Closes #5929: Emit facts during migration

components/support/migration/src/main/java/mozilla/components/support/migration/AbstractMigrationService.kt

@@ -83,6 +83,8 @@ abstract class AbstractMigrationService : Service() {
     private fun shutdown() {
         store.dispatch(MigrationAction.Completed)
 
+        emitCompletedFact()
+
         stopForeground(true)
 
         showMigrationCompleteNotification()

components/support/migration/src/main/java/mozilla/components/support/migration/FennecMigrator.kt

@@ -551,6 +551,8 @@ class FennecMigrator private constructor(
             store.dispatch(MigrationAction.Started).join()
         }
         ContextCompat.startForegroundService(context, Intent(context, service))
+
+        emitStartedFact()
     }
 
     private fun getMigrationsToRun(): List<VersionedMigration> {

components/support/migration/src/main/java/mozilla/components/support/migration/MigrationFacts.kt

+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package mozilla.components.support.migration
+
+import mozilla.components.support.base.Component
+import mozilla.components.support.base.facts.Action
+import mozilla.components.support.base.facts.Fact
+import mozilla.components.support.base.facts.collect
+
+/**
+ * Facts emitted for telemetry related to migration.
+ */
+class MigrationFacts {
+
+    /**
+     * Items that specify which portion of the migration was invoked.
+     */
+    object Items {
+        const val MIGRATION_COMPLETED = "migration_completed"
+        const val MIGRATION_STARTED = "migration_started"
+    }
+}
+
+private fun emitMigrationFact(
+    action: Action,
+    item: String
+) {
+    Fact(
+        Component.SUPPORT_MIGRATION,
+        action,
+        item
+    ).collect()
+}
+
+internal fun emitCompletedFact() = emitMigrationFact(Action.INTERACTION, MigrationFacts.Items.MIGRATION_COMPLETED)
+internal fun emitStartedFact() = emitMigrationFact(Action.INTERACTION, MigrationFacts.Items.MIGRATION_STARTED)

docs/changelog.md

@@ -72,6 +72,9 @@ permalink: /changelog/
 * **feature-awesomebar**
   * Added `showDescription` parameter (default to `true`) to `SearchSuggestionProvider` constructors to add the possibility of removing search suggestion description.
 
+* **support-migration**
+  * Emit facts during migration.
+
 # 31.0.0
 
 * [Commits](https://github.com/mozilla-mobile/android-components/compare/v30.0.0...v31.0.0)