Feat: registry (backends / transports / schedulers)

docs/user/reference/api.md

@@ -11,6 +11,14 @@ Anything else, including every name starting with `_`, is internal.
 
 ::: intercede.models
 
+## Configuration
+
+::: intercede.config
+
+## Registry
+
+::: intercede.registry
+
 ## Exceptions
 
 ::: intercede.exceptions

mkdocs.yml

@@ -17,6 +17,12 @@ plugins:
             show_source: false
             members_order: source
             merge_init_into_class: true
+            inherited_members: true
+            # Field tables for the configuration models, read from the models
+            # themselves, so the documentation cannot drift from the code.
+            extensions:
+              - griffe_pydantic:
+                  schema: false
 
 validation:
   links:

pyproject.toml

@@ -100,6 +100,9 @@ ignore = [
   "FLY002",
 ]
 
+[tool.ruff.lint.pydocstyle]
+convention = "google"
+
 [tool.ruff.lint.isort]
 required-imports = ["from __future__ import annotations"]
 
@@ -144,6 +147,7 @@ intercede = { path = ".", editable = true }
 mkdocs = "<2"
 mkdocs-material = "*"
 mkdocstrings = { version = "*", extras = ["python"] }
+griffe-pydantic = "*"
 [tool.pixi.feature.docs.tasks]
 docs = { cmd = "mkdocs build --strict", description = "Build the documentation" }
 

src/intercede/__init__.py

@@ -5,10 +5,21 @@
 from importlib.metadata import PackageNotFoundError
 from importlib.metadata import version as get_version
 
+from intercede import registry
+from intercede.config import (
+    ARCConfig,
+    BackendConfig,
+    BatchLocalConfig,
+    BatchSSHConfig,
+    CloudConfig,
+    HTCondorCEConfig,
+    validate_config,
+)
 from intercede.exceptions import (
     AuthenticationError,
     ConfigurationError,
     InterCEdeError,
+    RegistryError,
     ResourceUnavailableError,
     SpecificationRejectedError,
 )
@@ -47,6 +58,7 @@
 
 __all__ = [
     "__version__",
+    "registry",
     # protocols
     "Diagnosable",
     "JobBackend",
@@ -71,10 +83,19 @@
     "StatusMap",
     "Submission",
     "SubmissionSpec",
+    # configuration
+    "ARCConfig",
+    "BackendConfig",
+    "BatchLocalConfig",
+    "BatchSSHConfig",
+    "CloudConfig",
+    "HTCondorCEConfig",
+    "validate_config",
     # exceptions
     "AuthenticationError",
     "ConfigurationError",
     "InterCEdeError",
+    "RegistryError",
     "ResourceUnavailableError",
     "SpecificationRejectedError",
 ]

src/intercede/_backends/config.py

@@ -0,0 +1,18 @@
+"""Settings of the in-memory fake, which no public configuration reaches.
+
+Every other backend is built from its public configuration model in
+``intercede.config``.
+"""
+
+from __future__ import annotations
+
+from typing import Literal
+
+from intercede.models import _Model
+
+
+class FakeConfig(_Model):
+    """The in-memory fake, for the test suites."""
+
+    kind: Literal["fake"] = "fake"
+    resource: str = "fake://local"

src/intercede/_backends/fake.py

@@ -6,12 +6,13 @@
 
 from __future__ import annotations
 
-from collections.abc import Collection, Mapping, Sequence
+from collections.abc import Callable, Collection, Mapping, Sequence
 from dataclasses import dataclass, field
 from pathlib import Path
 from types import TracebackType
 from typing import Self
 
+from intercede._backends.config import FakeConfig
 from intercede.exceptions import (
     InterCEdeError,
     ResourceUnavailableError,
@@ -92,6 +93,18 @@ def __init__(
         self._next_id = 0
         self._closed = False
 
+    @classmethod
+    def from_settings(cls, settings: FakeConfig) -> Self:
+        """Build the fake from its settings; how the registry constructs it.
+
+        Args:
+            settings: The fake's settings: only the resource it reports.
+
+        Returns:
+            A new fake, not yet opened.
+        """
+        return cls(resource=settings.resource)
+
     # -- lifecycle ---------------------------------------------------------
 
     async def __aenter__(self) -> Self:
@@ -252,10 +265,8 @@ def _check_supported(self, spec: SubmissionSpec) -> None:
 
         if not self.resource_staging:
             self._check_can_fetch(spec.inputs)
-            if spec.outputs is not None:
+            if spec.outputs is not None:  # no outputs means nothing to upload
                 self._check_can_upload(spec.outputs.members)
-            else:
-                raise SpecificationRejectedError(f"tag: {spec.tag} contains no outputs")
 
     def _check_container_support(self, spec: SubmissionSpec) -> None:
         if spec.container is not None and not self.containers:
@@ -368,3 +379,4 @@ def _write_job_files(
 _kill: type[Killable] = FakeBackend
 _purge: type[Purgeable] = FakeBackend
 _diag: type[Diagnosable] = FakeBackend
+_built_by_registry: Callable[[FakeConfig], JobBackend] = FakeBackend.from_settings