Statsd Anomaly tracking for CountMetricProducer (a4bc9c4a) · Commits · e / os / android_frameworks_base

cmds/statsd/Android.mk

+1 −1

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		@@ -57,7 +57,7 @@ LOCAL_SRC_FILES := \
		src/metrics/CountMetricProducer.cpp \
		src/metrics/ConditionTracker.cpp \
		src/metrics/MetricsManager.cpp \

		src/metrics/CountAnomalyTracker.cpp \

		LOCAL_CFLAGS += \
		-Wall \

cmds/statsd/src/metrics/CountAnomalyTracker.cpp

0 → 100644

+108 −0

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		/*
		* Copyright (C) 2017 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		#define LOG_TAG "CountAnomaly"
		#define DEBUG true // STOPSHIP if true
		#define VLOG(...) \
		if (DEBUG) ALOGD(__VA_ARGS__);

		#include "CountAnomalyTracker.h"

		#include <cutils/log.h>

		namespace android {
		namespace os {
		namespace statsd {

		CountAnomalyTracker::CountAnomalyTracker(size_t numBuckets, int thresholdGt)
		: mNumPastBuckets(numBuckets > 0 ? numBuckets - 1 : 0),
		mPastBuckets(mNumPastBuckets > 0 ? (new int[mNumPastBuckets]) : nullptr),
		mThresholdGt(thresholdGt) {

		VLOG("CountAnomalyTracker() called");
		if (numBuckets < 1) {
		ALOGE("Cannot create CountAnomalyTracker with %zu buckets", numBuckets);
		}
		reset(); // initialization
		}

		CountAnomalyTracker::~CountAnomalyTracker() {
		VLOG("~CountAnomalyTracker() called");
		}

		void CountAnomalyTracker::addPastBucket(int pastBucketCount,
		time_t numberOfBucketsAgo) {
		VLOG("addPastBucket() called.");
		if (numberOfBucketsAgo < 1) {
		ALOGE("Cannot add a past bucket %ld units in past", numberOfBucketsAgo);
		return;
		}
		// If past bucket was ancient, just empty out all past info.
		// This always applies if mNumPastBuckets == 0 (i.e. store no past buckets).
		if (numberOfBucketsAgo > (time_t) mNumPastBuckets) {
		reset();
		return;
		}

		// Empty out old mPastBuckets[i] values and update mSumPastCounters.
		for (size_t i = mOldestBucketIndex;
		i < mOldestBucketIndex + numberOfBucketsAgo; i++) {
		mSumPastCounters -= mPastBuckets[index(i)];
		mPastBuckets[index(i)] = 0;
		}

		// Replace the oldest bucket with the new bucket we are adding.
		mPastBuckets[mOldestBucketIndex] = pastBucketCount;
		mSumPastCounters += pastBucketCount;

		// Advance the oldest bucket index by numberOfBucketsAgo units.
		mOldestBucketIndex = index(mOldestBucketIndex + numberOfBucketsAgo);

		// TODO: Once dimensions are added to mSumPastCounters:
		// iterate through mSumPastCounters and remove any entries that are 0.
		}

		void CountAnomalyTracker::reset() {
		VLOG("reset() called.");
		for (size_t i = 0; i < mNumPastBuckets; i++) {
		mPastBuckets[i] = 0;
		}
		mSumPastCounters = 0;
		mOldestBucketIndex = 0;
		}

		void CountAnomalyTracker::checkAnomaly(int currentCount) {
		// Note that this works even if mNumPastBuckets < 1 (since then
		// mSumPastCounters = 0 so the comparison is based only on currentCount).

		// TODO: Remove these extremely verbose debugging log.
		VLOG("Checking whether %d + %d > %d",
		mSumPastCounters, currentCount, mThresholdGt);

		if (mSumPastCounters + currentCount > mThresholdGt) {
		declareAnomaly();
		}
		}

		void CountAnomalyTracker::declareAnomaly() {
		// TODO: check that not in refractory period.
		// TODO: Do something.
		ALOGI("An anomaly has occurred!");
		}

		} // namespace statsd
		} // namespace os
		} // namespace android

cmds/statsd/src/metrics/CountAnomalyTracker.h

0 → 100644

+79 −0

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		/*
		* Copyright (C) 2017 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		#ifndef COUNT_ANOMALY_TRACKER_H
		#define COUNT_ANOMALY_TRACKER_H

		#include <stdlib.h>
		#include <memory> // unique_ptr

		namespace android {
		namespace os {
		namespace statsd {

		class CountAnomalyTracker {
		public:
		CountAnomalyTracker(size_t numBuckets, int thresholdGt);

		virtual ~CountAnomalyTracker();


		// Adds a new past bucket, holding pastBucketCount, and then advances the
		// present by numberOfBucketsAgo buckets (filling any intervening buckets
		// with 0s).
		// Thus, the newly added bucket (which holds pastBucketCount) is stored
		// numberOfBucketsAgo buckets ago.
		void addPastBucket(int pastBucketCount, time_t numberOfBucketsAgo);

		// Informs the anomaly tracker of the current bucket's count, so that it can
		// determine whether an anomaly has occurred. This value is not stored.
		void checkAnomaly(int currentCount);

		private:
		// Number of past buckets. One less than the total number of buckets needed
		// for the anomaly detection (since the current bucket is not in the past).
		const size_t mNumPastBuckets;

		// Count values for each of the past mNumPastBuckets buckets.
		// TODO: Add dimensions. This parallels the type of CountMetricProducer.mCounter.
		std::unique_ptr<int[]> mPastBuckets;

		// Sum over all of mPastBuckets (cached).
		// TODO: Add dimensions. This parallels the type of CountMetricProducer.mCounter.
		// At that point, mSumPastCounters must never contain entries of 0.
		int mSumPastCounters;

		// Index of the oldest bucket (i.e. the next bucket to be overwritten).
		size_t mOldestBucketIndex = 0;

		// If mSumPastCounters + currentCount > mThresholdGt --> Anomaly!
		const int mThresholdGt;

		void declareAnomaly();

		// Calculates the corresponding index within the circular array.
		size_t index(size_t unsafeIndex) {
		return unsafeIndex % mNumPastBuckets;
		}

		// Resets all data. For use when all the data gets stale.
		void reset();
		};

		} // namespace statsd
		} // namespace os
		} // namespace android
		#endif // COUNT_ANOMALY_TRACKER_H

cmds/statsd/src/metrics/CountMetricProducer.cpp

+13 −6

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		@@ -20,6 +20,7 @@
		if (DEBUG) ALOGD(__VA_ARGS__);

		#include "CountMetricProducer.h"
		#include "CountAnomalyTracker.h"
		#include "parse_util.h"

		#include <cutils/log.h>
		@@ -38,7 +39,9 @@ CountMetricProducer::CountMetricProducer(const CountMetric& metric,
		mConditionTracker(condition),
		mStartTime(std::time(nullptr)),
		mCounter(0),
		mCurrentBucketStartTime(mStartTime) {
		mCurrentBucketStartTime(mStartTime),
		// TODO: read mAnomalyTracker parameters from config file.
		mAnomalyTracker(6, 10) {
		// TODO: evaluate initial conditions. and set mConditionMet.
		if (metric.has_bucket() && metric.bucket().has_bucket_size_millis()) {
		mBucketSize_sec = metric.bucket().bucket_size_millis() / 1000;
		@@ -78,6 +81,7 @@ void CountMetricProducer::onMatchedLogEvent(const LogEventWrapper& event) {
		if (mConditionTracker->isConditionMet()) {
		flushCounterIfNeeded(eventTime);
		mCounter++;
		mAnomalyTracker.checkAnomaly(mCounter);
		}
		}

		@@ -91,14 +95,17 @@ void CountMetricProducer::flushCounterIfNeeded(const time_t& eventTime) {
		// TODO: add a KeyValuePair to StatsLogReport.
		ALOGD("CountMetric: dump counter %d", mCounter);

		// adjust the bucket start time
		time_t numBucketsForward = (eventTime - mCurrentBucketStartTime)
		/ mBucketSize_sec;

		mCurrentBucketStartTime = mCurrentBucketStartTime +
		(numBucketsForward) * mBucketSize_sec;

		// reset counter
		mAnomalyTracker.addPastBucket(mCounter, numBucketsForward);
		mCounter = 0;

		// adjust the bucket start time
		mCurrentBucketStartTime =
		mCurrentBucketStartTime +
		((eventTime - mCurrentBucketStartTime) / mBucketSize_sec) * mBucketSize_sec;

		VLOG("new bucket start time: %lu", mCurrentBucketStartTime);
		}

cmds/statsd/src/metrics/CountMetricProducer.h

+4 −0

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		@@ -21,6 +21,7 @@
		#include <thread>
		#include <unordered_map>
		#include "../matchers/LogEntryMatcherManager.h"
		#include "CountAnomalyTracker.h"
		#include "ConditionTracker.h"
		#include "DropboxWriter.h"
		#include "MetricProducer.h"
		@@ -52,12 +53,15 @@ private:

		const time_t mStartTime;
		// TODO: Add dimensions.
		// Counter value for the current bucket.
		int mCounter;

		time_t mCurrentBucketStartTime;

		long mBucketSize_sec;

		CountAnomalyTracker mAnomalyTracker;

		void flushCounterIfNeeded(const time_t& newEventTime);
		};