Create new aboutcode.federated library #747

aboutcode/federated/CHANGELOG.rst

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+Changelog
+=============
+
+
+v0.1.0 (October 20, 2025)
+---------------------------
+
+- Initial release of the ``aboutcode.federated`` library based on
+  original work in the ``aboutcode.hashid`` library.

aboutcode/federated/README.rst

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+aboutcode.federated
+===================
+
+This is a library of utilities to compute ids and file paths for AboutCode
+federated data based on Package URL
+
+
+Federated data utilities goal is to handle content-defined and hash-addressable
+Package data keyed by PURL stored in many Git repositories. This approach to
+federate decentralized data is called FederatedCode.
+
+
+Overview
+========
+
+The main design elements for these utilities are:
+
+1. **Data Federation**: A Data Federation is a database, representing a consistent,
+non-overlapping set of data kind clusters (like scans, vulnerabilities or SBOMs)
+across many package ecosystems, aka. PURL types.
+A Federation is similar to a traditional database.
+
+2. **Data Cluster**: A Data Federation contains Data Clusters, where a Data Cluster
+purpose is to store the data of a single kind (like scans) across multiple PURL
+types. The cluster name is the data kind name and is used as the prefix for
+repository names. A Data Cluster is akin to a table in a traditional database.
+
+3. **Data Repository**: A DataCluster contains of one or more Git Data Repository,
+each storing datafiles of the cluster data kind and a one PURL type, spreading
+the datafiles in multiple Data Directories. The name is data-kind +PURL-
+type+hashid. A Repository is similar to a shard or tablespace in a traditionale
+database.
+
+4. **Data Directory**: In a Repository, a Data Directory contains the datafiles for
+PURLs. The directory name PURL-type+hashid
+
+5. **Data File**: This is a Data File of the DataCluster's Data Kind that is
+stored in subdirectories structured after the PURL components::
+
+   namespace/name/version/qualifiers/subpath:
+
+- Either at the level of a PURL name: namespace/name,
+- Or at the PURL version level namespace/name/version,
+- Or at the PURL qualifiers+PURL subpath level.
+
+A Data File can be for instance a JSON scan results file, or a list of PURLs in
+YAML.
+
+For example, a list of PURLs as a Data Kind  would stored at the name
+subdirectory level::
+
+    gem-0107/gem/random_password_generator/purls.yml
+
+Or a ScanCode scan as a Data Kind at the version subdirectory level::
+
+    gem-0107/npm/file/3.24.3/scancode.yml
+
+
+
+License
+-------
+
+Copyright (c) AboutCode and others. All rights reserved.
+
+SPDX-License-Identifier: Apache-2.0
+
+See https://github.com/aboutcode-org/vulnerablecode for support or download.
+
+See https://aboutcode.org for more information about AboutCode OSS projects.