Track decryption failures

changelog.d/4719.feature

@@ -0,0 +1 @@
+Analytics: Track Errors

matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/algorithms/megolm/MXMegolmDecryption.kt

@@ -133,6 +133,11 @@ internal class MXMegolmDecryption(private val userId: String,
                                     if (requestKeysOnFail) {
                                         requestKeysForEvent(event, false)
                                     }
+
+                                    throw MXCryptoError.Base(
+                                            MXCryptoError.ErrorType.UNKNOWN_MESSAGE_INDEX,
+                                            "UNKNOWN_MESSAGE_INDEX",
+                                            null)
                                 }
 
                                 val reason = String.format(MXCryptoError.OLM_REASON, throwable.olmException.message)

vector/src/main/java/im/vector/app/features/analytics/DecryptionFailureTracker.kt

@@ -0,0 +1,154 @@
+/*
+ * Copyright (c) 2022 New Vector Ltd
+ *
+ * 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.
+ */
+
+package im.vector.app.features.analytics
+
+import im.vector.app.core.flow.tickerFlow
+import im.vector.app.core.time.Clock
+import im.vector.app.features.analytics.plan.Error
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.cancel
+import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.onEach
+import kotlinx.coroutines.launch
+import org.matrix.android.sdk.api.session.crypto.MXCryptoError
+import org.matrix.android.sdk.api.session.room.timeline.TimelineEvent
+import javax.inject.Inject
+import javax.inject.Singleton
+
+private data class DecryptionFailure(
+        val timeStamp: Long,
+        val roomId: String,
+        val failedEventId: String,
+        val error: MXCryptoError.ErrorType
+)
+
+private const val GRACE_PERIOD_MILLIS = 4_000
+private const val CHECK_INTERVAL = 2_000L
+
+/**
+ * Tracks decryption errors that are visible to the user.
+ * When an error is reported it is not directly tracked via analytics, there is a grace period
+ * that gives the app a few seconds to get the key to decrypt.
+ */
+@Singleton
+class DecryptionFailureTracker @Inject constructor(
+        private val vectorAnalytics: VectorAnalytics,
+        private val clock: Clock
+) {
+
+    private val scope: CoroutineScope = CoroutineScope(SupervisorJob())
+    private val failures = mutableListOf<DecryptionFailure>()
+    private val alreadyReported = mutableListOf<String>()
+
+    init {
+        start()
+    }
+
+    fun start() {
+        tickerFlow(scope, CHECK_INTERVAL)
+                .onEach {
+                    checkFailures()
+                }.launchIn(scope)
+    }
+
+    fun stop() {
+        scope.cancel()
+    }
+
+    fun e2eEventDisplayedInTimeline(event: TimelineEvent) {
+        scope.launch(Dispatchers.Default) {
+            val mCryptoError = event.root.mCryptoError
+            if (mCryptoError != null) {
+                addDecryptionFailure(DecryptionFailure(clock.epochMillis(), event.roomId, event.eventId, mCryptoError))
+            } else {
+                removeFailureForEventId(event.eventId)
+            }
+        }
+    }
+
+    /**
+     * Can be called when the timeline is disposed in order
+     * to grace those events as they are not anymore displayed on screen
+     * */
+    fun onTimeLineDisposed(roomId: String) {
+        scope.launch(Dispatchers.Default) {
+            synchronized(failures) {
+                failures.removeIf { it.roomId == roomId }
+            }
+        }
+    }
+
+    private fun addDecryptionFailure(failure: DecryptionFailure) {
+        // de duplicate
+        synchronized(failures) {
+            if (failures.none { it.failedEventId == failure.failedEventId }) {
+                failures.add(failure)
+            }
+        }
+    }
+
+    private fun removeFailureForEventId(eventId: String) {
+        synchronized(failures) {
+            failures.removeIf { it.failedEventId == eventId }
+        }
+    }
+
+    private fun checkFailures() {
+        val now = clock.epochMillis()
+        val aggregatedErrors: Map<Error.Name, List<String>>
+        synchronized(failures) {
+            val toReport = mutableListOf<DecryptionFailure>()
+            failures.removeAll { failure ->
+                (now - failure.timeStamp > GRACE_PERIOD_MILLIS).also {
+                    if (it) {
+                        toReport.add(failure)
+                    }
+                }
+            }
+
+            aggregatedErrors = toReport
+                    .groupBy { it.error.toAnalyticsErrorName() }
+                    .mapValues {
+                        it.value.map { it.failedEventId }
+                    }
+        }
+
+        aggregatedErrors.forEach { aggregation ->
+            // there is now way to send the total/sum in posthog, so iterating
+            aggregation.value
+                    // for now we ignore events already reported even if displayed again?
+                    .filter { alreadyReported.contains(it).not() }
+                    .forEach { failedEventId ->
+                        vectorAnalytics.capture(Error(failedEventId, Error.Domain.E2EE, aggregation.key))
+                        alreadyReported.add(failedEventId)
+                    }
+        }
+    }
+
+    private fun MXCryptoError.ErrorType.toAnalyticsErrorName(): Error.Name {
+        return when (this) {
+            MXCryptoError.ErrorType.UNKNOWN_INBOUND_SESSION_ID -> Error.Name.OlmKeysNotSentError
+            MXCryptoError.ErrorType.OLM                        -> {
+                Error.Name.OlmUnspecifiedError
+            }
+            MXCryptoError.ErrorType.UNKNOWN_MESSAGE_INDEX      -> Error.Name.OlmIndexError
+            else                                               -> Error.Name.UnknownError
+        }
+    }
+}

vector/src/main/java/im/vector/app/features/home/room/detail/RoomDetailViewModel.kt

@@ -38,6 +38,7 @@ import im.vector.app.core.mvrx.runCatchingToAsync
 import im.vector.app.core.platform.VectorViewModel
 import im.vector.app.core.resources.StringProvider
 import im.vector.app.core.utils.BehaviorDataSource
+import im.vector.app.features.analytics.DecryptionFailureTracker
 import im.vector.app.features.call.conference.ConferenceEvent
 import im.vector.app.features.call.conference.JitsiActiveConferenceHolder
 import im.vector.app.features.call.conference.JitsiService
@@ -112,6 +113,7 @@ class RoomDetailViewModel @AssistedInject constructor(
         private val directRoomHelper: DirectRoomHelper,
         private val jitsiService: JitsiService,
         private val activeConferenceHolder: JitsiActiveConferenceHolder,
+        private val decryptionFailureTracker: DecryptionFailureTracker,
         timelineFactory: TimelineFactory
 ) : VectorViewModel<RoomDetailViewState, RoomDetailAction, RoomDetailViewEvents>(initialState),
         Timeline.Listener, ChatEffectManager.Delegate, CallProtocolsChecker.Listener {
@@ -1083,6 +1085,7 @@ class RoomDetailViewModel @AssistedInject constructor(
     override fun onCleared() {
         timeline.dispose()
         timeline.removeAllListeners()
+        decryptionFailureTracker.onTimeLineDisposed(room.roomId)
         if (vectorPreferences.sendTypingNotifs()) {
             room.userStopsTyping()
         }

vector/src/main/java/im/vector/app/features/home/room/detail/timeline/factory/TimelineItemFactory.kt

@@ -19,6 +19,7 @@ package im.vector.app.features.home.room.detail.timeline.factory
 import im.vector.app.core.epoxy.TimelineEmptyItem
 import im.vector.app.core.epoxy.TimelineEmptyItem_
 import im.vector.app.core.epoxy.VectorEpoxyModel
+import im.vector.app.features.analytics.DecryptionFailureTracker
 import im.vector.app.features.home.room.detail.timeline.helper.TimelineEventVisibilityHelper
 import org.matrix.android.sdk.api.session.events.model.EventType
 import org.matrix.android.sdk.api.session.room.timeline.TimelineEvent
@@ -34,6 +35,7 @@ class TimelineItemFactory @Inject constructor(private val messageItemFactory: Me
                                               private val widgetItemFactory: WidgetItemFactory,
                                               private val verificationConclusionItemFactory: VerificationItemFactory,
                                               private val callItemFactory: CallItemFactory,
+                                              private val decryptionFailureTracker: DecryptionFailureTracker,
                                               private val timelineEventVisibilityHelper: TimelineEventVisibilityHelper) {
 
     /**
@@ -122,6 +124,10 @@ class TimelineItemFactory @Inject constructor(private val messageItemFactory: Me
                         Timber.v("Type ${event.root.getClearType()} not handled")
                         defaultItemFactory.create(params)
                     }
+                }.also {
+                    if (it != null && event.isEncrypted()) {
+                        decryptionFailureTracker.e2eEventDisplayedInTimeline(event)
+                    }
                 }
             }
         } catch (throwable: Throwable) {