swarm: integrate OpenTracing; propagate ctx to internal APIs (#17169)

* swarm: propagate ctx, enable opentracing

* swarm/tracing: log error when tracing is misconfigured

vendor/github.com/uber/jaeger-client-go/metrics.go

@@ -0,0 +1,107 @@
+// Copyright (c) 2017-2018 Uber Technologies, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package jaeger
+
+import (
+	"github.com/uber/jaeger-lib/metrics"
+)
+
+// Metrics is a container of all stats emitted by Jaeger tracer.
+type Metrics struct {
+	// Number of traces started by this tracer as sampled
+	TracesStartedSampled metrics.Counter `metric:"traces" tags:"state=started,sampled=y"`
+
+	// Number of traces started by this tracer as not sampled
+	TracesStartedNotSampled metrics.Counter `metric:"traces" tags:"state=started,sampled=n"`
+
+	// Number of externally started sampled traces this tracer joined
+	TracesJoinedSampled metrics.Counter `metric:"traces" tags:"state=joined,sampled=y"`
+
+	// Number of externally started not-sampled traces this tracer joined
+	TracesJoinedNotSampled metrics.Counter `metric:"traces" tags:"state=joined,sampled=n"`
+
+	// Number of sampled spans started by this tracer
+	SpansStartedSampled metrics.Counter `metric:"started_spans" tags:"sampled=y"`
+
+	// Number of unsampled spans started by this tracer
+	SpansStartedNotSampled metrics.Counter `metric:"started_spans" tags:"sampled=n"`
+
+	// Number of spans finished by this tracer
+	SpansFinished metrics.Counter `metric:"finished_spans"`
+
+	// Number of errors decoding tracing context
+	DecodingErrors metrics.Counter `metric:"span_context_decoding_errors"`
+
+	// Number of spans successfully reported
+	ReporterSuccess metrics.Counter `metric:"reporter_spans" tags:"result=ok"`
+
+	// Number of spans not reported due to a Sender failure
+	ReporterFailure metrics.Counter `metric:"reporter_spans" tags:"result=err"`
+
+	// Number of spans dropped due to internal queue overflow
+	ReporterDropped metrics.Counter `metric:"reporter_spans" tags:"result=dropped"`
+
+	// Current number of spans in the reporter queue
+	ReporterQueueLength metrics.Gauge `metric:"reporter_queue_length"`
+
+	// Number of times the Sampler succeeded to retrieve sampling strategy
+	SamplerRetrieved metrics.Counter `metric:"sampler_queries" tags:"result=ok"`
+
+	// Number of times the Sampler failed to retrieve sampling strategy
+	SamplerQueryFailure metrics.Counter `metric:"sampler_queries" tags:"result=err"`
+
+	// Number of times the Sampler succeeded to retrieve and update sampling strategy
+	SamplerUpdated metrics.Counter `metric:"sampler_updates" tags:"result=ok"`
+
+	// Number of times the Sampler failed to update sampling strategy
+	SamplerUpdateFailure metrics.Counter `metric:"sampler_updates" tags:"result=err"`
+
+	// Number of times baggage was successfully written or updated on spans.
+	BaggageUpdateSuccess metrics.Counter `metric:"baggage_updates" tags:"result=ok"`
+
+	// Number of times baggage failed to write or update on spans.
+	BaggageUpdateFailure metrics.Counter `metric:"baggage_updates" tags:"result=err"`
+
+	// Number of times baggage was truncated as per baggage restrictions.
+	BaggageTruncate metrics.Counter `metric:"baggage_truncations"`
+
+	// Number of times baggage restrictions were successfully updated.
+	BaggageRestrictionsUpdateSuccess metrics.Counter `metric:"baggage_restrictions_updates" tags:"result=ok"`
+
+	// Number of times baggage restrictions failed to update.
+	BaggageRestrictionsUpdateFailure metrics.Counter `metric:"baggage_restrictions_updates" tags:"result=err"`
+
+	// Number of times debug spans were throttled.
+	ThrottledDebugSpans metrics.Counter `metric:"throttled_debug_spans"`
+
+	// Number of times throttler successfully updated.
+	ThrottlerUpdateSuccess metrics.Counter `metric:"throttler_updates" tags:"result=ok"`
+
+	// Number of times throttler failed to update.
+	ThrottlerUpdateFailure metrics.Counter `metric:"throttler_updates" tags:"result=err"`
+}
+
+// NewMetrics creates a new Metrics struct and initializes it.
+func NewMetrics(factory metrics.Factory, globalTags map[string]string) *Metrics {
+	m := &Metrics{}
+	// TODO the namespace "jaeger" should be configurable (e.g. in all-in-one "jaeger-client" would make more sense)
+	metrics.Init(m, factory.Namespace("jaeger", nil), globalTags)
+	return m
+}
+
+// NewNullMetrics creates a new Metrics struct that won't report any metrics.
+func NewNullMetrics() *Metrics {
+	return NewMetrics(metrics.NullFactory, nil)
+}