Add initial implementation of the zpages for Otel Trace (#894)

* Add initial implementation of the zpages for Otel Trace

Signed-off-by: Bogdan Drutu <bogdandrutu@gmail.com>

* Address review comments

Signed-off-by: Bogdan Drutu <bogdandrutu@gmail.com>

* Remove copyright header for new files

Signed-off-by: Bogdan Drutu <bogdandrutu@gmail.com>

* Set go 1.15 in go.mod

Signed-off-by: Bogdan Drutu <bogdandrutu@gmail.com>

.github/dependabot.yml

@@ -494,3 +494,13 @@ updates:
     schedule:
       interval: "weekly"
       day: "sunday"
+  -
+    package-ecosystem: "gomod"
+    directory: "/zpages"
+    labels:
+      - dependencies
+      - go
+      - "Skip Changelog"
+    schedule:
+      interval: "weekly"
+      day: "sunday"

CHANGELOG.md

@@ -8,6 +8,10 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ## [Unreleased]
 
+### Added
+
+- Add the `zpages` span processor. (#894)
+
 ### Fixed
 
 - Fix deadlocks and race conditions in `otelsarama.WrapAsyncProducer`.

zpages/boundaries.go

@@ -0,0 +1,61 @@
+// Copyright The OpenTelemetry Authors
+//
+// 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 zpages
+
+import (
+	"sort"
+	"time"
+)
+
+const zeroDuration = time.Duration(0)
+const maxDuration = time.Duration(1<<63 - 1)
+
+var defaultBoundaries = newBoundaries([]time.Duration{
+	10 * time.Microsecond,
+	100 * time.Microsecond,
+	time.Millisecond,
+	10 * time.Millisecond,
+	100 * time.Millisecond,
+	time.Second,
+	10 * time.Second,
+	100 * time.Second,
+})
+
+// boundaries represents the interval bounds for the latency based samples.
+type boundaries struct {
+	durations []time.Duration
+}
+
+// newBoundaries returns a new boundaries.
+func newBoundaries(durations []time.Duration) *boundaries {
+	sort.Slice(durations, func(i, j int) bool {
+		return durations[i] < durations[j]
+	})
+	return &boundaries{durations: durations}
+}
+
+// numBuckets returns the number of buckets needed for these boundaries.
+func (lb boundaries) numBuckets() int {
+	return len(lb.durations) + 1
+}
+
+// getBucketIndex returns the appropriate bucket index for a given latency.
+func (lb boundaries) getBucketIndex(latency time.Duration) int {
+	i := 0
+	for i < len(lb.durations) && latency >= lb.durations[i] {
+		i++
+	}
+	return i
+}

zpages/boundaries_test.go

@@ -0,0 +1,43 @@
+// Copyright The OpenTelemetry Authors
+//
+// 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 zpages
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+var testDurations = []time.Duration{1 * time.Second}
+
+func TestBoundariesNumBuckets(t *testing.T) {
+	assert.Equal(t, 1, newBoundaries(nil).numBuckets())
+	assert.Equal(t, 1, newBoundaries([]time.Duration{}).numBuckets())
+	assert.Equal(t, 2, newBoundaries(testDurations).numBuckets())
+	assert.Equal(t, 9, defaultBoundaries.numBuckets())
+}
+
+func TestBoundariesGetBucketIndex(t *testing.T) {
+	assert.Equal(t, 0, newBoundaries(testDurations).getBucketIndex(zeroDuration))
+	assert.Equal(t, 0, newBoundaries(testDurations).getBucketIndex(500*time.Millisecond))
+	assert.Equal(t, 1, newBoundaries(testDurations).getBucketIndex(1500*time.Millisecond))
+	assert.Equal(t, 0, newBoundaries(testDurations).getBucketIndex(zeroDuration))
+
+	assert.Equal(t, 0, defaultBoundaries.getBucketIndex(zeroDuration))
+	assert.Equal(t, 3, defaultBoundaries.getBucketIndex(5*time.Millisecond))
+	assert.Equal(t, 6, defaultBoundaries.getBucketIndex(5*time.Second))
+	assert.Equal(t, 8, defaultBoundaries.getBucketIndex(maxDuration))
+}

zpages/bucket.go

@@ -0,0 +1,74 @@
+// Copyright The OpenTelemetry Authors
+// Copyright 2017, OpenCensus Authors
+//
+// 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 zpages
+
+import (
+	"time"
+
+	sdktrace "go.opentelemetry.io/otel/sdk/trace"
+)
+
+const (
+	// defaultBucketCapacity is the default capacity for every bucket (latency or error based).
+	defaultBucketCapacity = 10
+	// samplePeriod is the minimum time between accepting spans in a single bucket.
+	samplePeriod = time.Second
+)
+
+// bucket is a container for a set of spans for latency buckets or errored spans.
+type bucket struct {
+	nextTime  time.Time               // next time we can accept a span
+	buffer    []sdktrace.ReadOnlySpan // circular buffer of spans
+	nextIndex int                     // location next ReadOnlySpan should be placed in buffer
+	overflow  bool                    // whether the circular buffer has wrapped around
+}
+
+// newBucket returns a new bucket with the given capacity.
+func newBucket(capacity uint) *bucket {
+	return &bucket{
+		buffer: make([]sdktrace.ReadOnlySpan, capacity),
+	}
+}
+
+// add adds a span to the bucket, if nextTime has been reached.
+func (b *bucket) add(s sdktrace.ReadOnlySpan) {
+	if s.EndTime().Before(b.nextTime) {
+		return
+	}
+	if len(b.buffer) == 0 {
+		return
+	}
+	b.nextTime = s.EndTime().Add(samplePeriod)
+	b.buffer[b.nextIndex] = s
+	b.nextIndex++
+	if b.nextIndex == len(b.buffer) {
+		b.nextIndex = 0
+		b.overflow = true
+	}
+}
+
+// len returns the number of spans in the bucket.
+func (b *bucket) len() int {
+	if b.overflow {
+		return len(b.buffer)
+	}
+	return b.nextIndex
+}
+
+// spans returns the spans in this bucket.
+func (b *bucket) spans() []sdktrace.ReadOnlySpan {
+	return append([]sdktrace.ReadOnlySpan(nil), b.buffer[0:b.len()]...)
+}

zpages/bucket_test.go

@@ -0,0 +1,104 @@
+// Copyright The OpenTelemetry Authors
+//
+// 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 zpages
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+
+	sdktrace "go.opentelemetry.io/otel/sdk/trace"
+	"go.opentelemetry.io/otel/trace"
+)
+
+type testSpan struct {
+	sdktrace.ReadWriteSpan
+	spanContext trace.SpanContext
+	name        string
+	startTime   time.Time
+	endTime     time.Time
+	status      sdktrace.Status
+}
+
+func (ts *testSpan) SpanContext() trace.SpanContext {
+	return ts.spanContext
+}
+
+func (ts *testSpan) Status() sdktrace.Status {
+	return ts.status
+}
+
+func (ts *testSpan) Name() string {
+	return ts.name
+}
+
+func (ts *testSpan) StartTime() time.Time {
+	return ts.startTime
+}
+
+func (ts *testSpan) EndTime() time.Time {
+	return ts.endTime
+}
+
+func TestBucket(t *testing.T) {
+	bkt := newBucket(defaultBucketCapacity)
+	assert.Equal(t, 0, bkt.len())
+
+	for i := 1; i <= defaultBucketCapacity; i++ {
+		bkt.add(&testSpan{endTime: time.Unix(int64(i), 0)})
+		assert.Equal(t, i, bkt.len())
+		spans := bkt.spans()
+		assert.Len(t, spans, i)
+		for j := 0; j < i; j++ {
+			assert.Equal(t, time.Unix(int64(j+1), 0), spans[j].EndTime())
+		}
+	}
+
+	for i := defaultBucketCapacity + 1; i <= 2*defaultBucketCapacity; i++ {
+		bkt.add(&testSpan{endTime: time.Unix(int64(i), 0)})
+		assert.Equal(t, defaultBucketCapacity, bkt.len())
+		spans := bkt.spans()
+		assert.Len(t, spans, defaultBucketCapacity)
+		// First spans will have newer times, and will replace older timestamps.
+		for j := 0; j < i-defaultBucketCapacity; j++ {
+			assert.Equal(t, time.Unix(int64(j+defaultBucketCapacity+1), 0), spans[j].EndTime())
+		}
+		for j := i - defaultBucketCapacity; j < defaultBucketCapacity; j++ {
+			assert.Equal(t, time.Unix(int64(j+1), 0), spans[j].EndTime())
+		}
+	}
+}
+
+func TestBucketAddSample(t *testing.T) {
+	bkt := newBucket(defaultBucketCapacity)
+	assert.Equal(t, 0, bkt.len())
+
+	for i := 0; i < 1000; i++ {
+		bkt.add(&testSpan{endTime: time.Unix(1, int64(i*1000))})
+		assert.Equal(t, 1, bkt.len())
+		spans := bkt.spans()
+		assert.Len(t, spans, 1)
+		assert.Equal(t, time.Unix(1, 0), spans[0].EndTime())
+	}
+}
+
+func TestBucketZeroCapacity(t *testing.T) {
+	bkt := newBucket(0)
+	assert.Equal(t, 0, bkt.len())
+	bkt.add(&testSpan{endTime: time.Unix(1, 0)})
+	assert.Equal(t, 0, bkt.len())
+	assert.Len(t, bkt.spans(), 0)
+}

zpages/go.mod

@@ -0,0 +1,10 @@
+module go.opentelemetry.io/contrib/zpages
+
+go 1.15
+
+require (
+	github.com/stretchr/testify v1.7.0
+	go.opentelemetry.io/otel v1.0.0-RC1
+	go.opentelemetry.io/otel/sdk v1.0.0-RC1
+	go.opentelemetry.io/otel/trace v1.0.0-RC1
+)

zpages/go.sum

@@ -0,0 +1,23 @@
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/google/go-cmp v0.5.6 h1:BKbKCqvP6I+rmFHt06ZmyQtvB8xAkWdhFyr0ZUNZcxQ=
+github.com/google/go-cmp v0.5.6/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+go.opentelemetry.io/otel v1.0.0-RC1 h1:4CeoX93DNTWt8awGK9JmNXzF9j7TyOu9upscEdtcdXc=
+go.opentelemetry.io/otel v1.0.0-RC1/go.mod h1:x9tRa9HK4hSSq7jf2TKbqFbtt58/TGk0f9XiEYISI1I=
+go.opentelemetry.io/otel/oteltest v1.0.0-RC1 h1:G685iP3XiskCwk/z0eIabL55XUl2gk0cljhGk9sB0Yk=
+go.opentelemetry.io/otel/oteltest v1.0.0-RC1/go.mod h1:+eoIG0gdEOaPNftuy1YScLr1Gb4mL/9lpDkZ0JjMRq4=
+go.opentelemetry.io/otel/sdk v1.0.0-RC1 h1:Sy2VLOOg24bipyC29PhuMXYNJrLsxkie8hyI7kUlG9Q=
+go.opentelemetry.io/otel/sdk v1.0.0-RC1/go.mod h1:kj6yPn7Pgt5ByRuwesbaWcRLA+V7BSDg3Hf8xRvsvf8=
+go.opentelemetry.io/otel/trace v1.0.0-RC1 h1:jrjqKJZEibFrDz+umEASeU3LvdVyWKlnTh7XEfwrT58=
+go.opentelemetry.io/otel/trace v1.0.0-RC1/go.mod h1:86UHmyHWFEtWjfWPSbu0+d0Pf9Q6e1U+3ViBOc+NXAg=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

zpages/internal/gen.go

@@ -0,0 +1,18 @@
+// Copyright The OpenTelemetry Authors
+//
+// 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 internal
+
+// go get https://github.com/mjibson/esc.git
+//go:generate esc -pkg internal -o resources.go templates/