates in initPlugins()

6e8e0d8

[core/plugins] Base/Loader/Manager: Improve logs

4ed9af9

[core/plugins] Base: Reuse Plugin's processEnv for dirtree `NodeDes…

cf1bd6c

…cProviders`

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Uh oh!

[core/plugins] Add `PluginLoader`, `SubmitterProvider`, and `config.json` name/version resolution#3171

[core/plugins] Add `PluginLoader`, `SubmitterProvider`, and `config.json` name/version resolution#3171
gregoire-dl wants to merge 36 commits into
developfrom
dev/enhancePluginManager

gregoire-dl commented Jul 15, 2026 •

edited

Loading

Uh oh!

gregoire-dl Jul 16, 2026

Uh oh!

codecov Bot commented Jul 15, 2026 •

edited

Loading

Uh oh!

gemini-code-assist Bot left a comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

gemini-code-assist Bot Jul 15, 2026

Uh oh!

gemini-code-assist Bot Jul 15, 2026

Uh oh!

gemini-code-assist Bot Jul 15, 2026

Uh oh!

gemini-code-assist Bot Jul 15, 2026

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

1 participant

		self._env["PYTHONPATH"] = os.pathsep.join(
		[f"{_MESHROOM_ROOT}"] + self.pythonPaths + [os.getenv('PYTHONPATH', '')])

-        self._env["PYTHONPATH"] = os.pathsep.join(
-            [f"{_MESHROOM_ROOT}"] + self.pythonPaths + [os.getenv('PYTHONPATH', '')])
+        pythonPaths = [f"{_MESHROOM_ROOT}"] + self.pythonPaths
+        envPythonPath = os.getenv('PYTHONPATH')
+        if envPythonPath:
+            pythonPaths.append(envPythonPath)
+        self._env["PYTHONPATH"] = os.pathsep.join(pythonPaths)

-            updated = importlib.reload(sys.modules.get(self.nodeDescClass.__module__))
+        module = sys.modules.get(self.nodeDescClass.__module__)
+        if module is None:
+            self.status = NodeDescProviderStatus.ERROR
+            logging.error(f"[Reload] {self.name}: The module {self.nodeDescClass.__module__} was not found in sys.modules.")
+            return False
+        try:
+            updated = importlib.reload(module)

	runtimeEnv = chunk.node.nodeDesc.provider.runtimeEnv
	runtimeEnv = chunk.node.nodeDesc.provider.runtimeEnv if chunk.node.nodeDesc.provider else None

Uh oh!

Uh oh!

Conversation

gregoire-dl commented Jul 15, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Description

Implementation remarks

Uh oh!

gregoire-dl Jul 16, 2026

Choose a reason for hiding this comment

Uh oh!

codecov Bot commented Jul 15, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Codecov Report

Uh oh!

gemini-code-assist Bot left a comment

Choose a reason for hiding this comment

Code Review

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

gemini-code-assist Bot Jul 15, 2026

Choose a reason for hiding this comment

Uh oh!

gemini-code-assist Bot Jul 15, 2026

Choose a reason for hiding this comment

Uh oh!

gemini-code-assist Bot Jul 15, 2026

Choose a reason for hiding this comment

Uh oh!

gemini-code-assist Bot Jul 15, 2026

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

1 participant

gregoire-dl commented Jul 15, 2026 •

edited

Loading

codecov Bot commented Jul 15, 2026 •

edited

Loading