Add JSON output writer and Hydra output=json config

[izzet]

This pull request adds support for exporting analysis results in JSON format, including configuration, implementation, and end-to-end tests. The changes introduce a new JSONOutput class, update configuration and type definitions to support the new output type, and document the new feature for users.

JSON Output Feature

• Added a new JSONOutput class to python/dftracer/analyzer/output.py that saves analysis results as a structured JSON file, including raw stats, per-view summaries, per-layer metrics, and additional metric statistics. The output file path is configurable.
• Created a corresponding JSONOutputConfig dataclass in python/dftracer/analyzer/config.py and registered it with Hydra's config store, enabling users to select JSON output via configuration. [1] [2]

Type and Import Updates

• Updated the OutputType union and imports in python/dftracer/analyzer/__init__.py to include JSONOutput, ensuring proper typing and discoverability. [1] [2]

Documentation

• Added documentation for JSON output in docs/configuration.rst, describing its contents, configuration parameters, and default behavior.

Testing

• Added an end-to-end test in tests/test_e2e.py to verify that JSON output is correctly produced, contains expected fields, and is written to the specified file path. [1] [2]

[Copilot]

Pull request overview

This PR adds JSON output support to the DFAnalyzer tool, allowing users to export analysis results as structured JSON files instead of (or in addition to) the default console output. It includes a new JSONOutput class, a corresponding Hydra configuration dataclass, updated type exports, documentation, and an end-to-end test.

Changes:

• Introduces JSONOutput class and JSONOutputConfig dataclass, registered with Hydra's config store under output=json
• Refactors _additional_metric_scale_and_unit from ConsoleOutput up to the base Output class so it can be shared with JSONOutput
• Adds an end-to-end smoke test validating JSON file creation and schema structure

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
python/dftracer/analyzer/output.py	Adds JSONOutput class with handle_result, _create_raw_stats, _create_summary_payload, _create_additional_metrics_payload, _resolve_output_path; moves _additional_metric_scale_and_unit to base Output class
python/dftracer/analyzer/config.py	Adds JSONOutputConfig dataclass and registers it with Hydra config store
python/dftracer/analyzer/__init__.py	Imports and exports JSONOutput, adds it to OutputType union
tests/test_e2e.py	Adds test_json_output_file smoke test verifying JSON output creation and schema
docs/configuration.rst	Documents JSON output parameters and default behavior

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