mirror of
https://github.com/octoleo/restic.git
synced 2024-12-24 20:00:21 +00:00
79 lines
2.8 KiB
Go
79 lines
2.8 KiB
Go
// Copyright 2018, 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 exemplar implements support for exemplars. Exemplars are additional
|
|
// data associated with each measurement.
|
|
//
|
|
// Their purpose it to provide an example of the kind of thing
|
|
// (request, RPC, trace span, etc.) that resulted in that measurement.
|
|
package exemplar
|
|
|
|
import (
|
|
"context"
|
|
"time"
|
|
)
|
|
|
|
const (
|
|
KeyTraceID = "trace_id"
|
|
KeySpanID = "span_id"
|
|
KeyPrefixTag = "tag:"
|
|
)
|
|
|
|
// Exemplar is an example data point associated with each bucket of a
|
|
// distribution type aggregation.
|
|
type Exemplar struct {
|
|
Value float64 // the value that was recorded
|
|
Timestamp time.Time // the time the value was recorded
|
|
Attachments Attachments // attachments (if any)
|
|
}
|
|
|
|
// Attachments is a map of extra values associated with a recorded data point.
|
|
// The map should only be mutated from AttachmentExtractor functions.
|
|
type Attachments map[string]string
|
|
|
|
// AttachmentExtractor is a function capable of extracting exemplar attachments
|
|
// from the context used to record measurements.
|
|
// The map passed to the function should be mutated and returned. It will
|
|
// initially be nil: the first AttachmentExtractor that would like to add keys to the
|
|
// map is responsible for initializing it.
|
|
type AttachmentExtractor func(ctx context.Context, a Attachments) Attachments
|
|
|
|
var extractors []AttachmentExtractor
|
|
|
|
// RegisterAttachmentExtractor registers the given extractor associated with the exemplar
|
|
// type name.
|
|
//
|
|
// Extractors will be used to attempt to extract exemplars from the context
|
|
// associated with each recorded measurement.
|
|
//
|
|
// Packages that support exemplars should register their extractor functions on
|
|
// initialization.
|
|
//
|
|
// RegisterAttachmentExtractor should not be called after any measurements have
|
|
// been recorded.
|
|
func RegisterAttachmentExtractor(e AttachmentExtractor) {
|
|
extractors = append(extractors, e)
|
|
}
|
|
|
|
// NewFromContext extracts exemplars from the given context.
|
|
// Each registered AttachmentExtractor (see RegisterAttachmentExtractor) is called in an
|
|
// unspecified order to add attachments to the exemplar.
|
|
func AttachmentsFromContext(ctx context.Context) Attachments {
|
|
var a Attachments
|
|
for _, extractor := range extractors {
|
|
a = extractor(ctx, a)
|
|
}
|
|
return a
|
|
}
|