// 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"

	metricpb "go.opentelemetry.io/proto/otlp/metrics/v1"
)

// Client manages connections to the collector, handles the
// transformation of data into wire format, and the transmission of that
// data to the collector.
type Client interface {
	// Start should establish connection(s) to endpoint(s). It is
	// called just once by the exporter, so the implementation
	// does not need to worry about idempotence and locking.
	Start(ctx context.Context) error
	// Stop should close the connections. The function is called
	// only once by the exporter, so the implementation does not
	// need to worry about idempotence, but it may be called
	// concurrently with UploadMetrics, so proper
	// locking is required. The function serves as a
	// synchronization point - after the function returns, the
	// process of closing connections is assumed to be finished.
	Stop(ctx context.Context) error
	// UploadMetrics should transform the passed metrics to the
	// wire format and send it to the collector. May be called
	// concurrently.
	UploadMetrics(ctx context.Context, protoMetrics []*metricpb.ResourceMetrics) error
}