[OSSIE][NVIDIA_GSF] Add bidirectional GSF semantic model converter

converters/README.md

@@ -75,6 +75,7 @@ The Ossie specification currently defines extensions for the following vendors:
 | `DATABRICKS` | Databricks semantic layer |
 | `OMNI` | Omni semantic model |
 | `WISDOM` | WisdomAI domain |
+| `NVIDIA_GSF` | NVIDIA Generative Semantic Fabric standalone YAML |
 
 Each vendor may define custom extensions (via the `custom_extensions` field in the Ossie spec) to carry vendor-specific metadata that does not have an equivalent in the core specification.
 

converters/gsf/README.md

@@ -0,0 +1,131 @@
+<!--
+  Licensed to the Apache Software Foundation (ASF) under one
+  or more contributor license agreements.  See the NOTICE file
+  distributed with this work for additional information
+  regarding copyright ownership.  The ASF licenses this file
+  to you under the Apache License, Version 2.0 (the
+  "License"); you may not use this file except in compliance
+  with the License.  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing,
+  software distributed under the License is distributed on an
+  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+  KIND, either express or implied.  See the License for the
+  specific language governing permissions and limitations
+  under the License.
+-->
+
+# Apache Ossie ↔ NVIDIA GSF Converter
+
+Offline conversion between Apache Ossie YAML and the standalone semantic-model
+YAML format supported by [NVIDIA GSF](https://github.com/NVIDIA/GSF). No GSF,
+Neo4j, database, or network connection is required.
+
+## Mapping
+
+| Apache Ossie | Standalone GSF YAML |
+|---|---|
+| Semantic model | `model` |
+| Dataset | `terms[]` |
+| Physical field | `column_attributes[]` |
+| Computed field | `sql_attributes[]` with `kind: field` |
+| Metric | `sql_attributes[]` with `kind: metric` |
+| Relationship | `semantic_foreign_keys[]` |
+| Expression dialects | `expressions[]` |
+| Dataset source | Term `source` mapping |
+
+Computed fields and metrics include generated full SQL and explicit
+`table_refs`, which lets GSF validate and attach them to its ingested catalog.
+
+## Setup
+
+```bash
+cd converters/gsf
+uv sync
+```
+
+## Ossie → GSF
+
+```bash
+uv run ossie-gsf export \
+  --input ../../examples/tpcds_semantic_model.yaml \
+  --output tpcds.gsf.yaml \
+  --database-name tpcds
+```
+
+`--database-name` supplies the database for sources written as `schema.table`.
+Fully qualified `database.schema.table` sources do not require it.
+
+Python:
+
+```python
+from ossie_gsf import convert_ossie_to_gsf
+
+gsf_yaml = convert_ossie_to_gsf(
+    ossie_yaml,
+    database_name="tpcds",
+)
+```
+
+## GSF → Ossie
+
+```bash
+uv run ossie-gsf import \
+  --input tpcds.gsf.yaml \
+  --output semantic_model.yaml
+```
+
+Use `--name` to override the exported Ossie semantic-model name.
+
+Python:
+
+```python
+from ossie_gsf import convert_gsf_to_ossie
+
+ossie_yaml = convert_gsf_to_ossie(gsf_yaml)
+```
+
+## Loading the converted model into GSF
+
+Run the native GSF importer from the GSF repository:
+
+```bash
+uv run python -m gsf.semantic import \
+  --database-name tpcds \
+  --input tpcds.gsf.yaml
+```
+
+GSF resolves the file against its existing catalog, writes the graph
+transactionally, validates SQL, and refreshes semantic embeddings.
+
+## Conversion behavior and limitations
+
+- Apache Ossie `0.2.0.dev0` and GSF model-file `1.0` are supported.
+- One semantic model is converted per document.
+- GSF term sources must resolve to physical `database.schema.table` names.
+- Simple field expressions become `ColumnAttribute` mappings. Other field
+  expressions become SQL attributes.
+- Multi-dataset metric SQL is joined through declared Ossie relationships.
+  Disconnected datasets fail conversion instead of producing a cross join.
+- GSF SQL attribute names are global, so duplicate computed-field or metric
+  names fail conversion.
+- Native GSF SQL attributes with `kind: attribute` have no unambiguous Ossie
+  field/metric equivalent and fail GSF → Ossie conversion.
+- Metrics are attached to the first referenced dataset. Unqualified metrics in
+  multi-dataset models need an `NVIDIA_GSF` custom extension containing
+  `{"term": "dataset_name"}`.
+- Expression dialect variants are preserved in the standalone GSF file.
+- Ossie custom extensions and GSF metadata are preserved through metadata and
+  `NVIDIA_GSF` custom-extension payloads.
+
+## Tests
+
+```bash
+uv run pytest
+```
+
+The suite includes a checked-in Ossie/GSF fixture pair, bidirectional
+round-trip checks, validation failures, CLI coverage, and verification of
+generated Ossie YAML with the repository's official validator.

converters/gsf/pyproject.toml

@@ -0,0 +1,63 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[dependency-groups]
+dev = [
+    "jsonschema>=4.26.0",
+    "pytest>=8.0",
+    "sqlglot>=30.12.0",
+]
+
+[project]
+name = "apache-ossie-gsf"
+version = "0.1.0.dev0"
+description = "NVIDIA GSF <> Apache Ossie offline YAML converter"
+authors = [{ name = "Apache Software Foundation", email = "dev@ossie.apache.org" }]
+requires-python = ">=3.11"
+readme = "README.md"
+license = "Apache-2.0"
+keywords = [
+    "Apache Ossie",
+    "Ossie",
+    "Open Semantic Interchange",
+    "NVIDIA GSF",
+    "semantic model",
+]
+dependencies = [
+    "PyYAML>=6.0",
+]
+
+[project.scripts]
+ossie-gsf = "ossie_gsf.converter:main"
+
+[project.urls]
+homepage = "https://ossie.apache.org/"
+repository = "https://github.com/apache/ossie/"
+
+[tool.hatch.build.targets.wheel]
+packages = ["src/ossie_gsf"]
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+
+[tool.uv]
+required-version = ">=0.9.0"
+default-groups = ["dev"]

converters/gsf/src/ossie_gsf/__init__.py

@@ -0,0 +1,30 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+"""Bidirectional Apache Ossie and NVIDIA GSF converter."""
+
+from .converter import (
+    GSFConversionError,
+    convert_gsf_to_ossie,
+    convert_ossie_to_gsf,
+)
+
+__all__ = [
+    "GSFConversionError",
+    "convert_gsf_to_ossie",
+    "convert_ossie_to_gsf",
+]