appendable.go

// 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 // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/prometheusreceiver/internal"

import (
	"context"
	"regexp"
	"time"

	"github.com/prometheus/prometheus/model/labels"
	"github.com/prometheus/prometheus/storage"
	"go.opentelemetry.io/collector/component"
	"go.opentelemetry.io/collector/config"
	"go.opentelemetry.io/collector/consumer"
	"go.opentelemetry.io/collector/obsreport"
)

// appendable translates Prometheus scraping diffs into OpenTelemetry format.
type appendable struct {
	sink                 consumer.Metrics
	metricAdjuster       MetricsAdjuster
	useStartTimeMetric   bool
	startTimeMetricRegex *regexp.Regexp
	externalLabels       labels.Labels

	settings component.ReceiverCreateSettings
	obsrecv  *obsreport.Receiver
}

// NewAppendable returns a storage.Appendable instance that emits metrics to the sink.
func NewAppendable(
	sink consumer.Metrics,
	set component.ReceiverCreateSettings,
	gcInterval time.Duration,
	useStartTimeMetric bool,
	startTimeMetricRegex *regexp.Regexp,
	receiverID config.ComponentID,
	externalLabels labels.Labels) storage.Appendable {

	var metricAdjuster MetricsAdjuster
	if !useStartTimeMetric {
		metricAdjuster = NewInitialPointAdjuster(set.Logger, gcInterval)
	} else {
		metricAdjuster = NewStartTimeMetricAdjuster(set.Logger, startTimeMetricRegex)
	}

	return &appendable{
		sink:                 sink,
		settings:             set,
		metricAdjuster:       metricAdjuster,
		useStartTimeMetric:   useStartTimeMetric,
		startTimeMetricRegex: startTimeMetricRegex,
		externalLabels:       externalLabels,
		obsrecv:              obsreport.NewReceiver(obsreport.ReceiverSettings{ReceiverID: receiverID, Transport: transport, ReceiverCreateSettings: set}),
	}
}

func (o *appendable) Appender(ctx context.Context) storage.Appender {
	return newTransaction(ctx, o.metricAdjuster, o.sink, o.externalLabels, o.settings, o.obsrecv)
}