nordisk/knut

graphar — crate card

Reverse-engineered (from source — verify, don't trust the name)

• One-line pitch: A Rust reader/writer for the Apache GraphAr on-disk graph format (vertex/edge tables + YAML metadata) over multiple file formats and object stores.
• Does: Models GraphAr metadata (GraphInfo, VertexInfo, EdgeInfo, Property, PropertyGroup, AdjListInfo) and reads/writes vertex & edge data as Arrow RecordBatches. Public surface: VertexReader/EdgeReader, VerticesBuilder/EdgesBuilder (Vertex, Edge, PropertyValue), merge_property_groups, and a validation layer (validate_graph_dir, ValidationIssue, Severity). IO backends: Parquet, ORC, Arrow IPC, CSV, JSON.
• Key deps: arrow/arrow-array/arrow-schema/parquet/arrow-csv (columnar IO), orc-rust (ORC), object_store + url + bytes (S3/GCS/Azure/HTTP storage), serde_yaml/serde_json (metadata), thiserror. No intra-workspace deps — this is the base layer.
• Shape: lib only; medium. Modules: metadata/ (graph/vertex/edge/property info), reader/, writer/, io/ (parquet/orc/ipc/json/csv), storage, merge, validate, types, error.
• Observed role in the workspace: Foundational format crate. Consumed by graphar-falkordb (loads its batches into FalkorDB) and transitively by graphar-flight, knut-bifrost, knut-popviz.

Fill in (one line each — only the human knows these)

• Primary consumer(s):
• Why it exists (vs the obvious alternative):
• Hard constraint (airgap / no-C-deps / no-FFI / pure-Rust / etc.):
• Release cadence & independence (rides a parent? own repo someday?):
• Status (production / prototype / experimental / stubbed):
• Must-NOT-change invariant:
• Biggest known gap or TODO:
• Anything a newcomer would get wrong about it: