/
exporter.go
133 lines (109 loc) · 3.51 KB
/
exporter.go
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// 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 otlpmetric // import "go.opentelemetry.io/otel/exporters/otlp/otlpmetric"
import (
"context"
"errors"
"sync"
"go.opentelemetry.io/otel/exporters/otlp/otlpmetric/internal/metrictransform"
"go.opentelemetry.io/otel/metric/sdkapi"
"go.opentelemetry.io/otel/sdk/metric/export"
"go.opentelemetry.io/otel/sdk/metric/export/aggregation"
"go.opentelemetry.io/otel/sdk/resource"
metricpb "go.opentelemetry.io/proto/otlp/metrics/v1"
)
var (
errAlreadyStarted = errors.New("already started")
)
// Exporter exports metrics data in the OTLP wire format.
type Exporter struct {
client Client
temporalitySelector aggregation.TemporalitySelector
mu sync.RWMutex
started bool
startOnce sync.Once
stopOnce sync.Once
}
// Export exports a batch of metrics.
func (e *Exporter) Export(ctx context.Context, res *resource.Resource, ilr export.InstrumentationLibraryReader) error {
rm, err := metrictransform.InstrumentationLibraryReader(ctx, e, res, ilr, 1)
if err != nil {
return err
}
if rm == nil {
return nil
}
// TODO: There is never more than one resource emitted by this
// call, as per the specification. We can change the
// signature of UploadMetrics correspondingly. Here create a
// singleton list to reduce the size of the current PR:
return e.client.UploadMetrics(ctx, []*metricpb.ResourceMetrics{rm})
}
// Start establishes a connection to the receiving endpoint.
func (e *Exporter) Start(ctx context.Context) error {
var err = errAlreadyStarted
e.startOnce.Do(func() {
e.mu.Lock()
e.started = true
e.mu.Unlock()
err = e.client.Start(ctx)
})
return err
}
// Shutdown flushes all exports and closes all connections to the receiving endpoint.
func (e *Exporter) Shutdown(ctx context.Context) error {
e.mu.RLock()
started := e.started
e.mu.RUnlock()
if !started {
return nil
}
var err error
e.stopOnce.Do(func() {
err = e.client.Stop(ctx)
e.mu.Lock()
e.started = false
e.mu.Unlock()
})
return err
}
func (e *Exporter) TemporalityFor(descriptor *sdkapi.Descriptor, kind aggregation.Kind) aggregation.Temporality {
return e.temporalitySelector.TemporalityFor(descriptor, kind)
}
var _ export.Exporter = (*Exporter)(nil)
// New constructs a new Exporter and starts it.
func New(ctx context.Context, client Client, opts ...Option) (*Exporter, error) {
exp := NewUnstarted(client, opts...)
if err := exp.Start(ctx); err != nil {
return nil, err
}
return exp, nil
}
// NewUnstarted constructs a new Exporter and does not start it.
func NewUnstarted(client Client, opts ...Option) *Exporter {
cfg := config{
// Note: the default TemporalitySelector is specified
// as Cumulative:
// https://github.com/open-telemetry/opentelemetry-specification/issues/731
temporalitySelector: aggregation.CumulativeTemporalitySelector(),
}
for _, opt := range opts {
opt.apply(&cfg)
}
e := &Exporter{
client: client,
temporalitySelector: cfg.temporalitySelector,
}
return e
}