Tracers

Tracer Interface

The Go Tracer interface creates Spans and understands how to Inject (serialize) and Extract (deserialize) their metadata across process boundaries. It has the following capabilities:

• Start a new Span
• Inject a SpanContext into a carrier
• Extract a SpanContext from a carrier

Each of these will be discussed in more detail below.

Setting up a Tracer

Starting a new Trace

Accessing the Active Span

Propagating a Trace with Inject/Extract

In order to trace across process boundaries in distributed systems, services need to be able to continue the trace injected by the client that sent each request. OpenTracing allows this to happen by providing inject and extract methods that encode a span’s context into a carrier. The inject method allows for the SpanContext to be passed on to a carrier. The extract method does the exact opposite. It extracts the SpanContext from the carrier.