github.com/mre-fog/trillianxx@v1.1.2-0.20180615153820-ae375a99d36a/monitoring/metrics.go (about)

     1  // Copyright 2017 Google Inc. All Rights Reserved.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package monitoring
    16  
    17  // MetricFactory allows the creation of different types of metric.
    18  type MetricFactory interface {
    19  	NewCounter(name, help string, labelNames ...string) Counter
    20  	NewGauge(name, help string, labelNames ...string) Gauge
    21  	NewHistogram(name, help string, labelNames ...string) Histogram
    22  }
    23  
    24  // Counter is a metric class for numeric values that increase.
    25  type Counter interface {
    26  	Inc(labelVals ...string)
    27  	Add(val float64, labelVals ...string)
    28  	Value(labelVals ...string) float64
    29  }
    30  
    31  // Gauge is a metric class for numeric values that can go up and down.
    32  type Gauge interface {
    33  	Inc(labelVals ...string)
    34  	Dec(labelVals ...string)
    35  	Add(val float64, labelVals ...string)
    36  	Set(val float64, labelVals ...string)
    37  	// Value retrieves the value for a particular set of labels.
    38  	// This is only really useful for testing implementations.
    39  	Value(labelVals ...string) float64
    40  }
    41  
    42  // Histogram is a metric class that tracks the distribution of a collection
    43  // of observations.
    44  type Histogram interface {
    45  	Observe(val float64, labelVals ...string)
    46  	// Info retrieves the count and sum of observations for a particular set of labels.
    47  	// This is only really useful for testing implementations.
    48  	Info(labelVals ...string) (uint64, float64)
    49  }