index.md

These four types describe every signal, across all three telemetry pillars — tracing, logging, and metrics. Every span, log record, and metric data point is annotated with Attributes; every provider accepts a Resource; every scope instance is tagged with an InstrumentationScope. Understanding these four types unlocks the rest of the module.

Types

Type	Description
Attributes	Immutable, unboxed parallel-array collection of typed key-value pairs. Carried by every signal: Span, LogRecord, Counter, Resource, and InstrumentationScope.
AttributeKey	Typed key for an Attributes entry. Binds a string name to one of eight value types (String, Long, Double, Boolean, and their Seq variants).
AttributeValue	Boxed existential wrapper for the same eight kinds, used at API boundaries — Logger's vararg attributes, Span#setAttribute, metric label maps — where the type isn't known ahead of time.
Resource	Immutable Attributes wrapper that describes the entity producing telemetry (service name, SDK version, deployment environment). Shared across all three providers.
InstrumentationScope	Named and versioned identity for the library or component that created a signal. Set when calling TracerProvider.get, LoggerProvider.get, or MeterProvider.get.

Design

All four types are designed for hot-path telemetry code:

• Attributes stores Long, Double, and Boolean values unboxed in a parallel primitive array via bit-casting. Reading a value back boxes it — through get, foreach, or a conversion to Map — so hot paths that only write stay allocation-free.
• AttributeKey is a small case class carrying the name and the value type, so a typo in a name or a mismatched type is a compile error rather than a silently separate series.
• Resource is immutable and stamped onto a signal when it is created, not at export: Tracer puts it on every span and Logger on every log record. Metric instruments do not carry it — a MeterProvider holds a Resource, but the Meter and the collected MetricData never see it.
• InstrumentationScope is constructed once per scope by the provider and referenced from all signals that scope creates.

See Also

• Telemetry — module overview and the three-pillar architecture
• Tracing — span lifecycle types that use Attributes and Resource
• Logging — structured log record types that carry Attributes
• Metrics — dimensional measurement types that use Attributes as labels