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Diffstat (limited to 'src/lib/stats/observation.h')
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diff --git a/src/lib/stats/observation.h b/src/lib/stats/observation.h new file mode 100644 index 0000000..f1e0117 --- /dev/null +++ b/src/lib/stats/observation.h @@ -0,0 +1,445 @@ +// Copyright (C) 2015-2020 Internet Systems Consortium, Inc. ("ISC") +// +// This Source Code Form is subject to the terms of the Mozilla Public +// License, v. 2.0. If a copy of the MPL was not distributed with this +// file, You can obtain one at http://mozilla.org/MPL/2.0/. + +#ifndef OBSERVATION_H +#define OBSERVATION_H + +#include <cc/data.h> +#include <exceptions/exceptions.h> +#include <boost/shared_ptr.hpp> +#include <chrono> +#include <list> +#include <stdint.h> + +namespace isc { +namespace stats { + +/// @brief Exception thrown if invalid statistic type is used +/// +/// For example statistic is of type duration, but methods using +/// it as integer are called. +class InvalidStatType : public Exception { +public: + InvalidStatType(const char* file, size_t line, const char* what) : + isc::Exception(file, line, what) {} +}; + +/// @brief Define clock type. +/// +/// @note: we use the system clock i.e. the wall clock because this +/// clock can be converted from and to standard Unix time (time_t). +typedef std::chrono::system_clock SampleClock; + +/// @brief Defines duration type. +/// +/// @note: the precision depends on the system, +typedef std::chrono::system_clock::duration StatsDuration; + +/// @brief Returns the number of seconds in a duration. +/// +/// @param dur The duration. +/// @return The number of seconds in the given duration. +inline long toSeconds(const StatsDuration& dur) { + return ((std::chrono::duration_cast<std::chrono::seconds>(dur)).count()); +} + +/// @defgroup stat_samples Specifies supported observation types. +/// +/// @brief The list covers all supported types of observations. +/// +/// @{ + +/// @brief Integer (implemented as signed 64-bit integer) +typedef std::pair<int64_t, SampleClock::time_point> IntegerSample; + +/// @brief Float (implemented as double precision) +typedef std::pair<double, SampleClock::time_point> FloatSample; + +/// @brief Time Duration +typedef std::pair<StatsDuration, SampleClock::time_point> DurationSample; + +/// @brief String +typedef std::pair<std::string, SampleClock::time_point> StringSample; + +/// @} + +/// @brief Represents a single observable characteristic (a 'statistic') +/// +/// Currently it supports one of four types: integer (implemented as signed 64 +/// bit integer), float (implemented as double), time duration (implemented with +/// millisecond precision) and string. Absolute (setValue) and +/// incremental (addValue) modes are supported. Statistic type is determined +/// during its first use. Once type is set, any additional observations recorded +/// must be of the same type. Attempting to set or extract information about +/// other types will result in InvalidStateType exception. +/// +/// Observation can be retrieved in one of @ref getInteger, @ref getFloat, +/// @ref getDuration, @ref getString (appropriate type must be used) or +/// @ref getJSON, which is generic and can be used for all types. +/// +/// Since Kea 1.6 multiple samples are stored for the same observation. +class Observation { +public: + + /// @brief Type of available statistics + /// + /// Note that those will later be exposed using control socket. Therefore + /// an easy to understand names were chosen (integer instead of uint64). + /// To avoid confusion, we will support only one type of integer and only + /// one type of floating points. Initially, these are represented by + /// int64_t and double. If convincing use cases appear to change them + /// to something else, we may change the underlying type. + enum Type { + STAT_INTEGER, ///< this statistic is unsigned 64-bit integer value + STAT_FLOAT, ///< this statistic is a floating point value + STAT_DURATION,///< this statistic represents time duration + STAT_STRING ///< this statistic represents a string + }; + + /// @brief Constructor for integer observations + /// + /// @param name observation name + /// @param value integer value observed. + Observation(const std::string& name, const int64_t value); + + /// @brief Constructor for floating point observations + /// + /// @param name observation name + /// @param value floating point value observed. + Observation(const std::string& name, const double value); + + /// @brief Constructor for duration observations + /// + /// @param name observation name + /// @param value duration observed. + Observation(const std::string& name, const StatsDuration& value); + + /// @brief Constructor for string observations + /// + /// @param name observation name + /// @param value string observed. + Observation(const std::string& name, const std::string& value); + + /// @brief Determines maximum age of samples. + /// + /// Specifies that statistic name should be stored not as a single value, + /// but rather as a set of values. The duration determines the timespan. + /// Samples older than duration will be discarded. This is time-constrained + /// approach. For sample count constrained approach, see @ref + /// setMaxSampleCount() below. + /// + /// + /// @param duration determines maximum age of samples + /// Example: + /// To set a statistic to keep observations for the last 5 minutes, call: + /// setMaxSampleAge(std::chrono::minutes(5)); + /// To revert statistic to a single value, call: + /// setMaxSampleAge(StatsDuration::zero()); + void setMaxSampleAge(const StatsDuration& duration); + + /// @brief Determines how many samples of a given statistic should be kept. + /// + /// Specifies that statistic name should be stored not as a single value, + /// but rather as a set of values. In this form, at most max_samples will + /// be kept. When adding max_samples + 1 sample, the oldest sample will be + /// discarded. + /// + /// + /// @param max_samples how many samples of a given statistic should be kept + /// Example: + /// To set a statistic to keep the last 100 observations, call: + /// setMaxSampleCount(100); + void setMaxSampleCount(uint32_t max_samples); + + /// @brief Determines default maximum age of samples. + /// + /// @param duration default maximum age of samples to keep. + static void setMaxSampleAgeDefault(const StatsDuration& duration); + + /// @brief Determines default maximum count of samples. + /// + /// @param max_samples default maximum count of samples to keep. + /// (0 means to disable count limit and enable age limit) + static void setMaxSampleCountDefault(uint32_t max_samples); + + /// @brief Get default maximum age of samples. + /// + /// @return default maximum age of samples to keep. + static const StatsDuration& getMaxSampleAgeDefault(); + + /// @brief Get default maximum count of samples. + /// + /// @return max_samples default maximum count of samples to keep. + /// (0 means that count limit was disabled) + static uint32_t getMaxSampleCountDefault(); + + /// @ + + /// @brief Records absolute integer observation + /// + /// @param value integer value observed + /// @throw InvalidStatType if statistic is not integer + void setValue(const int64_t value); + + /// @brief Records absolute floating point observation + /// + /// @param value floating point value observed + /// @throw InvalidStatType if statistic is not fp + void setValue(const double value); + + /// @brief Records absolute duration observation + /// + /// @param value duration value observed + /// @throw InvalidStatType if statistic is not time duration + void setValue(const StatsDuration& value); + + /// @brief Records absolute string observation + /// + /// @param value string value observed + /// @throw InvalidStatType if statistic is not a string + void setValue(const std::string& value); + + /// @brief Records incremental integer observation + /// + /// @param value integer value observed + /// @throw InvalidStatType if statistic is not integer + void addValue(const int64_t value); + + /// @brief Records incremental floating point observation + /// + /// @param value floating point value observed + /// @throw InvalidStatType if statistic is not fp + void addValue(const double value); + + /// @brief Records incremental duration observation + /// + /// @param value duration value observed + /// @throw InvalidStatType if statistic is not time duration + void addValue(const StatsDuration& value); + + /// @brief Records incremental string observation. + /// + /// @param value string value observed + /// @throw InvalidStatType if statistic is not a string + void addValue(const std::string& value); + + /// @brief Returns size of observed storage + /// + /// @return size of storage + size_t getSize() const; + + /// @brief Returns both values of max_sample_age_ of statistic. + /// + /// @return max_sample_age_. + std::pair<bool, StatsDuration> getMaxSampleAge() const; + + /// @brief Returns both values of max_sample_count_ of statistic. + /// + /// @return max_sample_count_. + std::pair<bool, uint32_t> getMaxSampleCount() const; + + /// @brief Resets statistic. + /// + /// Sets statistic to a neutral (0, 0.0 or "") value and + /// clears the underlying storage. + void reset(); + + /// @brief Returns statistic type + /// @return statistic type + Type getType() const { + return (type_); + } + + /// @brief Returns observed integer sample + /// @return observed sample (value + timestamp) + /// @throw InvalidStatType if statistic is not integer + IntegerSample getInteger() const; + + /// @brief Returns observed float sample + /// @return observed sample (value + timestamp) + /// @throw InvalidStatType if statistic is not fp + FloatSample getFloat() const; + + /// @brief Returns observed duration sample + /// @return observed sample (value + timestamp) + /// @throw InvalidStatType if statistic is not time duration + DurationSample getDuration() const; + + /// @brief Returns observed string sample + /// @return observed sample (value + timestamp) + /// @throw InvalidStatType if statistic is not a string + StringSample getString() const; + + /// @brief Returns observed integer samples + /// @return list of observed samples (value + timestamp) + /// @throw InvalidStatType if statistic is not integer + std::list<IntegerSample> getIntegers() const; + + /// @brief Returns observed float samples + /// @return list of observed samples (value + timestamp) + /// @throw InvalidStatType if statistic is not fp + std::list<FloatSample> getFloats() const; + + /// @brief Returns observed duration samples + /// @return list of observed samples (value + timestamp) + /// @throw InvalidStatType if statistic is not time duration + std::list<DurationSample> getDurations() const; + + /// @brief Returns observed string samples + /// @return list of observed samples (value + timestamp) + /// @throw InvalidStatType if statistic is not a string + std::list<StringSample> getStrings() const; + + /// @brief Returns as a JSON structure + /// @return JSON structures representing all observations + isc::data::ConstElementPtr getJSON() const; + + /// @brief Converts statistic type to string + /// @return textual name of statistic type + static std::string typeToText(Type type); + + /// @brief Returns observation name + std::string getName() const { + return (name_); + } + +private: + + /// @brief Returns size of observed storage + /// + /// This method returns size of observed storage. + /// It is used by public methods to return size of + /// available storages. + /// @tparam Storage type of storage (e.g. list<IntegerSample>) + /// @param storage storage which size will be returned + /// @param exp_type expected observation type (used for sanity checking) + /// @return size of storage + template<typename StorageType> + size_t getSizeInternal(StorageType& storage, Type exp_type) const; + + /// @brief Records absolute sample (internal version) + /// + /// This method records an absolute value of an observation. + /// It is used by public methods to add sample to one of + /// available storages. + /// + /// @tparam SampleType type of sample (e.g. IntegerSample) + /// @tparam StorageType type of storage (e.g. list<IntegerSample>) + /// @param value observation to be recorded + /// @param storage observation will be stored here + /// @param exp_type expected observation type (used for sanity checking) + /// @throw InvalidStatType if observation type mismatches + template<typename SampleType, typename StorageType> + void setValueInternal(SampleType value, StorageType& storage, + Type exp_type); + + /// @brief Returns a sample (internal version) + /// + /// @tparam SampleType type of sample (e.g. IntegerSample) + /// @tparam StorageType type of storage (e.g. list<IntegerSample>) + /// @param observation storage + /// @param exp_type expected observation type (used for sanity checking) + /// @throw InvalidStatType if observation type mismatches + /// @return Observed sample + template<typename SampleType, typename Storage> + SampleType getValueInternal(Storage& storage, Type exp_type) const; + + /// @brief Returns samples (internal version) + /// + /// @tparam SampleType type of samples (e.g. IntegerSample) + /// @tparam Storage type of storage (e.g. list<IntegerSample>) + /// @param observation storage + /// @param exp_type expected observation type (used for sanity checking) + /// @throw InvalidStatType if observation type mismatches + /// @return list of observed samples + template<typename SampleType, typename Storage> + std::list<SampleType> getValuesInternal(Storage& storage, + Type exp_type) const; + + /// @brief Determines maximum age of samples. + /// + /// @tparam Storage type of storage (e.g. list<IntegerSample>) + /// @param storage storage on which limit will be set + /// @param duration determines maximum age of samples + /// @param exp_type expected observation type (used for sanity checking) + template<typename StorageType> + void setMaxSampleAgeInternal(StorageType& storage, + const StatsDuration& duration, Type exp_type); + + /// @brief Determines how many samples of a given statistic should be kept. + /// + /// @tparam Storage type of storage (e.g. list<IntegerSample>) + /// @param storage storage on which limit will be set + /// @param max_samples determines maximum number of samples + /// @param exp_type expected observation type (used for sanity checking) + template<typename StorageType> + void setMaxSampleCountInternal(StorageType& storage, + uint32_t max_samples, Type exp_type); + + /// @brief Observation (statistic) name + std::string name_; + + /// @brief Observation (statistic) type) + Type type_; + + /// @brief Maximum number of samples + /// The limit is represented as a pair + /// of bool value and uint32_t + /// Only one kind of limit can be active + /// The bool value informs which limit + /// is available + /// True means active limit, false means inactive limit + std::pair<bool, uint32_t> max_sample_count_; + + /// @brief Default maximum number of samples + /// + /// By default the MaxSampleCount is set to 20 + /// and MaxSampleAge is disabled + static std::pair<bool, uint32_t> default_max_sample_count_; + + /// @brief Maximum timespan of samples + /// The limit is represented as a pair + /// of bool value and StatsDuration + /// Only one kind of limit can be active + /// The bool value informs which limit + /// is available + /// True means active limit, false means inactive limit + std::pair<bool, StatsDuration> max_sample_age_; + + /// @brief Default maximum timespan of samples + /// + /// By default the MaxSampleCount is set to 20 + /// and MaxSampleAge is disabled + static std::pair<bool, StatsDuration> default_max_sample_age_; + + /// @defgroup samples_storage Storage for supported observations + /// + /// @brief The following containers serve as a storage for all supported + /// observation types. + /// + /// @{ + + /// @brief Storage for integer samples + std::list<IntegerSample> integer_samples_; + + /// @brief Storage for floating point samples + std::list<FloatSample> float_samples_; + + /// @brief Storage for time duration samples + std::list<DurationSample> duration_samples_; + + /// @brief Storage for string samples + std::list<StringSample> string_samples_; + /// @} +}; + +/// @brief Observation pointer +typedef boost::shared_ptr<Observation> ObservationPtr; + +} +} + +#endif // OBSERVATION_H |