cmds/statsd/src/external/StatsPullerManager.cpp

/*
 * 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 DEBUG false
#include "Log.h"

#include "StatsPullerManager.h"

#include <cutils/log.h>
#include <math.h>
#include <stdint.h>

#include <algorithm>
#include <iostream>

#include "../StatsService.h"
#include "../logd/LogEvent.h"
#include "../stats_log_util.h"
#include "../statscompanion_util.h"
#include "StatsCallbackPuller.h"
#include "TrainInfoPuller.h"
#include "statslog.h"

using std::shared_ptr;
using std::vector;

namespace android {
namespace os {
namespace statsd {

// Values smaller than this may require to update the alarm.
const int64_t NO_ALARM_UPDATE = INT64_MAX;

StatsPullerManager::StatsPullerManager()
    : kAllPullAtomInfo({
              // TrainInfo.
              {{.atomTag = android::util::TRAIN_INFO}, new TrainInfoPuller()},
      }),
      mNextPullTimeNs(NO_ALARM_UPDATE) {
}

bool StatsPullerManager::Pull(int tagId, vector<shared_ptr<LogEvent>>* data) {
    AutoMutex _l(mLock);
    return PullLocked(tagId, data);
}

bool StatsPullerManager::PullLocked(int tagId, vector<shared_ptr<LogEvent>>* data) {
    VLOG("Initiating pulling %d", tagId);

    if (kAllPullAtomInfo.find({.atomTag = tagId}) != kAllPullAtomInfo.end()) {
        bool ret = kAllPullAtomInfo.find({.atomTag = tagId})->second->Pull(data);
        VLOG("pulled %d items", (int)data->size());
        if (!ret) {
            StatsdStats::getInstance().notePullFailed(tagId);
        }
        return ret;
    } else {
        ALOGW("StatsPullerManager: Unknown tagId %d", tagId);
        return false;  // Return early since we don't know what to pull.
    }
}

bool StatsPullerManager::PullerForMatcherExists(int tagId) const {
    // Pulled atoms might be registered after we parse the config, so just make sure the id is in
    // an appropriate range.
    return isVendorPulledAtom(tagId) || isPulledAtom(tagId);
}

void StatsPullerManager::updateAlarmLocked() {
    if (mNextPullTimeNs == NO_ALARM_UPDATE) {
        VLOG("No need to set alarms. Skipping");
        return;
    }

    // TODO(b/149254662): Why are we creating a copy here? This is different
    // from the other places where we create a copy because we don't reassign
    // mStatsCompanionService so a destructor can't implicitly be called...
    shared_ptr<IStatsCompanionService> statsCompanionServiceCopy = mStatsCompanionService;
    if (statsCompanionServiceCopy != nullptr) {
        statsCompanionServiceCopy->setPullingAlarm(mNextPullTimeNs / 1000000);
    } else {
        VLOG("StatsCompanionService not available. Alarm not set.");
    }
    return;
}

void StatsPullerManager::SetStatsCompanionService(
        shared_ptr<IStatsCompanionService> statsCompanionService) {
    // TODO(b/149254662): Why are we using AutoMutex instead of lock_guard?
    // Additionally, do we need the temporary shared_ptr to prevent deadlocks?
    AutoMutex _l(mLock);
    shared_ptr<IStatsCompanionService> tmpForLock = mStatsCompanionService;
    mStatsCompanionService = statsCompanionService;
    for (const auto& pulledAtom : kAllPullAtomInfo) {
        pulledAtom.second->SetStatsCompanionService(statsCompanionService);
    }
    if (mStatsCompanionService != nullptr) {
        updateAlarmLocked();
    }
}

void StatsPullerManager::RegisterReceiver(int tagId, wp<PullDataReceiver> receiver,
                                              int64_t nextPullTimeNs, int64_t intervalNs) {
    AutoMutex _l(mLock);
    auto& receivers = mReceivers[tagId];
    for (auto it = receivers.begin(); it != receivers.end(); it++) {
        if (it->receiver == receiver) {
            VLOG("Receiver already registered of %d", (int)receivers.size());
            return;
        }
    }
    ReceiverInfo receiverInfo;
    receiverInfo.receiver = receiver;

    // Round it to the nearest minutes. This is the limit of alarm manager.
    // In practice, we should always have larger buckets.
    int64_t roundedIntervalNs = intervalNs / NS_PER_SEC / 60 * NS_PER_SEC * 60;
    // Scheduled pulling should be at least 1 min apart.
    // This can be lower in cts tests, in which case we round it to 1 min.
    if (roundedIntervalNs < 60 * (int64_t)NS_PER_SEC) {
        roundedIntervalNs = 60 * (int64_t)NS_PER_SEC;
    }

    receiverInfo.intervalNs = roundedIntervalNs;
    receiverInfo.nextPullTimeNs = nextPullTimeNs;
    receivers.push_back(receiverInfo);

    // There is only one alarm for all pulled events. So only set it to the smallest denom.
    if (nextPullTimeNs < mNextPullTimeNs) {
        VLOG("Updating next pull time %lld", (long long)mNextPullTimeNs);
        mNextPullTimeNs = nextPullTimeNs;
        updateAlarmLocked();
    }
    VLOG("Puller for tagId %d registered of %d", tagId, (int)receivers.size());
}

void StatsPullerManager::UnRegisterReceiver(int tagId, wp<PullDataReceiver> receiver) {
    AutoMutex _l(mLock);
    if (mReceivers.find(tagId) == mReceivers.end()) {
        VLOG("Unknown pull code or no receivers: %d", tagId);
        return;
    }
    auto& receivers = mReceivers.find(tagId)->second;
    for (auto it = receivers.begin(); it != receivers.end(); it++) {
        if (receiver == it->receiver) {
            receivers.erase(it);
            VLOG("Puller for tagId %d unregistered of %d", tagId, (int)receivers.size());
            return;
        }
    }
}

void StatsPullerManager::OnAlarmFired(int64_t elapsedTimeNs) {
    AutoMutex _l(mLock);
    int64_t wallClockNs = getWallClockNs();

    int64_t minNextPullTimeNs = NO_ALARM_UPDATE;

    vector<pair<int, vector<ReceiverInfo*>>> needToPull =
            vector<pair<int, vector<ReceiverInfo*>>>();
    for (auto& pair : mReceivers) {
        vector<ReceiverInfo*> receivers = vector<ReceiverInfo*>();
        if (pair.second.size() != 0) {
            for (ReceiverInfo& receiverInfo : pair.second) {
                if (receiverInfo.nextPullTimeNs <= elapsedTimeNs) {
                    receivers.push_back(&receiverInfo);
                } else {
                    if (receiverInfo.nextPullTimeNs < minNextPullTimeNs) {
                        minNextPullTimeNs = receiverInfo.nextPullTimeNs;
                    }
                }
            }
            if (receivers.size() > 0) {
                needToPull.push_back(make_pair(pair.first, receivers));
            }
        }
    }

    for (const auto& pullInfo : needToPull) {
        vector<shared_ptr<LogEvent>> data;
        bool pullSuccess = PullLocked(pullInfo.first, &data);
        if (pullSuccess) {
            StatsdStats::getInstance().notePullDelay(
                    pullInfo.first, getElapsedRealtimeNs() - elapsedTimeNs);
        } else {
            VLOG("pull failed at %lld, will try again later", (long long)elapsedTimeNs);
        }

        // Convention is to mark pull atom timestamp at request time.
        // If we pull at t0, puller starts at t1, finishes at t2, and send back
        // at t3, we mark t0 as its timestamp, which should correspond to its
        // triggering event, such as condition change at t0.
        // Here the triggering event is alarm fired from AlarmManager.
        // In ValueMetricProducer and GaugeMetricProducer we do same thing
        // when pull on condition change, etc.
        for (auto& event : data) {
            event->setElapsedTimestampNs(elapsedTimeNs);
            event->setLogdWallClockTimestampNs(wallClockNs);
        }

        for (const auto& receiverInfo : pullInfo.second) {
            sp<PullDataReceiver> receiverPtr = receiverInfo->receiver.promote();
            if (receiverPtr != nullptr) {
                receiverPtr->onDataPulled(data, pullSuccess, elapsedTimeNs);
                // We may have just come out of a coma, compute next pull time.
                int numBucketsAhead =
                        (elapsedTimeNs - receiverInfo->nextPullTimeNs) / receiverInfo->intervalNs;
                receiverInfo->nextPullTimeNs += (numBucketsAhead + 1) * receiverInfo->intervalNs;
                if (receiverInfo->nextPullTimeNs < minNextPullTimeNs) {
                    minNextPullTimeNs = receiverInfo->nextPullTimeNs;
                }
            } else {
                VLOG("receiver already gone.");
            }
        }
    }

    VLOG("mNextPullTimeNs: %lld updated to %lld", (long long)mNextPullTimeNs,
         (long long)minNextPullTimeNs);
    mNextPullTimeNs = minNextPullTimeNs;
    updateAlarmLocked();
}

int StatsPullerManager::ForceClearPullerCache() {
    int totalCleared = 0;
    for (const auto& pulledAtom : kAllPullAtomInfo) {
        totalCleared += pulledAtom.second->ForceClearCache();
    }
    return totalCleared;
}

int StatsPullerManager::ClearPullerCacheIfNecessary(int64_t timestampNs) {
    int totalCleared = 0;
    for (const auto& pulledAtom : kAllPullAtomInfo) {
        totalCleared += pulledAtom.second->ClearCacheIfNecessary(timestampNs);
    }
    return totalCleared;
}

void StatsPullerManager::RegisterPullAtomCallback(const int uid, const int32_t atomTag,
                                                  const int64_t coolDownNs, const int64_t timeoutNs,
                                                  const vector<int32_t>& additiveFields,
                                                  const shared_ptr<IPullAtomCallback>& callback) {
    AutoMutex _l(mLock);
    VLOG("RegisterPullerCallback: adding puller for tag %d", atomTag);
    // TODO(b/146439412): linkToDeath with the callback so that we can remove it
    // and delete the puller.
    StatsdStats::getInstance().notePullerCallbackRegistrationChanged(atomTag, /*registered=*/true);
    kAllPullAtomInfo[{.atomTag = atomTag}] =
            new StatsCallbackPuller(atomTag, callback, coolDownNs, timeoutNs, additiveFields);
}

void StatsPullerManager::UnregisterPullAtomCallback(const int uid, const int32_t atomTag) {
    AutoMutex _l(mLock);
    StatsdStats::getInstance().notePullerCallbackRegistrationChanged(atomTag, /*registered=*/false);
    kAllPullAtomInfo.erase({.atomTag = atomTag});
}

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