log101T

Log101T is a hypothetical open standard for structured log records intended for distributed systems and cloud telemetry. It defines a compact, extensible schema and a minimal emitting API to enable interoperability among services written in different languages. The "T" in log101T stands for Telemetry, highlighting the format’s emphasis on time-ordered, traceable event data.

Record format and fields: A log101T entry includes a timestamp (ISO 8601 or epoch milliseconds), a severity level (debug, info, warn, error, critical), a source or component name, an event_id, and a message. Optional context is captured as a structured map. Additional fields such as tags, correlation_id, trace_id, and span_id support distributed tracing. The specification allows both JSON encoding and a compact binary variant, and it defines versioned schemas designed for forward and backward compatibility.

Usage and tooling: Emitters and consumers implement a log101T interface in the host language; validators check conformance against a declared schema; and a registry or catalog can provide schemas and extensions. The standard emphasizes streaming compatibility, low parsing overhead, and suitability for high-volume logs. It supports integration with data pipelines, archival workflows, and observability stacks.

History and status: The concept originated from a collaborative community in the mid-2010s as an attempt to unify structured logging for telemetry. Since then, log101T has undergone multiple revisions (1.x) to address evolving requirements and interoperability challenges. Adoption has been modest and largely limited to experimental projects and educational resources within this article’s context. Real-world usage varies by organization and tooling.

See also: logfmt, JSON Lines, OpenTelemetry, structured logging.