restic/vendor/go.opencensus.io/stats/view/export.go

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2019-01-27 20:07:57 +00:00
// 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 view
import "sync"
var (
exportersMu sync.RWMutex // guards exporters
exporters = make(map[Exporter]struct{})
)
// Exporter exports the collected records as view data.
//
// The ExportView method should return quickly; if an
// Exporter takes a significant amount of time to
// process a Data, that work should be done on another goroutine.
//
// It is safe to assume that ExportView will not be called concurrently from
// multiple goroutines.
//
// The Data should not be modified.
type Exporter interface {
ExportView(viewData *Data)
}
// RegisterExporter registers an exporter.
// Collected data will be reported via all the
// registered exporters. Once you no longer
// want data to be exported, invoke UnregisterExporter
// with the previously registered exporter.
//
// Binaries can register exporters, libraries shouldn't register exporters.
func RegisterExporter(e Exporter) {
exportersMu.Lock()
defer exportersMu.Unlock()
exporters[e] = struct{}{}
}
// UnregisterExporter unregisters an exporter.
func UnregisterExporter(e Exporter) {
exportersMu.Lock()
defer exportersMu.Unlock()
delete(exporters, e)
}