class LHC::Zipkin
def before_request
def before_request return if !dependencies? || !tracing? ZipkinTracer::TraceContainer.with_trace_id(trace_id) do # add headers even if the current trace_id should not be sampled B3_HEADERS.each { |method, header| request.headers[header] = trace_id.send(method).to_s } # only sample the current call if we're instructed to do so start_trace! if ::Trace.tracer && trace_id.sampled? end end