test-google-cloudtrace.rb

require 'securerandom'
require 'date'

require 'googleauth'
require 'google/apis/cloudtrace_v1'

service = Google::Apis::CloudtraceV1::CloudTraceService.new
service.authorization = Google::Auth.get_application_default(['https://www.googleapis.com/auth/trace.append'])

project_id = 'XXXXX'

t1 = Time.now.utc.round(10).iso8601(6)
sleep 0.05
t2 = Time.now.utc.round(10).iso8601(6)

span = Google::Apis::CloudtraceV1::TraceSpan.new(
  name: '/test',
  span_id: 1.to_s,
  start_time:  t1,
  end_time: t2,
  labels: {},
  kind: 'RPC_SERVER',
)

trace = Google::Apis::CloudtraceV1::Trace.new(
  trace_id: SecureRandom.uuid.split('-').join,
  project_id: project_id,
  spans: [span]
)
traces = Google::Apis::CloudtraceV1::Traces.new(traces: [trace])

response = service.patch_project_traces(project_id, traces)
puts response.inspect

API
https://cloud.google.com/trace/api/reference/rpc/google.devtools.cloudtrace.v1#google.devtools.cloudtrace.v1.TraceSpan.SpanKind

Rb
http://www.rubydoc.info/github/google/google-api-ruby-client/Google/Apis/CloudtraceV1/TraceSpan