google.golang.org/grpc@v1.72.2/stats/metrics.go (about)

     1  /*
     2   * Copyright 2024 gRPC authors.
     3   *
     4   * Licensed under the Apache License, Version 2.0 (the "License");
     5   * you may not use this file except in compliance with the License.
     6   * You may obtain a copy of the License at
     7   *
     8   *     http://www.apache.org/licenses/LICENSE-2.0
     9   *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS,
    12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13   * See the License for the specific language governing permissions and
    14   * limitations under the License.
    15   */
    16  
    17  package stats
    18  
    19  import "maps"
    20  
    21  // MetricSet is a set of metrics to record. Once created, MetricSet is immutable,
    22  // however Add and Remove can make copies with specific metrics added or
    23  // removed, respectively.
    24  //
    25  // Do not construct directly; use NewMetricSet instead.
    26  type MetricSet struct {
    27  	// metrics are the set of metrics to initialize.
    28  	metrics map[string]bool
    29  }
    30  
    31  // NewMetricSet returns a MetricSet containing metricNames.
    32  func NewMetricSet(metricNames ...string) *MetricSet {
    33  	newMetrics := make(map[string]bool)
    34  	for _, metric := range metricNames {
    35  		newMetrics[metric] = true
    36  	}
    37  	return &MetricSet{metrics: newMetrics}
    38  }
    39  
    40  // Metrics returns the metrics set. The returned map is read-only and must not
    41  // be modified.
    42  func (m *MetricSet) Metrics() map[string]bool {
    43  	return m.metrics
    44  }
    45  
    46  // Add adds the metricNames to the metrics set and returns a new copy with the
    47  // additional metrics.
    48  func (m *MetricSet) Add(metricNames ...string) *MetricSet {
    49  	newMetrics := make(map[string]bool)
    50  	for metric := range m.metrics {
    51  		newMetrics[metric] = true
    52  	}
    53  
    54  	for _, metric := range metricNames {
    55  		newMetrics[metric] = true
    56  	}
    57  	return &MetricSet{metrics: newMetrics}
    58  }
    59  
    60  // Join joins the metrics passed in with the metrics set, and returns a new copy
    61  // with the merged metrics.
    62  func (m *MetricSet) Join(metrics *MetricSet) *MetricSet {
    63  	newMetrics := make(map[string]bool)
    64  	maps.Copy(newMetrics, m.metrics)
    65  	maps.Copy(newMetrics, metrics.metrics)
    66  	return &MetricSet{metrics: newMetrics}
    67  }
    68  
    69  // Remove removes the metricNames from the metrics set and returns a new copy
    70  // with the metrics removed.
    71  func (m *MetricSet) Remove(metricNames ...string) *MetricSet {
    72  	newMetrics := make(map[string]bool)
    73  	for metric := range m.metrics {
    74  		newMetrics[metric] = true
    75  	}
    76  
    77  	for _, metric := range metricNames {
    78  		delete(newMetrics, metric)
    79  	}
    80  	return &MetricSet{metrics: newMetrics}
    81  }