1 files changed, 506 insertions, 0 deletions
diff --git a/src/lib/stats/observation.cc b/src/lib/stats/observation.cc
new file mode 100644
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--- /dev/null
+++ b/src/lib/stats/observation.cc
@@ -0,0 +1,506 @@
+// 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/.
+
+#include <config.h>
+
+#include <stats/observation.h>
+#include <util/chrono_time_utils.h>
+#include <cc/data.h>
+#include <chrono>
+#include <utility>
+
+using namespace std;
+using namespace std::chrono;
+using namespace isc::data;
+
+namespace isc {
+namespace stats {
+
+std::pair<bool, uint32_t>
+Observation::default_max_sample_count_ = std::make_pair(true, 20);
+
+std::pair<bool, StatsDuration>
+Observation::default_max_sample_age_ =
+    std::make_pair(false, StatsDuration::zero());
+
+Observation::Observation(const std::string& name, const int64_t value) :
+    name_(name), type_(STAT_INTEGER),
+    max_sample_count_(default_max_sample_count_),
+    max_sample_age_(default_max_sample_age_) {
+    setValue(value);
+}
+
+Observation::Observation(const std::string& name, const double value) :
+    name_(name), type_(STAT_FLOAT),
+    max_sample_count_(default_max_sample_count_),
+    max_sample_age_(default_max_sample_age_) {
+    setValue(value);
+}
+
+Observation::Observation(const std::string& name, const StatsDuration& value) :
+    name_(name), type_(STAT_DURATION),
+    max_sample_count_(default_max_sample_count_),
+    max_sample_age_(default_max_sample_age_) {
+    setValue(value);
+}
+
+Observation::Observation(const std::string& name, const std::string& value) :
+    name_(name), type_(STAT_STRING),
+    max_sample_count_(default_max_sample_count_),
+    max_sample_age_(default_max_sample_age_) {
+    setValue(value);
+}
+
+void Observation::setMaxSampleAge(const StatsDuration& duration) {
+    switch(type_) {
+    case STAT_INTEGER: {
+        setMaxSampleAgeInternal(integer_samples_, duration, STAT_INTEGER);
+        return;
+    }
+    case STAT_FLOAT: {
+        setMaxSampleAgeInternal(float_samples_, duration, STAT_FLOAT);
+        return;
+    }
+    case STAT_DURATION: {
+        setMaxSampleAgeInternal(duration_samples_, duration, STAT_DURATION);
+        return;
+    }
+    case STAT_STRING: {
+        setMaxSampleAgeInternal(string_samples_, duration, STAT_STRING);
+        return;
+    }
+    default:
+        isc_throw(InvalidStatType, "Unknown statistic type: "
+                  << typeToText(type_));
+    };
+}
+
+void Observation::setMaxSampleCount(uint32_t max_samples) {
+    switch(type_) {
+    case STAT_INTEGER: {
+        setMaxSampleCountInternal(integer_samples_, max_samples, STAT_INTEGER);
+        return;
+    }
+    case STAT_FLOAT: {
+        setMaxSampleCountInternal(float_samples_, max_samples, STAT_FLOAT);
+        return;
+    }
+    case STAT_DURATION: {
+        setMaxSampleCountInternal(duration_samples_, max_samples, STAT_DURATION);
+        return;
+    }
+    case STAT_STRING: {
+        setMaxSampleCountInternal(string_samples_, max_samples, STAT_STRING);
+        return;
+    }
+    default:
+        isc_throw(InvalidStatType, "Unknown statistic type: "
+                  << typeToText(type_));
+    };
+}
+
+void Observation::addValue(const int64_t value) {
+    IntegerSample current = getInteger();
+    setValue(current.first + value);
+}
+
+void Observation::addValue(const double value) {
+    FloatSample current = getFloat();
+    setValue(current.first + value);
+}
+
+void Observation::addValue(const StatsDuration& value) {
+    DurationSample current = getDuration();
+    setValue(current.first + value);
+}
+
+void Observation::addValue(const std::string& value) {
+    StringSample current = getString();
+    setValue(current.first + value);
+}
+
+void Observation::setValue(const int64_t value) {
+    setValueInternal(value, integer_samples_, STAT_INTEGER);
+}
+
+void Observation::setValue(const double value) {
+    setValueInternal(value, float_samples_, STAT_FLOAT);
+}
+
+void Observation::setValue(const StatsDuration& value) {
+    setValueInternal(value, duration_samples_, STAT_DURATION);
+}
+
+void Observation::setValue(const std::string& value) {
+    setValueInternal(value, string_samples_, STAT_STRING);
+}
+
+size_t Observation::getSize() const {
+    size_t size = 0;
+    switch(type_) {
+    case STAT_INTEGER: {
+        size = getSizeInternal(integer_samples_, STAT_INTEGER);
+        return (size);
+    }
+    case STAT_FLOAT: {
+        size = getSizeInternal(float_samples_, STAT_FLOAT);
+        return (size);
+    }
+    case STAT_DURATION: {
+        size = getSizeInternal(duration_samples_, STAT_DURATION);
+        return (size);
+    }
+    case STAT_STRING: {
+        size = getSizeInternal(string_samples_, STAT_STRING);
+        return (size);
+    }
+    default:
+        isc_throw(InvalidStatType, "Unknown statistic type: "
+                  << typeToText(type_));
+    };
+    return (size);
+}
+
+std::pair<bool, StatsDuration> Observation::getMaxSampleAge() const {
+    return (max_sample_age_);
+}
+
+std::pair<bool, uint32_t> Observation::getMaxSampleCount() const {
+    return (max_sample_count_);
+}
+
+template<typename StorageType>
+size_t Observation::getSizeInternal(StorageType& storage, Type exp_type) const {
+    if (type_ != exp_type) {
+        isc_throw(InvalidStatType, "Invalid statistic type requested: "
+                  << typeToText(exp_type) << ", but the actual type is "
+                  << typeToText(type_));
+    } else {
+        return (storage.size());
+    }
+    return (0); // to avoid compilation error
+}
+
+template<typename SampleType, typename StorageType>
+void Observation::setValueInternal(SampleType value, StorageType& storage,
+                                   Type exp_type) {
+    if (type_ != exp_type) {
+        isc_throw(InvalidStatType, "Invalid statistic type requested: "
+                  << typeToText(exp_type) << ", but the actual type is "
+                  << typeToText(type_));
+    }
+
+    if (storage.empty()) {
+        storage.push_back(make_pair(value, SampleClock::now()));
+    } else {
+        // Storing of more than one sample
+        storage.push_front(make_pair(value, SampleClock::now()));
+
+        if (max_sample_count_.first) {
+            // if max_sample_count_ is set to true
+            // and size of storage is equal to max_sample_count_
+            if (storage.size() > max_sample_count_.second) {
+                storage.pop_back(); // removing the last element
+            }
+        } else {
+            StatsDuration range_of_storage =
+                storage.front().second - storage.back().second;
+            // removing samples until the range_of_storage
+            // stops exceeding the duration limit
+            while (range_of_storage > max_sample_age_.second) {
+                storage.pop_back();
+                range_of_storage =
+                    storage.front().second - storage.back().second;
+            }
+        }
+    }
+}
+
+IntegerSample Observation::getInteger() const {
+    return (getValueInternal<IntegerSample>(integer_samples_, STAT_INTEGER));
+}
+
+FloatSample Observation::getFloat() const {
+    return (getValueInternal<FloatSample>(float_samples_, STAT_FLOAT));
+}
+
+DurationSample Observation::getDuration() const {
+    return (getValueInternal<DurationSample>(duration_samples_, STAT_DURATION));
+}
+
+StringSample Observation::getString() const {
+    return (getValueInternal<StringSample>(string_samples_, STAT_STRING));
+}
+
+template<typename SampleType, typename Storage>
+SampleType Observation::getValueInternal(Storage& storage, Type exp_type) const {
+    if (type_ != exp_type) {
+        isc_throw(InvalidStatType, "Invalid statistic type requested: "
+                  << typeToText(exp_type) << ", but the actual type is "
+                  << typeToText(type_));
+    }
+
+    if (storage.empty()) {
+        // That should never happen. The first element is always initialized in
+        // the constructor. reset() sets its value to zero, but the element should
+        // still be there.
+        isc_throw(Unexpected, "Observation storage container empty");
+    }
+    return (*storage.begin());
+}
+
+std::list<IntegerSample> Observation::getIntegers() const {
+    return (getValuesInternal<IntegerSample>(integer_samples_, STAT_INTEGER));
+}
+
+std::list<FloatSample> Observation::getFloats() const {
+    return (getValuesInternal<FloatSample>(float_samples_, STAT_FLOAT));
+}
+
+std::list<DurationSample> Observation::getDurations() const {
+    return (getValuesInternal<DurationSample>(duration_samples_, STAT_DURATION));
+}
+
+std::list<StringSample> Observation::getStrings() const {
+    return (getValuesInternal<StringSample>(string_samples_, STAT_STRING));
+}
+
+template<typename SampleType, typename Storage>
+std::list<SampleType> Observation::getValuesInternal(Storage& storage,
+                                                     Type exp_type) const {
+    if (type_ != exp_type) {
+        isc_throw(InvalidStatType, "Invalid statistic type requested: "
+                  << typeToText(exp_type) << ", but the actual type is "
+                  << typeToText(type_));
+    }
+
+    if (storage.empty()) {
+        // That should never happen. The first element is always initialized in
+        // the constructor. reset() sets its value to zero, but the element should
+        // still be there.
+        isc_throw(Unexpected, "Observation storage container empty");
+    }
+    return (storage);
+}
+
+template<typename StorageType>
+void Observation::setMaxSampleAgeInternal(StorageType& storage,
+                                          const StatsDuration& duration,
+                                          Type exp_type) {
+    if (type_ != exp_type) {
+        isc_throw(InvalidStatType, "Invalid statistic type requested: "
+                  << typeToText(exp_type) << ", but the actual type is "
+                  << typeToText(type_));
+    }
+    // setting new value of max_sample_age_
+    max_sample_age_.first = true;
+    max_sample_age_.second = duration;
+    // deactivating the max_sample_count_ limit
+    max_sample_count_.first = false;
+
+    StatsDuration range_of_storage =
+        storage.front().second - storage.back().second;
+
+    while (range_of_storage > duration) {
+        // deleting elements which are exceeding the duration limit
+        storage.pop_back();
+        range_of_storage = storage.front().second - storage.back().second;
+    }
+}
+
+template<typename StorageType>
+void Observation::setMaxSampleCountInternal(StorageType& storage,
+                                            uint32_t max_samples,
+                                            Type exp_type) {
+    if (type_ != exp_type) {
+        isc_throw(InvalidStatType, "Invalid statistic type requested: "
+                  << typeToText(exp_type) << ", but the actual type is "
+                  << typeToText(type_));
+    }
+    // Should we refuse the max_samples = 0 value here?
+    // setting new value of max_sample_count_
+    max_sample_count_.first = true;
+    max_sample_count_.second = max_samples;
+    // deactivating the max_sample_age_ limit
+    max_sample_age_.first = false;
+
+    while (storage.size() > max_samples) {
+        // deleting elements which are exceeding the max_samples limit
+        storage.pop_back();
+    }
+}
+
+void Observation::setMaxSampleAgeDefault(const StatsDuration& duration) {
+    // setting new value of default_max_sample_age_
+    default_max_sample_age_.second = duration;
+}
+
+void Observation::setMaxSampleCountDefault(uint32_t max_samples) {
+    if (max_samples == 0) {
+        // deactivating the default_max_sample_count_ limit
+        default_max_sample_count_.first = false;
+        default_max_sample_age_.first = true;
+    } else {
+        // setting new value of default_max_sample_count_
+        default_max_sample_count_.second = max_samples;
+        // deactivating the default_max_sample_age_ limit
+        default_max_sample_age_.first = false;
+        default_max_sample_count_.first = true;
+    }
+}
+
+const StatsDuration& Observation::getMaxSampleAgeDefault() {
+    return (default_max_sample_age_.second);
+}
+
+uint32_t Observation::getMaxSampleCountDefault() {
+    if (default_max_sample_count_.first) {
+        return (default_max_sample_count_.second);
+    } else {
+        return (0);
+    }
+}
+
+std::string Observation::typeToText(Type type) {
+    std::stringstream tmp;
+    switch (type) {
+    case STAT_INTEGER:
+        tmp << "integer";
+        break;
+    case STAT_FLOAT:
+        tmp << "float";
+        break;
+    case STAT_DURATION:
+        tmp << "duration";
+        break;
+    case STAT_STRING:
+        tmp << "string";
+        break;
+    default:
+        tmp << "unknown";
+        break;
+    }
+    tmp << "(" << type << ")";
+    return (tmp.str());
+}
+
+isc::data::ConstElementPtr
+Observation::getJSON() const {
+
+    ElementPtr list = isc::data::Element::createList(); // multiple observations
+    ElementPtr entry;
+    ElementPtr value;
+    ElementPtr timestamp;
+
+    // Support for retrieving more than one sample
+    // retrieving all samples of indicated observation
+    switch (type_) {
+    case STAT_INTEGER: {
+        std::list<IntegerSample> s = getIntegers(); // List of all integer samples
+
+        // Iteration over all elements in the list
+        // and adding alternately value and timestamp to the entry
+        for (std::list<IntegerSample>::iterator it = s.begin(); it != s.end(); ++it) {
+            entry = isc::data::Element::createList();
+            value = isc::data::Element::create(static_cast<int64_t>((*it).first));
+            timestamp = isc::data::Element::create(isc::util::clockToText((*it).second));
+
+            entry->add(value);
+            entry->add(timestamp);
+
+            list->add(entry);
+        }
+        break;
+    }
+    case STAT_FLOAT: {
+        std::list<FloatSample> s = getFloats();
+
+        // Iteration over all elements in the list
+        // and adding alternately value and timestamp to the entry
+        for (std::list<FloatSample>::iterator it = s.begin(); it != s.end(); ++it) {
+            entry = isc::data::Element::createList();
+            value = isc::data::Element::create((*it).first);
+            timestamp = isc::data::Element::create(isc::util::clockToText((*it).second));
+
+            entry->add(value);
+            entry->add(timestamp);
+
+            list->add(entry);
+        }
+        break;
+    }
+    case STAT_DURATION: {
+        std::list<DurationSample> s = getDurations();
+
+        // Iteration over all elements in the list
+        // and adding alternately value and timestamp to the entry
+        for (std::list<DurationSample>::iterator it = s.begin(); it != s.end(); ++it) {
+            entry = isc::data::Element::createList();
+            value = isc::data::Element::create(isc::util::durationToText((*it).first));
+            timestamp = isc::data::Element::create(isc::util::clockToText((*it).second));
+
+            entry->add(value);
+            entry->add(timestamp);
+
+            list->add(entry);
+        }
+        break;
+    }
+    case STAT_STRING: {
+        std::list<StringSample> s = getStrings();
+
+        // Iteration over all elements in the list
+        // and adding alternately value and timestamp to the entry
+        for (std::list<StringSample>::iterator it = s.begin(); it != s.end(); ++it) {
+            entry = isc::data::Element::createList();
+            value = isc::data::Element::create((*it).first);
+            timestamp = isc::data::Element::create(isc::util::clockToText((*it).second));
+
+            entry->add(value);
+            entry->add(timestamp);
+
+            list->add(entry);
+        }
+        break;
+    }
+    default:
+        isc_throw(InvalidStatType, "Unknown statistic type: "
+                  << typeToText(type_));
+    };
+
+    return (list);
+}
+
+void Observation::reset() {
+    switch(type_) {
+    case STAT_INTEGER: {
+        integer_samples_.clear();
+        setValue(static_cast<int64_t>(0));
+        return;
+    }
+    case STAT_FLOAT: {
+        float_samples_.clear();
+        setValue(0.0);
+        return;
+    }
+    case STAT_DURATION: {
+        duration_samples_.clear();
+        setValue(StatsDuration::zero());
+        return;
+    }
+    case STAT_STRING: {
+        string_samples_.clear();
+        setValue(string(""));
+        return;
+    }
+    default:
+        isc_throw(InvalidStatType, "Unknown statistic type: "
+                  << typeToText(type_));
+    };
+}
+
+} // end of namespace stats
+} // end of namespace isc