Embracing WorkManager - DevFest19 edition

After all of 2018 spent as alpha and beta, WorkManager graduated in 2019 to its first stable release and it is now the recommended solution for scheduling and executing deferrable background tasks in Android.
In this talk we’ll quickly look into which use cases are a good fit for WorkManager, and which are better handled by different tools/APIs. Then we will jump into the API itself covering the different options available, from the simple Worker class to the newer CoroutineWorker.
All this with an eye on how you can (and should) test your Workers and how you can implement some of the few missing features that are not yet covered by WorkManager out of the box.
With this talk you’ll learn:
When to use (and when not) WorkManager
Which Worker class to use for your particular use case
How to test your Worker classes

Transcript

2. Embracing WorkManager Pietro Maggi | Android DevRel Engineer @ Google bit.ly/pfm-wm-devfest19
3. The basics ..or what is WorkManager
4. Part of Android Jetpack Accelerate development Eliminate boilerplate code Build high quality, robust apps
5. WorkManager is an Android library that runs deferrable background work when the constraints are satisfied. WorkManager
6. WorkManager is an Android library that runs deferrable background work when the constraints are satisfied. WorkManager
7. WorkManager is an Android library that runs deferrable background work when the constraints are satisfied. WorkManager is intended for tasks that require a guarantee that the system will run them even if the app exits. WorkManager
8. WorkManager is an Android library that runs deferrable background work when the constraints are satisfied. WorkManager is intended for tasks that require a guarantee that the system will run them even if the app exits. WorkManager
9. • Asynchronous one-off and periodic tasks WorkManager Benefits Compress
10. • Asynchronous one-off and periodic tasks • Chaining with Input/Output WorkManager Benefits Upload Compress Filter Image 2 Filter Image 3 Filter Image 1
11. • Asynchronous one-off and periodic tasks • Chaining with Input/Output • Constraints WorkManager Benefits Upload Compress Filter Image 2 Filter Image 3 Filter Image 1 Battery not low Storage not low Has Network
12. • Asynchronous one-off and periodic tasks • Chaining with Input/Output • Constraints • Handles compatibility • System health best practices • Guaranteed execution WorkManager Benefits Upload Compress Filter Image 2 Filter Image 3 Filter Image 1 Battery not low Storage not low Has Network
13. I need to run a task
14. Has to finish? I need to run a task
15. Executor* or Coroutines Has to finish? I need to run a task NO *If you have system triggers, use a broadcast receiver to get notified
16. Executor* or Coroutines Is Deferrable? Has to finish? I need to run a task YES NO *If you have system triggers, use a broadcast receiver to get notified
17. NO Executor* or Coroutines Is Deferrable? Has to finish? I need to run a task YES NO Foreground Service* *If you have system triggers, use a broadcast receiver to get notified
18. NO Executor* or Coroutines WorkManager Is Deferrable? Has to finish? I need to run a task YES NO Foreground Service* *If you have system triggers, use a broadcast receiver to get notified YES
19. NO Executor* or Coroutines WorkManager Is Deferrable? Has to finish? I need to run a task YES NO Foreground Service* *If you have system triggers, use a broadcast receiver to get notified YES v 2.3-alpha02
20. Release History 1.0 / 2.0 Initial release in support lib (1.0) / AndroidX (2.0) 1.0 / 2.0
21. Release History 1.0 / 2.0 On-demand initialization, new testing support 2.1 2.1
22. Release History Present GcmNetworkManager support (API 22 and below) 2.1 2.2 1.0 / 2.0
23. Release History Future Progress and setForeground APIs 2.1 2.3 1.0 / 2.0 2.2
24. WorkManager’s Worker classes
25. ListenableWorker Worker Meet the Worker Family! RxWorker CoroutineWorker* *Only available using Kotlin
26. class LocationWorker(context : Context, params : WorkerParameters) : ListenableWorker(context, params) { val future = ResolvableFuture.create<Result>() override fun startWork(): ListenableFuture<Result> { if (hasPermissions()) { getLocation() } else { future.set(Result.failure()) } return future } } ListenableWorker
27. class LocationWorker(context : Context, params : WorkerParameters) : ListenableWorker(context, params) { val future = ResolvableFuture.create<Result>() override fun startWork(): ListenableFuture<Result> { if (hasPermissions()) { getLocation() } else { future.set(Result.failure()) } return future } } ListenableWorker
28. class LocationWorker(context : Context, params : WorkerParameters) : ListenableWorker(context, params) { val future = ResolvableFuture.create<Result>() override fun startWork(): ListenableFuture<Result> { if (hasPermissions()) { getLocation() } else { future.set(Result.failure()) } return future } } ListenableWorker Runs on main thread
29. class MyWorker(ctx: Context, params: WorkerParameters) : Worker(ctx, params) { override fun doWork(): Result { val in = inputData.getString(KEY_STRING) return try { // Do something that can fail Result.success(workDataOf(KEY_INT to 42)) } catch (throwable: Throwable) { // For errors, return FAILURE or RETRY Result.failure() } } } Worker
30. class MyWorker(ctx: Context, params: WorkerParameters) : Worker(ctx, params) { override fun doWork(): Result { val in = inputData.getString(KEY_STRING) return try { // Do something that can fail Result.success(workDataOf(KEY_INT to 42)) } catch (throwable: Throwable) { // For errors, return FAILURE or RETRY Result.failure() } } } Worker
31. class MyWorker(ctx: Context, params: WorkerParameters) : Worker(ctx, params) { override fun doWork(): Result { val in = inputData.getString(KEY_STRING) return try { // Do something that can fail Result.success(workDataOf(KEY_INT to 42)) } catch (throwable: Throwable) { // For errors, return FAILURE or RETRY Result.failure() } } } Worker Needs to be Synchronous
32. class RefreshMainDataWork(context: Context, params: WorkerParameters) : CoroutineWorker(context, params) { override suspend fun doWork(): Result { val database = getDatabase(applicationContext) val repository = TitleRepository(MainNetworkImpl, database.titleDao) return try { repository.refreshTitle() Result.success() } catch (error: TitleRefreshError) { Result.failure() } } } CoroutineWorker
33. class RefreshMainDataWork(context: Context, params: WorkerParameters) : CoroutineWorker(context, params) { override suspend fun doWork(): Result { val database = getDatabase(applicationContext) val repository = TitleRepository(MainNetworkImpl, database.titleDao) return try { repository.refreshTitle() Result.success() } catch (error: TitleRefreshError) { Result.failure() } } } CoroutineWorker
34. class RefreshMainDataWork(context: Context, params: WorkerParameters) : CoroutineWorker(context, params) { override suspend fun doWork(): Result { val database = getDatabase(applicationContext) val repository = TitleRepository(MainNetworkImpl, database.titleDao) return try { repository.refreshTitle() Result.success() } catch (error: TitleRefreshError) { Result.failure() } } } CoroutineWorker
35. dependencies { def work_version = "2.2.0" // (Java only) implementation "androidx.work:work-runtime:$work_version" // Kotlin + coroutines implementation "androidx.work:work-runtime-ktx:$work_version" // optional - RxJava2 support implementation "androidx.work:work-rxjava2:$work_version" // optional - GCMNetworkManager support implementation "androidx.work:work-gcm:$work_version" // optional - Test helpers androidTestImplementation "androidx.work:work-testing:$work_version" } WorkManager Dependencies
36. dependencies { def work_version = "2.2.0" // (Java only) implementation "androidx.work:work-runtime:$work_version" // Kotlin + coroutines implementation "androidx.work:work-runtime-ktx:$work_version" // optional - RxJava2 support implementation "androidx.work:work-rxjava2:$work_version" // optional - GCMNetworkManager support implementation "androidx.work:work-gcm:$work_version" // optional - Test helpers androidTestImplementation "androidx.work:work-testing:$work_version" } WorkManager Dependencies
37. dependencies { def work_version = "2.2.0" // (Java only) implementation "androidx.work:work-runtime:$work_version" // Kotlin + coroutines implementation "androidx.work:work-runtime-ktx:$work_version" // optional - RxJava2 support implementation "androidx.work:work-rxjava2:$work_version" // optional - GCMNetworkManager support implementation "androidx.work:work-gcm:$work_version" // optional - Test helpers androidTestImplementation "androidx.work:work-testing:$work_version" } WorkManager Dependencies
38. dependencies { def work_version = "2.2.0" // (Java only) implementation "androidx.work:work-runtime:$work_version" // Kotlin + coroutines implementation "androidx.work:work-runtime-ktx:$work_version" // optional - RxJava2 support implementation "androidx.work:work-rxjava2:$work_version" // optional - GCMNetworkManager support implementation "androidx.work:work-gcm:$work_version" // optional - Test helpers androidTestImplementation "androidx.work:work-testing:$work_version" } WorkManager Dependencies
39. dependencies { def work_version = "2.2.0" // (Java only) implementation "androidx.work:work-runtime:$work_version" // Kotlin + coroutines implementation "androidx.work:work-runtime-ktx:$work_version" // optional - RxJava2 support implementation "androidx.work:work-rxjava2:$work_version" // optional - GCMNetworkManager support implementation "androidx.work:work-gcm:$work_version" // optional - Test helpers androidTestImplementation "androidx.work:work-testing:$work_version" } WorkManager Dependencies
40. dependencies { def work_version = "2.2.0" // optional (but recommended) - Test helpers androidTestImplementation "androidx.work:work-testing:$work_version" // (Java only) implementation "androidx.work:work-runtime:$work_version" // Kotlin + coroutines implementation "androidx.work:work-runtime-ktx:$work_version" // optional - RxJava2 support implementation "androidx.work:work-rxjava2:$work_version" // optional - GCMNetworkManager support implementation "androidx.work:work-gcm:$work_version" } WorkManager Dependencies
41. How does WorkManager interact with Android?
42. class UploadWorker(appContext: Context, workerParams: WorkerParameters) : Worker(appContext, workerParams) { override fun doWork(): Result { uploadImages() return Result.success() } } val uploadWorkRequest = OneTimeWorkRequestBuilder<UploadWorker>() .setConstraints(constraints) .build() WorkManager.getInstance(myContext).enqueue(uploadWorkRequest) Enqueue a WorkRequest
43. Store in WorkManager Database How does WorkManager persist work?
44. JobScheduler Store in WorkManager Database How does WorkManager persist work? API 23+
45. JobScheduler Store in WorkManager Database How does WorkManager persist work? API 23+ Has Google Play and work-gcm? API 22-
46. JobScheduler Store in WorkManager Database GcmNetworkManager How does WorkManager persist work? API 23+ Has Google Play and work-gcm? Yes API 22-
47. JobScheduler Store in WorkManager Database GcmNetworkManager How does WorkManager persist work? API 23+ Has Google Play and work-gcm? AlarmManager Yes No API 22-
48. JobScheduler GcmNetworkManager How does WorkManager run your Work? AlarmManager GreedyScheduler Start app process (if needed) Ask WorkManager to Run Work
49. JobScheduler GcmNetworkManager AlarmManager GreedyScheduler Start app process (if needed) Ask WorkManager to Run Work How does WorkManager run your Work?
50. Observe Work
51. val save = OneTimeWorkRequestBuilder<SaveImageWorker>() .addTag(TAG_SAVE) .build() WorkManager’s WorkRequest
52. val save = OneTimeWorkRequestBuilder<SaveImageWorker>() .addTag(TAG_SAVE) .build() WorkManager.getInstance().getWorkInfoById(save.id) WorkInfo from UUID WorkManager.getInstance().getWorkInfoByIdLiveData(save.id)
53. val save = OneTimeWorkRequestBuilder<SaveImageWorker>() .addTag(TAG_SAVE) .build() WorkManager.getInstance().getWorkInfoById(save.id) WorkInfo from UUID WorkManager.getInstance().getWorkInfoByIdLiveData(save.id)
54. val save = OneTimeWorkRequestBuilder<SaveImageWorker>() .addTag(TAG_SAVE) .build() WorkManager.getInstance().getWorkInfoById(save.id) WorkInfo(s) from TAG WorkManager.getInstance().getWorkInfoByIdLiveData(save.id) WorkManager.getInstance().getWorkInfosByTag(TAG_SAVE) WorkManager.getInstance().getWorkInfosByTagLiveData(TAG_SAVE)
55. val save = OneTimeWorkRequestBuilder<SaveImageWorker>() .addTag(TAG_SAVE) .build() WorkManager.getInstance().getWorkInfoById(save.id) WorkInfo(s) from TAG WorkManager.getInstance().getWorkInfoByIdLiveData(save.id) WorkManager.getInstance().getWorkInfosByTag(TAG_SAVE) WorkManager.getInstance().getWorkInfosByTagLiveData(TAG_SAVE)
56. BLOCKED Life of OneTimeWorkRequest
57. BLOCKED ENQUEUED Life of OneTimeWorkRequest
58. BLOCKED ENQUEUED Life of OneTimeWorkRequest RUNNING
59. BLOCKED ENQUEUED Life of OneTimeWorkRequest RUNNING SUCCEEDED SUCCESS
60. BLOCKED ENQUEUED Life of OneTimeWorkRequest RUNNING SUCCEEDED CANCELLED SUCCESS RETRY
61. BLOCKED ENQUEUED Life of OneTimeWorkRequest RUNNING SUCCEEDED FAILED CANCELLED SUCCESS FAILURE RETRY
62. BLOCKED ENQUEUED Life of OneTimeWorkRequest RUNNING SUCCEEDED FAILED CANCELLED CANCEL SUCCESS FAILURE RETRY
63. ENQUEUED Life of PeriodicWorkRequest
64. ENQUEUED Life of PeriodicWorkRequest RUNNING
65. ENQUEUED Life of PeriodicWorkRequest RUNNING SUCCESS
66. SUCCESS, RETRY ENQUEUED Life of PeriodicWorkRequest RUNNING SUCCESS
67. SUCCESS, RETRY SUCCESS, RETRY, FAILURE ENQUEUED Life of PeriodicWorkRequest RUNNING SUCCESS
68. SUCCESS, RETRY SUCCESS, RETRY, FAILURE ENQUEUED Life of PeriodicWorkRequest RUNNING CANCELLED CANCEL SUCCESS
69. Life of a chain of work If a unit of work fails, all dependent work is marked as FAILED
70. Life of a chain of work If a unit of work fails, all dependent work is marked as FAILED If a unit of work is cancelled, all dependent work is marked as CANCELLED
71. Cancel Work and Handling Stoppages
72. val save = OneTimeWorkRequestBuilder<SaveImageWorker>() .addTag(TAG_SAVE) .build() WorkManager’s WorkRequest
73. val save = OneTimeWorkRequestBuilder<SaveImageWorker>() .addTag(TAG_SAVE) .build() WorkManager.getInstance().cancelWorkById(save.id) Cancel Work from UUID
74. val save = OneTimeWorkRequestBuilder<SaveImageWorker>() .addTag(TAG_SAVE) .build() WorkManager.getInstance().cancelWorkById(save.id) Cancel Work from TAG WorkManager.getInstance().cancelAllWorkByTag(TAG_SAVE)
75. class MyWorker(ctx: Context, params: WorkerParameters) : Worker(ctx, params) { override fun doWork(): Result { val in = inputData.getString(KEY_STRING) return try { // Do something that can fail if (isStopped()) return Result.failure() Result.success(workDataOf(KEY_INT to 42)) } catch (throwable: Throwable) { // For errors, return FAILURE or RETRY Result.failure() } } } Handle Stopping Work
76. class MyWorker(ctx: Context, params: WorkerParameters) : Worker(ctx, params) { override fun doWork(): Result { val in = inputData.getString(KEY_STRING) return try { // Do something that can fail if (isStopped()) return Result.failure() Result.success(workDataOf(KEY_INT to 42)) } catch (throwable: Throwable) { // For errors, return FAILURE or RETRY Result.failure() } } } Handling Stoppages
77. class MyWorker(ctx: Context, params: WorkerParameters) : Worker(ctx, params) { override fun doWork(): Result { val in = inputData.getString(KEY_STRING) return try { // Do something that can fail if (isStopped()) return Result.success() // this is not used Result.success(workDataOf(KEY_INT to 42)) } catch (throwable: Throwable) { // For errors, return FAILURE or RETRY Result.failure() } } } Handling Stoppages
78. class MyWorker(ctx: Context, params: WorkerParameters) : Worker(ctx, params) { override fun doWork(): Result { // … } override fun onStopped() { super.onStopped() // Cleanup } } Handling Stoppages
79. class MyWorker(ctx: Context, params: WorkerParameters) : Worker(ctx, params) { override fun doWork(): Result { // … } override fun onStopped() { super.onStopped() // Cleanup } } Handling Stoppages
80. Testing
81. @Before fun setup() { context = ApplicationProvider.getApplicationContext() workManager = WorkManager.getInstance(context) } @Test fun testRefreshMainDataWork() { val worker = TestListenableWorkerBuilder<TestWorker>(context).build() val result = worker.startWork().get() assertThat(result, `is` (Result.success())) } TestListenableWorkerBuilder (v2.1)
82. @Before fun setup() { context = ApplicationProvider.getApplicationContext() workManager = WorkManager.getInstance(context) } @Test fun testRefreshMainDataWork() { val worker = TestListenableWorkerBuilder<TestWorker>(context).build() val result = worker.startWork().get() assertThat(result, `is` (Result.success())) } Build your Worker
83. @Before fun setup() { context = ApplicationProvider.getApplicationContext() workManager = WorkManager.getInstance(context) } @Test fun testRefreshMainDataWork() { val worker = TestListenableWorkerBuilder<TestWorker>(context).build() val result = worker.startWork().get() assertThat(result, `is` (Result.success())) } Directly invoke your Work
84. @Before fun setup() { context = ApplicationProvider.getApplicationContext() workManager = WorkManager.getInstance(context) } @Test fun testRefreshMainDataWork() { val worker = TestListenableWorkerBuilder<TestWorker>(context).build() val result = worker.startWork().get() assertThat(result, `is` (Result.success())) } Test!
85. @Test fun testMyWorkRetry() { val data = workDataOf("SERVER_URL" to "http://fake.url") // Get the ListenableWorker with a RunAttemptCount of 2 val worker = TestListenableWorkerBuilder<MyWork>(context) .setInputData(data) .setRunAttemptCount(2) .build() // Start the work synchronously val result = worker.startWork().get() assertThat(result, `is`(Result.retry())) } TestListenableWorkerBuilder (v2.1)
86. @Test fun testMyWorkRetry() { val data = workDataOf("SERVER_URL" to "http://fake.url") // Get the ListenableWorker with a RunAttemptCount of 2 val worker = TestListenableWorkerBuilder<MyWork>(context) .setInputData(data) .setRunAttemptCount(2) .build() // Start the work synchronously val result = worker.startWork().get() assertThat(result, `is`(Result.retry())) } Test Work with input data
87. @Test fun testMyWorkRetry() { val data = workDataOf("SERVER_URL" to "http://fake.url") // Get the ListenableWorker with a RunAttemptCount of 2 val worker = TestListenableWorkerBuilder<MyWork>(context) .setInputData(data) .setRunAttemptCount(2) .build() // Start the work synchronously val result = worker.startWork().get() assertThat(result, `is`(Result.retry())) } Test Work for Retry behaviour
88. @Test fun testMyWorkRetry() { val data = workDataOf("SERVER_URL" to "http://fake.url") // Get the ListenableWorker with a RunAttemptCount of 2 val worker = TestListenableWorkerBuilder<MyWork>(context) .setInputData(data) .setRunAttemptCount(2) .build() // Start the work synchronously val result = worker.startWork().get() assertThat(result, `is`(Result.retry())) } Test Work for Retry behaviour
89. Where to go… ... from here?
90. Resources: Just Starting? --> Codelab: codelabs.developers.google.com/codelabs/android-workmanager-kt/ Want to deep dive? --> Documentation: d.android.com/topic/libraries/architecture/workmanager/ I know what I’m doing! --> Release Notes: d.android.com/jetpack/androidx/releases/work bit.ly/pfm-wm-devfest19
91. More Resources: Videos: - ADS2018 - Working with WorkManager - ADS2019 - WorkManager: Beyond the Basics Medium Blogs: - Introducing WorkManager - WorkManager Basics - WorkManager Periodicity - WorkManager meets Kotlin - More coming... bit.ly/pfm-wm-devfest19
92. THANKS! Pietro Maggi, @pfmaggi bit.ly/pfm-wm-devfest19