ceph/src/seastar/include/seastar/core/metrics_registration.hh

   1 /*
   2  * This file is open source software, licensed to you under the terms
   3  * of the Apache License, Version 2.0 (the "License").  See the NOTICE file
   4  * distributed with this work for additional information regarding copyright
   5  * ownership.  You may not use this file except in compliance with the License.
   6  *
   7  * You may obtain a copy of the License at
   8  *
   9  *   http://www.apache.org/licenses/LICENSE-2.0
  10  *
  11  * Unless required by applicable law or agreed to in writing,
  12  * software distributed under the License is distributed on an
  13  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  14  * KIND, either express or implied.  See the License for the
  15  * specific language governing permissions and limitations
  16  * under the License.
  17  */
  18 /*
  19  * Copyright (C) 2016 ScyllaDB.
  20  */
  21
  22 #pragma once
  23
  24 /*!
  25  * \file metrics_registration.hh
  26  * \brief holds the metric_groups definition needed by class that reports metrics
  27  *
  28  * If class A needs to report metrics,
  29  * typically you include metrics_registration.hh, in A header file and add to A:
  30  * * metric_groups _metrics as a member
  31  * * set_metrics() method that would be called in the constructor.
  32  * \code
  33  * class A {
  34  *   metric_groups _metrics
  35  *
  36  *   void setup_metrics();
  37  *
  38  * };
  39  * \endcode
  40  * To define the metrics, include in your source file metircs.hh
  41  * @see metrics.hh for the definition for adding a metric.
  42  */
  43
  44 namespace seastar {
  45
  46 namespace metrics {
  47
  48 namespace impl {
  49 class metric_groups_def;
  50 struct metric_definition_impl;
  51 class metric_groups_impl;
  52 }
  53
  54 using group_name_type = sstring; /*!< A group of logically related metrics */
  55 class metric_groups;
  56
  57 class metric_definition {
  58     std::unique_ptr<impl::metric_definition_impl> _impl;
  59 public:
  60     metric_definition(const impl::metric_definition_impl& impl) noexcept;
  61     metric_definition(metric_definition&& m) noexcept;
  62     ~metric_definition();
  63     friend metric_groups;
  64     friend impl::metric_groups_impl;
  65 };
  66
  67 class metric_group_definition {
  68 public:
  69     group_name_type name;
  70     std::initializer_list<metric_definition> metrics;
  71     metric_group_definition(const group_name_type& name, std::initializer_list<metric_definition> l);
  72     metric_group_definition(const metric_group_definition&) = delete;
  73     ~metric_group_definition();
  74 };
  75
  76 /*!
  77  * metric_groups
  78  * \brief holds the metric definition.
  79  *
  80  * Add multiple metric groups definitions.
  81  * Initialization can be done in the constructor or with a call to add_group
  82  * @see metrics.hh for example and supported metrics
  83  */
  84 class metric_groups {
  85     std::unique_ptr<impl::metric_groups_def> _impl;
  86 public:
  87     metric_groups() noexcept;
  88     metric_groups(metric_groups&&) = default;
  89     virtual ~metric_groups();
  90     metric_groups& operator=(metric_groups&&) = default;
  91     /*!
  92      * \brief add metrics belong to the same group in the constructor.
  93      *
  94      * combine the constructor with the add_group functionality.
  95      */
  96     metric_groups(std::initializer_list<metric_group_definition> mg);
  97
  98     /*!
  99      * \brief add metrics belong to the same group.
 100      *
 101      * use the metrics creation functions to add metrics.
 102      *
 103      * for example:
 104      *  _metrics.add_group("my_group", {
 105      *      make_counter("my_counter_name1", counter, description("my counter description")),
 106      *      make_counter("my_counter_name2", counter, description("my second counter description")),
 107      *      make_gauge("my_gauge_name1", gauge, description("my gauge description")),
 108      *  });
 109      *
 110      *  metric name should be unique inside the group.
 111      *  you can change add_group calls like:
 112      *  _metrics.add_group("my group1", {...}).add_group("my group2", {...});
 113      */
 114     metric_groups& add_group(const group_name_type& name, const std::initializer_list<metric_definition>& l);
 115
 116     /*!
 117      * \brief clear all metrics groups registrations.
 118      */
 119     void clear();
 120 };
 121
 122
 123 /*!
 124  * \brief hold a single metric group
 125  * Initialization is done in the constructor or
 126  * with a call to add_group
 127  */
 128 class metric_group : public metric_groups {
 129 public:
 130     metric_group() noexcept;
 131     metric_group(const metric_group&) = delete;
 132     metric_group(metric_group&&) = default;
 133     virtual ~metric_group();
 134     metric_group& operator=(metric_group&&) = default;
 135
 136     /*!
 137      * \brief add metrics belong to the same group in the constructor.
 138      *
 139      *
 140      */
 141     metric_group(const group_name_type& name, std::initializer_list<metric_definition> l);
 142 };
 143
 144
 145 }
 146 }