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opentelemetry-go/exporter/metric/internal/statsd/labels.go
Joshua MacDonald b9706b20f9
Dogstatsd metrics exporter (#326)
* Add MetricAggregator.Merge() implementations

* Update from feedback

* Type

* Ckpt

* Ckpt

* Add push controller

* Ckpt

* Add aggregator interfaces, stdout encoder

* Modify basic main.go

* Main is working

* Batch stdout output

* Sum udpate

* Rename stdout

* Add stateless/stateful Batcher options

* Undo a for-loop in the example, remove a done TODO

* Update imports

* Add note

* Rename defaultkeys

* Support variable label encoder to speed OpenMetrics/Statsd export

* Lint

* Checkpoint

* Checkpoint

* Doc

* Precommit/lint

* Simplify Aggregator API

* Record->Identifier

* Remove export.Record a.k.a. Identifier

* Checkpoint

* Propagate errors to the SDK, remove a bunch of 'TODO warn'

* Checkpoint

* Introduce export.Labels

* Comments in export/metric.go

* Comment

* More merge

* More doc

* Complete example

* Lint fixes

* Add a testable example

* Lint

* Dogstats

* Let Export return an error

* Checkpoint

* add a basic stdout exporter test

* Add measure test; fix aggregator APIs

* Use JSON numbers, not strings

* Test stdout exporter error

* Add a test for the call to RangeTest

* Add error handler API to improve correctness test; return errors from RecordOne

* Undo the previous -- do not expose errors

* Add simple selector variations, test

* Repair examples

* Test push controller error handling

* Add SDK label encoder tests

* Add a defaultkeys batcher test

* Add an ungrouped batcher test

* Lint new tests

* Respond to krnowak's feedback

* Checkpoint

* Funciontal example using unixgram

* Tidy the example

* Add a packet-split test

* More tests

* Undo comment

* Use concrete receivers for export records and labels, since the constructors return structs not pointers

* Bug fix for stateful batchers; clone an aggregator for long term storage

* Remove TODO addressed in #318

* Add errors to all aggregator interfaces

* Handle ErrNoLastValue case in stdout exporter

* Move aggregator API into sdk/export/metric/aggregator

* Update all aggregator exported-method comments

* Document the aggregator APIs

* More aggregator comments

* Add multiple updates to the ungrouped test

* Fixes for feedback from Gustavo and Liz

* Producer->CheckpointSet; add FinishedCollection

* Process takes an export.Record

* ReadCheckpoint->CheckpointSet

* EncodeLabels->Encode

* Format a better inconsistent type error; add more aggregator API tests

* More RangeTest test coverage

* Make benbjohnson/clock a test-only dependency

* Handle ErrNoLastValue in stress_test

* Update comments; use a pipe vs a unix socket in the example test

* Update test

* Spelling

* Typo fix

* Rename DefaultLabelEncoder to NewDefaultLabelEncoder for clarity

* Rename DefaultLabelEncoder to NewDefaultLabelEncoder for clarity

* Test different adapters; add ForceEncode to statsd label encoder
2019-11-21 20:46:05 -08:00

85 lines
2.3 KiB
Go

// Copyright 2019, 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 statsd
import (
"bytes"
"sync"
"go.opentelemetry.io/otel/api/core"
export "go.opentelemetry.io/otel/sdk/export/metric"
)
// LabelEncoder encodes metric labels in the dogstatsd syntax.
//
// TODO: find a link for this syntax. It's been copied out of code,
// not a specification:
//
// https://github.com/stripe/veneur/blob/master/sinks/datadog/datadog.go
type LabelEncoder struct {
pool sync.Pool
}
// sameCheck is used to test whether label encoders are the same.
type sameCheck interface {
isStatsd()
}
var _ export.LabelEncoder = &LabelEncoder{}
// NewLabelEncoder returns a new encoder for dogstatsd-syntax metric
// labels.
func NewLabelEncoder() *LabelEncoder {
return &LabelEncoder{
pool: sync.Pool{
New: func() interface{} {
return &bytes.Buffer{}
},
},
}
}
// Encode emits a string like "|#key1:value1,key2:value2".
func (e *LabelEncoder) Encode(labels []core.KeyValue) string {
buf := e.pool.Get().(*bytes.Buffer)
defer e.pool.Put(buf)
buf.Reset()
delimiter := "|#"
for _, kv := range labels {
_, _ = buf.WriteString(delimiter)
_, _ = buf.WriteString(string(kv.Key))
_, _ = buf.WriteRune(':')
_, _ = buf.WriteString(kv.Value.Emit())
delimiter = ","
}
return buf.String()
}
func (e *LabelEncoder) isStatsd() {}
// ForceEncode returns a statsd label encoding, even if the exported
// labels were encoded by a different type of encoder. Returns a
// boolean to indicate whether the labels were in fact re-encoded, to
// test for (and warn about) efficiency.
func (e *LabelEncoder) ForceEncode(labels export.Labels) (string, bool) {
if _, ok := labels.Encoder().(sameCheck); ok {
return labels.Encoded(), false
}
return e.Encode(labels.Ordered()), true
}