frp/pkg/util/metric/metrics.go

// Copyright 2020 fatedier, fatedier@gmail.com
//
// 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 metric

// GaugeMetric represents a single numerical value that can arbitrarily go up
// and down.
type GaugeMetric interface {
	Inc()
	Dec()
	Set(float64)
}

// CounterMetric represents a single numerical value that only ever
// goes up.
type CounterMetric interface {
	Inc()
}

// HistogramMetric counts individual observations.
type HistogramMetric interface {
	Observe(float64)
}