feat: Beginning to flesh out the interface

changelog/5.feature.md

@@ -0,0 +1,3 @@
+Adds the concept of MetricProvider's and Metrics to the core.
+These represent the functionality that metric providers must implement in order to be part of the REF.
+The implementation is still a work in progress and will be expanding in follow-up PRs.

docs/explanation.md

@@ -12,6 +12,33 @@ Points we will aim to cover:
 We will aim to avoid writing instructions or technical descriptions here,
 they belong elsewhere.
 
+## Metric Providers
+
+The REF aims to support a variety of metric providers.
+These providers are responsible for performing the calculations and analyses.
+
+Each metric provider generally provides a number of different metrics that can be calculated.
+An example implementation of a metric provider is provided in the `ref_metrics_example` package.
+
+### Metrics
+
+A metric represents a specific calculation or analysis that can be performed on a dataset
+or set of datasets with the aim for benchmarking the performance of different models.
+These metrics often represent a specific aspects of the Earth system and are compared against
+observations of the same quantities.
+
+A metric depends upon a set of input model data and observation datasets.
+
+The result of a metric calculation can be a range of different outcomes:
+
+* A single scalar value
+* Timeseries
+* Plots
+
+The Earth System Metrics and Diagnostics Standards
+([EMDS](https://github.com/Earth-System-Diagnostics-Standards/EMDS))
+provide a community standard for reporting outputs.
+This enables the ability to generate standardised outputs that can be distributed.
 
 ## Execution Environments
 

packages/ref-core/pyproject.toml

@@ -21,10 +21,12 @@ classifiers = [
     "Topic :: Scientific/Engineering",
 ]
 dependencies = [
+    "attrs"
 ]
 
 [tool.uv]
 dev-dependencies = [
+
 ]
 
 [build-system]

packages/ref-core/src/ref_core/executor/__init__.py

@@ -13,9 +13,11 @@
 """
 
 import os
-from typing import Protocol, runtime_checkable
+from typing import Any, Protocol, runtime_checkable
 
-from .local import LocalExecutor
+from ref_core.executor.local import LocalExecutor
+from ref_core.metrics import Configuration, Metric, MetricResult, TriggerInfo
+from ref_core.providers import MetricsProvider
 
 
 @runtime_checkable
@@ -33,11 +35,30 @@ class Executor(Protocol):
 
     name: str
 
-    def run_metric(self, metric: object, *args, **kwargs) -> object:  # type: ignore
+    def run_metric(
+        self, metric: Metric, configuration: Configuration, trigger: TriggerInfo | None, **kwargs: Any
+    ) -> MetricResult:
         """
         Execute a metric
+
+        Parameters
+        ----------
+        metric
+            Metric to run
+        configuration
+            Configuration to run the metric with
+        trigger
+            Information about the dataset that triggered the metric run
+
+            TODO: The optionality of this parameter is a placeholder and will be expanded in the future.
+        kwargs
+            Additional keyword arguments for the executor
+
+        Returns
+        -------
+        :
+            Results from running the metric
         """
-        # TODO: Add type hints for metric and return value in follow-up PR
         ...
 
 
@@ -94,7 +115,7 @@ def get(self, name: str) -> Executor:
 get_executor = _default_manager.get
 
 
-def run_metric(metric_name: str, *args, **kwargs) -> object:  # type: ignore
+def run_metric(metric_name: str, /, metrics_provider: MetricsProvider, **kwargs: Any) -> MetricResult:
     """
     Run a metric using the default executor
 
@@ -107,13 +128,10 @@ def run_metric(metric_name: str, *args, **kwargs) -> object:  # type: ignore
     ----------
     metric_name
         Name of the metric to run.
-
-        Eventually the metric will be sourced from via some kind of registry.
-        For now, it's just a placeholder.
-    args
-        Extra arguments passed to the metric of interest
+    metrics_provider
+        Provider from where to retrieve the metric
     kwargs
-        Extra keyword arguments passed to the metric of interest
+        Additional options passed to the metric executor
 
     Returns
     -------
@@ -123,10 +141,14 @@ def run_metric(metric_name: str, *args, **kwargs) -> object:  # type: ignore
     executor_name = os.environ.get("CMIP_REF_EXECUTOR", "local")
 
     executor = get_executor(executor_name)
-    # metric = get_metric(metric_name)  # TODO: Implement this
-    metric = kwargs.pop("metric")
+    metric = metrics_provider.get(metric_name)
+
+    result = executor.run_metric(metric, trigger=None, **kwargs)
+
+    # TODO: Validate the result
+    # TODO: Log the result
 
-    return executor.run_metric(metric, *args, **kwargs)
+    return result
 
 
 register_executor(LocalExecutor())

packages/ref-core/src/ref_core/executor/local.py

@@ -1,3 +1,8 @@
+from typing import Any
+
+from ref_core.metrics import Configuration, Metric, MetricResult, TriggerInfo
+
+
 class LocalExecutor:
     """
     Run a metric locally, in-process.
@@ -9,19 +14,26 @@ class LocalExecutor:
 
     name = "local"
 
-    def run_metric(self, metric, *args, **kwargs):  # type: ignore
+    def run_metric(
+        self, metric: Metric, configuration: Configuration, trigger: TriggerInfo | None, **kwargs: Any
+    ) -> MetricResult:
         """
         Run a metric in process
 
         Parameters
         ----------
         metric
-        args
+            Metric to run
+        configuration
+            Configuration to run the metric with
+        trigger
+            Information about the dataset that triggered the metric run
         kwargs
+            Additional keyword arguments for the executor
 
         Returns
         -------
         :
             Results from running the metric
         """
-        return metric.run(*args, **kwargs)
+        return metric.run(configuration=configuration, trigger=trigger)

packages/ref-core/src/ref_core/metrics.py

@@ -0,0 +1,144 @@
+import json
+import pathlib
+from typing import Any, Protocol, runtime_checkable
+
+from attrs import frozen
+
+
+@frozen
+class Configuration:
+    """
+    Configuration that describes the input data sources
+    """
+
+    output_directory: pathlib.Path
+    """
+    Directory to write output files to
+    """
+
+    # TODO: Add more configuration options here
+
+
+@frozen
+class MetricResult:
+    """
+    The result of running a metric.
+
+    The content of the result follows the Earth System Metrics and Diagnostics Standards
+    ([EMDS](https://github.com/Earth-System-Diagnostics-Standards/EMDS/blob/main/standards.md)).
+    """
+
+    # Do we want to load a serialised version of the output bundle here or just a file path?
+
+    output_bundle: pathlib.Path | None
+    """
+    Path to the output bundle file.
+
+    The contents of this file are defined by
+    [EMDS standard](https://github.com/Earth-System-Diagnostics-Standards/EMDS/blob/main/standards.md#common-output-bundle-format-)
+    """
+    successful: bool
+    """
+    Whether the metric ran successfully.
+    """
+    # Log info is in the output bundle file already, but is definitely useful
+
+    @staticmethod
+    def build(configuration: Configuration, cmec_output_bundle: dict[str, Any]) -> "MetricResult":
+        """
+        Build a MetricResult from a CMEC output bundle.
+
+        Parameters
+        ----------
+        configuration
+            The configuration used to run the metric.
+        cmec_output_bundle
+            An output bundle in the CMEC format.
+
+            TODO: This needs a better type hint
+
+        Returns
+        -------
+        :
+            A prepared MetricResult object.
+            The output bundle will be written to the output directory.
+        """
+        with open(configuration.output_directory / "output.json", "w") as file_handle:
+            json.dump(cmec_output_bundle, file_handle)
+        return MetricResult(
+            output_bundle=configuration.output_directory / "output.json",
+            successful=True,
+        )
+
+
+@frozen
+class TriggerInfo:
+    """
+    The reason why the metric was run.
+    """
+
+    dataset: pathlib.Path
+    """
+    Path to the dataset that triggered the metric run.
+    """
+
+    # TODO:
+    # Add/remove/modified?
+    # dataset metadata
+
+
+@runtime_checkable
+class Metric(Protocol):
+    """
+    Interface for the calculation of a metric.
+
+    This is a very high-level interface to provide maximum scope for the metrics packages
+    to have differing assumptions.
+    The configuration and output of the metric should follow the
+    Earth System Metrics and Diagnostics Standards formats as much as possible.
+
+    See (ref_example.example.ExampleMetric)[] for an example implementation.
+    """
+
+    name: str
+    """
+    Name of the metric being run
+
+    This should be unique for a given provider,
+    but multiple providers can implement the same metric.
+    """
+
+    # input_variable: list[VariableDefinition]
+    """
+    TODO: implement VariableDefinition
+    Should be extend the configuration defined in EMDS
+
+    Variables that the metric requires to run
+    Any modifications to the input data will trigger a new metric calculation.
+    """
+    # observation_dataset: list[ObservationDatasetDefinition]
+    """
+    TODO: implement ObservationDatasetDefinition
+    Should be extend the configuration defined in EMDS. To check with Bouwe.
+    """
+
+    def run(self, configuration: Configuration, trigger: TriggerInfo | None) -> MetricResult:
+        """
+        Run the metric on the given configuration.
+
+        The implementation of this method method is left to the metrics providers.
+
+        A CMEC-compatible package can use: TODO: Add link to CMEC metric wrapper
+
+        Parameters
+        ----------
+        configuration : Configuration
+            The configuration to run the metric on.
+        trigger : TriggerInfo | None
+            Optional information about the dataset that triggered the metric run.
+
+        Returns
+        -------
+        MetricResult
+            The result of running the metric.
+        """

packages/ref-core/src/ref_core/providers.py

@@ -0,0 +1,58 @@
+"""
+Interfaces for metrics providers.
+
+This defines how metrics packages interoperate with the REF framework.
+"""
+
+from ref_core.metrics import Metric
+
+
+class MetricsProvider:
+    """
+    Interface for that a metrics provider must implement.
+
+    This provides a consistent interface to multiple different metrics packages.
+    """
+
+    def __init__(self, name: str, version: str) -> None:
+        self.name = name
+        self.version = version
+
+        self._metrics: dict[str, Metric] = {}
+
+    def __len__(self) -> int:
+        return len(self._metrics)
+
+    def register(self, metric: Metric) -> None:
+        """
+        Register a metric with the manager.
+
+        Parameters
+        ----------
+        metric : Metric
+            The metric to register.
+        """
+        if not isinstance(metric, Metric):
+            raise ValueError("Metric must be an instance of Metric")
+        self._metrics[metric.name.lower()] = metric
+
+    def get(self, name: str) -> Metric:
+        """
+        Get a metric by name.
+
+        Parameters
+        ----------
+        name : str
+            Name of the metric (case-sensitive).
+
+        Raises
+        ------
+        KeyError
+            If the metric with the given name is not found.
+
+        Returns
+        -------
+        Metric
+            The requested metric.
+        """
+        return self._metrics[name.lower()]