MMP.Herald.Sinks.Parquet 0.2.2

Herald.Sinks.Parquet

Writes Herald log events as Apache Parquet files for long-term analytical storage. One Parquet file per batch, seven-column schema (time_utc, level, category, message, template, exception, properties). Optional Iceberg catalog hook (no-op by default) for future table-format integration.

Part of Herald — high-performance structured logging for .NET 8, 9, and 10.

Install

dotnet add package Herald.Sinks.Parquet

The sink auto-registers into LogSinkProviderRegistry.Default via a [ModuleInitializer] on assembly load. No manual RegisterAll(...) or With*SinkProviders() call is required — dotnet add package is the whole workflow.

Sink kind: parquet (the identifier the Dashboard form and JSON config use to reference this sink).

Capabilities

• Apache Parquet 2.x columnar files via Parquet.Net
• Seven-column v1 schema covering the full LogEvent surface
• JSON-encoded properties column (transitional — MAP<STRING,STRING> is the planned target)
• Iceberg catalog seam (IIcebergCatalogClient) with a no-op default, callable after each file closes

Limitations

• One Parquet file per LogBatch — naive sizing, no rolling/aggregation yet (planned for v1.x to match Herald.Sinks.File's evolution path)
• Properties stored as stringified JSON, not native MAP type
• No compression configuration knob — Parquet.Net default applies
• Iceberg integration is a stub interface only; no REST-catalog implementation ships in v1.0

Tier & runtime

• Edition: Community — works on the free Apache 2.0 Herald.Core. No license key required.
• AOT-compatible: yes
• Targets: .NET 8 / 9 / 10
• Thread safety: Thread-safe — each LogBatch call writes its own file. Concurrent callers produce concurrent files; filenames are timestamp-keyed with millisecond resolution so collisions require sub-ms calls on the same writer instance.

Vendor

Apache Parquet — https://parquet.apache.org

Configuration

Per-sink config form lives in configuration*.mmpform at the package root and inside the assembly as an embedded resource. The Herald Dashboard renders it at runtime; JSON config follows the same shape. See CAPABILITY.yaml shipped at the package root for the full manifest (schema reference: CAPABILITY-SCHEMA.md).

License

Apache 2.0. Copyright (c) 2026 MMPWorks LLC. See LICENSE shipped at the package root.

Generated from CAPABILITY.yaml. Re-run Modules/Herald.Sinks/tools/generate-readmes.cjs after manifest edits to refresh.