MMP.Herald.Sinks.Otlp 0.2.1

Herald.Sinks.Otlp

Three sinks for the OpenTelemetry Logs Protocol that share serialization infrastructure: OtlpJsonLogSink posts JSON to an OTLP collector, OtlpProtobufLogSink posts binary protobuf to the same endpoint, and ProtobufFileLogSink writes length-delimited protobuf records to a local .pb file for offline ingestion. The hand-rolled protobuf writer keeps the package AOT-clean — no generated message classes, no reflection paths the trim analyzer has to defeat.

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

Install

dotnet add package Herald.Sinks.Otlp

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: otlp_json | otlp_protobuf | protobuf_file (the identifier the Dashboard form and JSON config use to reference this sink).

Capabilities

• Three sinks in one package — pick network (JSON or protobuf) or file
• Hand-rolled protobuf writer — AOT-clean, no generated IMessage types
• OTLP semantic conventions (severityNumber, severityText, body, attributes, resource, traceId, spanId)
• Batched delivery via IBatchedLogSink for the network sinks
• Length-delimited protobuf framing for the file sink (readable by streaming readers)
• Rolling-by-size for the file sink (max file size, automatic sequential rollover)
• Hex-nibble trace/span id parsing with no exception path (perf-aware)

Limitations

• No gRPC transport — HTTP/1.1 only. gRPC-OTLP is a future enhancement.
• Resource attributes configurable at construction only
• No compression on the request body

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: Network sinks thread-safe via shared HttpClient. File sink serializes writes under a private lock so single-writer and concurrent-writer workloads both behave.

Vendor

OpenTelemetry — https://opentelemetry.io/docs/specs/otlp/

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.