Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 88525f7d authored by JW Wang's avatar JW Wang
Browse files

Fix the algorithm counting the package failures 

Use the sliding window algorithm to detect if there exists a window
containing failures equal to or above the trigger threshold.

Bug: 140841942
Test: atest PackageWatchdogTest
Change-Id: I34a20e4d3b98a093dffa05fc7c7c026905834b53
parent dfa5268d

services/core/java/com/android/server/PackageWatchdog.java

+12 −17
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ import android.text.TextUtils; 
import android.util.ArrayMap;

import android.util.ArraySet;

import android.util.AtomicFile;

import android.util.LongArrayQueue;

import android.util.Slog;

import android.util.Xml;
@@ -969,6 +970,9 @@ public class PackageWatchdog { 
    class MonitoredPackage {

        //TODO(b/120598832): VersionedPackage?

        private final String mName;

        // Times when package failures happen sorted in ascending order

        @GuardedBy("mLock")

        private final LongArrayQueue mFailureHistory = new LongArrayQueue();

        // One of STATE_[ACTIVE|INACTIVE|PASSED|FAILED]. Updated on construction and after

        // methods that could change the health check state: handleElapsedTimeLocked and

        // tryPassHealthCheckLocked
@@ -988,12 +992,6 @@ public class PackageWatchdog { 
        // of the package, see #getHealthCheckStateLocked

        @GuardedBy("mLock")

        private long mHealthCheckDurationMs = Long.MAX_VALUE;

        // System uptime of first package failure

        @GuardedBy("mLock")

        private long mUptimeStartMs;

        // Number of failures since mUptimeStartMs

        @GuardedBy("mLock")

        private int mFailures;



        MonitoredPackage(String name, long durationMs, boolean hasPassedHealthCheck) {

            this(name, durationMs, Long.MAX_VALUE, hasPassedHealthCheck);
@@ -1028,20 +1026,17 @@ public class PackageWatchdog { 
         */

        @GuardedBy("mLock")

        public boolean onFailureLocked() {

            // Sliding window algorithm: find out if there exists a window containing failures >=

            // mTriggerFailureCount.

            final long now = mSystemClock.uptimeMillis();

            final long duration = now - mUptimeStartMs;

            if (duration > mTriggerFailureDurationMs) {

                // TODO(b/120598832): Reseting to 1 is not correct

                // because there may be more than 1 failure in the last trigger window from now

                // This is the RescueParty impl, will leave for now

                mFailures = 1;

                mUptimeStartMs = now;

            } else {

                mFailures++;

            mFailureHistory.addLast(now);

            while (now - mFailureHistory.peekFirst() > mTriggerFailureDurationMs) {

                // Prune values falling out of the window

                mFailureHistory.removeFirst();

            }

            boolean failed = mFailures >= mTriggerFailureCount;

            boolean failed = mFailureHistory.size() >= mTriggerFailureCount;

            if (failed) {

                mFailures = 0;

                mFailureHistory.clear();

            }

            return failed;

        }

tests/PackageWatchdog/src/com/android/server/PackageWatchdogTest.java

+33 −0
Original line number Diff line number Diff line
@@ -765,6 +765,39 @@ public class PackageWatchdogTest { 
        assertThat(observer.mHealthCheckFailedPackages).containsExactly(APP_B);

    }



    /** Test we are notified when enough failures are triggered within any window. */

    @Test

    public void testFailureTriggerWindow() {

        adoptShellPermissions(

                Manifest.permission.WRITE_DEVICE_CONFIG,

                Manifest.permission.READ_DEVICE_CONFIG);

        DeviceConfig.setProperty(DeviceConfig.NAMESPACE_ROLLBACK,

                PackageWatchdog.PROPERTY_WATCHDOG_TRIGGER_FAILURE_COUNT,

                Integer.toString(3), /*makeDefault*/false);

        DeviceConfig.setProperty(DeviceConfig.NAMESPACE_ROLLBACK,

                PackageWatchdog.PROPERTY_WATCHDOG_TRIGGER_DURATION_MILLIS,

                Integer.toString(1000), /*makeDefault*/false);

        PackageWatchdog watchdog = createWatchdog();

        TestObserver observer = new TestObserver(OBSERVER_NAME_1);



        watchdog.startObservingHealth(observer, Arrays.asList(APP_A), Long.MAX_VALUE);

        // Raise 2 failures at t=0 and t=900 respectively

        watchdog.onPackageFailure(Arrays.asList(new VersionedPackage(APP_A, VERSION_CODE)));

        mTestLooper.dispatchAll();

        moveTimeForwardAndDispatch(900);

        watchdog.onPackageFailure(Arrays.asList(new VersionedPackage(APP_A, VERSION_CODE)));

        mTestLooper.dispatchAll();



        // Raise 2 failures at t=1100

        moveTimeForwardAndDispatch(200);

        watchdog.onPackageFailure(Arrays.asList(new VersionedPackage(APP_A, VERSION_CODE)));

        watchdog.onPackageFailure(Arrays.asList(new VersionedPackage(APP_A, VERSION_CODE)));

        mTestLooper.dispatchAll();



        // We should receive APP_A since there are 3 failures within 1000ms window

        assertThat(observer.mHealthCheckFailedPackages).containsExactly(APP_A);

    }



    private void adoptShellPermissions(String... permissions) {

        InstrumentationRegistry

                .getInstrumentation()