cmds/statsd/src/metrics/GaugeMetricProducer.h

/*
 * 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.
 */

#pragma once

#include <unordered_map>

#include <android/util/ProtoOutputStream.h>
#include <gtest/gtest_prod.h>
#include "../condition/ConditionTracker.h"
#include "../external/PullDataReceiver.h"
#include "../external/StatsPullerManager.h"
#include "../matchers/matcher_util.h"
#include "MetricProducer.h"
#include "frameworks/base/cmds/statsd/src/statsd_config.pb.h"
#include "../stats_util.h"

namespace android {
namespace os {
namespace statsd {

struct GaugeBucket {
    int64_t mBucketStartNs;
    int64_t mBucketEndNs;
    std::shared_ptr<EventKV> mEvent;
    uint64_t mBucketNum;
};

// This gauge metric producer first register the puller to automatically pull the gauge at the
// beginning of each bucket. If the condition is met, insert it to the bucket info. Otherwise
// proactively pull the gauge when the condition is changed to be true. Therefore, the gauge metric
// producer always reports the guage at the earliest time of the bucket when the condition is met.
class GaugeMetricProducer : public virtual MetricProducer, public virtual PullDataReceiver {
public:
    // TODO: Pass in the start time from MetricsManager, it should be consistent
    // for all metrics.
    GaugeMetricProducer(const ConfigKey& key, const GaugeMetric& countMetric,
                        const int conditionIndex, const sp<ConditionWizard>& wizard,
                        const int pullTagId, const int atomTagId, const int64_t startTimeNs);

    virtual ~GaugeMetricProducer();

    // Handles when the pulled data arrives.
    void onDataPulled(const std::vector<std::shared_ptr<LogEvent>>& data) override;

    // TODO: Implement this later.
    virtual void notifyAppUpgrade(const string& apk, const int uid, const int64_t version)
            override{};
    // TODO: Implement this later.
    virtual void notifyAppRemoved(const string& apk, const int uid) override{};

protected:
    void onMatchedLogEventInternalLocked(
            const size_t matcherIndex, const HashableDimensionKey& eventKey,
            const std::map<std::string, HashableDimensionKey>& conditionKey, bool condition,
            const LogEvent& event) override;

private:
    void onDumpReportLocked(const uint64_t dumpTimeNs,
                            android::util::ProtoOutputStream* protoOutput) override;

    // for testing
    GaugeMetricProducer(const ConfigKey& key, const GaugeMetric& gaugeMetric,
                        const int conditionIndex, const sp<ConditionWizard>& wizard,
                        const int pullTagId, const int atomTagId, const uint64_t startTimeNs,
                        std::shared_ptr<StatsPullerManager> statsPullerManager);

    // Internal interface to handle condition change.
    void onConditionChangedLocked(const bool conditionMet, const uint64_t eventTime) override;

    // Internal interface to handle sliced condition change.
    void onSlicedConditionMayChangeLocked(const uint64_t eventTime) override;

    // Internal function to calculate the current used bytes.
    size_t byteSizeLocked() const override;

    // Util function to flush the old packet.
    void flushIfNeededLocked(const uint64_t& eventTime);

    // The default bucket size for gauge metric is 1 hr.
    static const uint64_t kDefaultGaugemBucketSizeNs = 60ULL * 60 * 1000 * 1000 * 1000;

    std::shared_ptr<StatsPullerManager> mStatsPullerManager;
    // tagId for pulled data. -1 if this is not pulled
    const int mPullTagId;

    // Save the past buckets and we can clear when the StatsLogReport is dumped.
    // TODO: Add a lock to mPastBuckets.
    std::unordered_map<HashableDimensionKey, std::vector<GaugeBucket>> mPastBuckets;

    // The current bucket.
    std::shared_ptr<DimToEventKVMap> mCurrentSlicedBucket = std::make_shared<DimToEventKVMap>();

    // The current bucket for anomaly detection.
    std::shared_ptr<DimToValMap> mCurrentSlicedBucketForAnomaly = std::make_shared<DimToValMap>();

    // Translate Atom based bucket to single numeric value bucket for anomaly
    void updateCurrentSlicedBucketForAnomaly();

    int mAtomTagId;

    // Whitelist of fields to report. Empty means all are reported.
    std::vector<int> mGaugeFields;

    // apply a whitelist on the original input
    std::shared_ptr<EventKV> getGauge(const LogEvent& event);

    // Util function to check whether the specified dimension hits the guardrail.
    bool hitGuardRailLocked(const HashableDimensionKey& newKey);

    static const size_t kBucketSize = sizeof(GaugeBucket{});

    FRIEND_TEST(GaugeMetricProducerTest, TestWithCondition);
    FRIEND_TEST(GaugeMetricProducerTest, TestNoCondition);
    FRIEND_TEST(GaugeMetricProducerTest, TestAnomalyDetection);
};

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