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Commit b4896df9 authored by TreeHugger Robot's avatar TreeHugger Robot Committed by Android (Google) Code Review
Browse files

Merge "Anomaly detection is per dimension"

parents 6ca624dc 1bf94382

cmds/statsd/src/anomaly/AnomalyTracker.cpp

+18 −39
Original line number Diff line number Diff line
@@ -162,45 +162,23 @@ int64_t AnomalyTracker::getSumOverPastBuckets(const HashableDimensionKey& key) c 
    return 0;

}



bool AnomalyTracker::detectAnomaly(const int64_t& currentBucketNum,

                                   const DimToValMap& currentBucket) {

    if (currentBucketNum > mMostRecentBucketNum + 1) {

        addPastBucket(nullptr, currentBucketNum - 1);

    }

    for (auto itr = currentBucket.begin(); itr != currentBucket.end(); itr++) {

        if (itr->second + getSumOverPastBuckets(itr->first) > mAlert.trigger_if_sum_gt()) {

            return true;

        }

    }

    // In theory, we also need to check the dimsions not in the current bucket. In single-thread

    // mode, usually we could avoid the following loops.

    for (auto itr = mSumOverPastBuckets.begin(); itr != mSumOverPastBuckets.end(); itr++) {

        if (itr->second > mAlert.trigger_if_sum_gt()) {

            return true;

        }

    }

    return false;

}



bool AnomalyTracker::detectAnomaly(const int64_t& currentBucketNum, const HashableDimensionKey& key,

                                   const int64_t& currentBucketValue) {

    if (currentBucketNum > mMostRecentBucketNum + 1) {

        // TODO: This creates a needless 0 entry in mSumOverPastBuckets. Fix this.

        addPastBucket(key, 0, currentBucketNum - 1);

    }

    return mAlert.has_trigger_if_sum_gt()

            && getSumOverPastBuckets(key) + currentBucketValue > mAlert.trigger_if_sum_gt();

}



void AnomalyTracker::declareAnomaly(const uint64_t& timestampNs) {

    // TODO: This should also take in the const HashableDimensionKey& key, to pass

    //       more details to incidentd and to make mRefractoryPeriodEndsSec key-specific.

void AnomalyTracker::declareAnomaly(const uint64_t& timestampNs, const HashableDimensionKey& key) {

    // TODO: Why receive timestamp? RefractoryPeriod should always be based on real time right now.

    if (isInRefractoryPeriod(timestampNs)) {

    if (isInRefractoryPeriod(timestampNs, key)) {

        VLOG("Skipping anomaly declaration since within refractory period");

        return;

    }

    // TODO(guardrail): Consider guarding against too short refractory periods.

    mLastAnomalyTimestampNs = timestampNs;

    mRefractoryPeriodEndsSec[key] = (timestampNs / NS_PER_SEC) + mAlert.refractory_period_secs();



    // TODO: If we had access to the bucket_size_millis, consider calling resetStorage()

    // if (mAlert.refractory_period_secs() > mNumOfPastBuckets * bucketSizeNs) { resetStorage(); }
@@ -208,7 +186,7 @@ void AnomalyTracker::declareAnomaly(const uint64_t& timestampNs) { 
    if (!mSubscriptions.empty()) {

        if (mAlert.has_id()) {

            ALOGI("An anomaly (%llu) has occurred! Informing subscribers.",mAlert.id());

            informSubscribers();

            informSubscribers(key);

        } else {

            ALOGI("An anomaly (with no id) has occurred! Not informing any subscribers.");

        }
@@ -218,6 +196,7 @@ void AnomalyTracker::declareAnomaly(const uint64_t& timestampNs) { 


    StatsdStats::getInstance().noteAnomalyDeclared(mConfigKey, mAlert.id());



    // TODO: This should also take in the const HashableDimensionKey& key?

    android::util::stats_write(android::util::ANOMALY_DETECTED, mConfigKey.GetUid(),

                               mConfigKey.GetId(), mAlert.id());

}
@@ -227,24 +206,24 @@ void AnomalyTracker::detectAndDeclareAnomaly(const uint64_t& timestampNs, 
                                             const HashableDimensionKey& key,

                                             const int64_t& currentBucketValue) {

    if (detectAnomaly(currBucketNum, key, currentBucketValue)) {

        declareAnomaly(timestampNs);

        declareAnomaly(timestampNs, key);

    }

}



void AnomalyTracker::detectAndDeclareAnomaly(const uint64_t& timestampNs,

                                             const int64_t& currBucketNum,

                                             const DimToValMap& currentBucket) {

    if (detectAnomaly(currBucketNum, currentBucket)) {

        declareAnomaly(timestampNs);

bool AnomalyTracker::isInRefractoryPeriod(const uint64_t& timestampNs,

                                          const HashableDimensionKey& key) {

    const auto& it = mRefractoryPeriodEndsSec.find(key);

    if (it != mRefractoryPeriodEndsSec.end()) {

        if ((timestampNs / NS_PER_SEC) <= it->second) {

            return true;

        } else {

            mRefractoryPeriodEndsSec.erase(key);

        }

    }



bool AnomalyTracker::isInRefractoryPeriod(const uint64_t& timestampNs) const {

    return mLastAnomalyTimestampNs >= 0 &&

            timestampNs - mLastAnomalyTimestampNs <= mAlert.refractory_period_secs() * NS_PER_SEC;

    return false;

}



void AnomalyTracker::informSubscribers() {

void AnomalyTracker::informSubscribers(const HashableDimensionKey& key) {

    VLOG("informSubscribers called.");

    if (mSubscriptions.empty()) {

        ALOGE("Attempt to call with no subscribers.");

cmds/statsd/src/anomaly/AnomalyTracker.h

+14 −12
Original line number Diff line number Diff line
@@ -52,16 +52,13 @@ public: 
                       const int64_t& bucketNum);



    // Returns true if detected anomaly for the existing buckets on one or more dimension keys.

    bool detectAnomaly(const int64_t& currBucketNum, const DimToValMap& currentBucket);

    bool detectAnomaly(const int64_t& currBucketNum, const HashableDimensionKey& key,

                       const int64_t& currentBucketValue);



    // Informs incidentd about the detected alert.

    void declareAnomaly(const uint64_t& timestampNs);

    void declareAnomaly(const uint64_t& timestampNs, const HashableDimensionKey& key);



    // Detects the alert and informs the incidentd when applicable.

    void detectAndDeclareAnomaly(const uint64_t& timestampNs, const int64_t& currBucketNum,

                                 const DimToValMap& currentBucket);

    void detectAndDeclareAnomaly(const uint64_t& timestampNs, const int64_t& currBucketNum,

                                 const HashableDimensionKey& key,

                                 const int64_t& currentBucketValue);
@@ -82,9 +79,11 @@ public: 
        return mAlert.trigger_if_sum_gt();

    }



    // Helper function to return the timestamp of the last detected anomaly.

    inline int64_t getLastAnomalyTimestampNs() const {

        return mLastAnomalyTimestampNs;

    // Returns the refractory period timestamp (in seconds) for the given key.

    // If there is no stored refractory period ending timestamp, returns 0.

    uint32_t getRefractoryPeriodEndsSec(const HashableDimensionKey& key) const {

        const auto& it = mRefractoryPeriodEndsSec.find(key);

        return it != mRefractoryPeriodEndsSec.end() ? it->second : 0;

    }



    inline int getNumOfPastBuckets() const {
@@ -121,8 +120,11 @@ protected: 
    // The bucket number of the last added bucket.

    int64_t mMostRecentBucketNum = -1;



    // The timestamp when the last anomaly was declared.

    int64_t mLastAnomalyTimestampNs = -1;

    // Map from each dimension to the timestamp that its refractory period (if this anomaly was

    // declared for that dimension) ends, in seconds. Only anomalies that occur after this period

    // ends will be declared.

    // Entries may be, but are not guaranteed to be, removed after the period is finished.

    unordered_map<HashableDimensionKey, uint32_t> mRefractoryPeriodEndsSec;



    void flushPastBuckets(const int64_t& currBucketNum);
@@ -133,7 +135,7 @@ protected: 
    // and remove any items with value 0.

    void subtractBucketFromSum(const shared_ptr<DimToValMap>& bucket);



    bool isInRefractoryPeriod(const uint64_t& timestampNs) const;

    bool isInRefractoryPeriod(const uint64_t& timestampNs, const HashableDimensionKey& key);



    // Calculates the corresponding bucket index within the circular array.

    size_t index(int64_t bucketNum) const;
@@ -142,12 +144,12 @@ protected: 
    virtual void resetStorage();



    // Informs the subscribers that an anomaly has occurred.

    void informSubscribers();

    void informSubscribers(const HashableDimensionKey& key);



    FRIEND_TEST(AnomalyTrackerTest, TestConsecutiveBuckets);

    FRIEND_TEST(AnomalyTrackerTest, TestSparseBuckets);

    FRIEND_TEST(GaugeMetricProducerTest, TestAnomalyDetection);

    FRIEND_TEST(CountMetricProducerTest, TestAnomalyDetection);

    FRIEND_TEST(CountMetricProducerTest, TestAnomalyDetectionUnSliced);

};



}  // namespace statsd

cmds/statsd/src/anomaly/DurationAnomalyTracker.cpp

+3 −3
Original line number Diff line number Diff line
@@ -46,7 +46,7 @@ void DurationAnomalyTracker::declareAnomalyIfAlarmExpired(const HashableDimensio 


    if (itr->second != nullptr &&

        static_cast<uint32_t>(timestampNs / NS_PER_SEC) >= itr->second->timestampSec) {

        declareAnomaly(timestampNs);

        declareAnomaly(timestampNs, dimensionKey);

        stopAlarm(dimensionKey);

    }

}
@@ -55,7 +55,7 @@ void DurationAnomalyTracker::startAlarm(const HashableDimensionKey& dimensionKey 
                                const uint64_t& timestampNs) {



    uint32_t timestampSec = static_cast<uint32_t>(timestampNs / NS_PER_SEC);

    if (isInRefractoryPeriod(timestampNs)) {

    if (isInRefractoryPeriod(timestampNs, dimensionKey)) {

        VLOG("Skipping setting anomaly alarm since it'd fall in the refractory period");

        return;

    }
@@ -104,7 +104,7 @@ void DurationAnomalyTracker::informAlarmsFired(const uint64_t& timestampNs, 


    // Now declare each of these alarms to have fired.

    for (const auto& kv : matchedAlarms) {

        declareAnomaly(timestampNs /* TODO: , kv.first */);

        declareAnomaly(timestampNs, kv.first);

        mAlarms.erase(kv.first);

        firedAlarms.erase(kv.second);  // No one else can also own it, so we're done with it.

    }

cmds/statsd/src/anomaly/DurationAnomalyTracker.h

+3 −3
Original line number Diff line number Diff line
@@ -50,7 +50,7 @@ public: 
                                      const uint64_t& timestampNs);



    // Declares an anomaly for each alarm in firedAlarms that belongs to this DurationAnomalyTracker

    // and removes it from firedAlarms. Does NOT remove the alarm from the AnomalyMonitor.

    // and removes it from firedAlarms.

    // TODO: This will actually be called from a different thread, so make it thread-safe!

    //          This means that almost every function in DurationAnomalyTracker needs to be locked.

    //          But this should be done at the level of StatsLogProcessor, which needs to lock
@@ -70,10 +70,10 @@ protected: 
    void resetStorage() override;



    FRIEND_TEST(OringDurationTrackerTest, TestPredictAnomalyTimestamp);

    FRIEND_TEST(OringDurationTrackerTest, TestAnomalyDetection);

    FRIEND_TEST(OringDurationTrackerTest, TestAnomalyDetectionExpiredAlarm);

    FRIEND_TEST(OringDurationTrackerTest, TestAnomalyDetectionFiredAlarm);

    FRIEND_TEST(MaxDurationTrackerTest, TestAnomalyDetection);

    FRIEND_TEST(MaxDurationTrackerTest, TestAnomalyDetection);

    FRIEND_TEST(OringDurationTrackerTest, TestAnomalyDetection);

};



}  // namespace statsd

cmds/statsd/src/metrics/CountMetricProducer.h

+1 −1
Original line number Diff line number Diff line
@@ -84,7 +84,7 @@ private: 
    FRIEND_TEST(CountMetricProducerTest, TestNonDimensionalEvents);

    FRIEND_TEST(CountMetricProducerTest, TestEventsWithNonSlicedCondition);

    FRIEND_TEST(CountMetricProducerTest, TestEventsWithSlicedCondition);

    FRIEND_TEST(CountMetricProducerTest, TestAnomalyDetection);

    FRIEND_TEST(CountMetricProducerTest, TestAnomalyDetectionUnSliced);

};



}  // namespace statsd