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

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2. Embracing WorkManager
   Pietro Maggi | Android DevRel Engineer @ Google
   bit.ly/pfm-wm-devfest19
   

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3. The basics
   ..or what is WorkManager
   

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4. Part of Android Jetpack
   Accelerate
   development
   Eliminate
   boilerplate code
   Build high quality,
   robust apps
   

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5. WorkManager is an Android library that runs
   deferrable background work when the constraints
   are satisfied.
   WorkManager
   

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6. WorkManager is an Android library that runs
   deferrable background work when the constraints
   are satisfied.
   WorkManager
   

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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
   

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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
   

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9. ● Asynchronous one-off and periodic tasks
   WorkManager Benefits
   Compress
   

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10. ● Asynchronous one-off and periodic tasks
    ● Chaining with Input/Output
    WorkManager Benefits
    Upload
    Compress
    Filter Image 2 Filter Image 3
    Filter Image 1
    

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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
    

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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
    

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13. I need to run a task
    

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14. Has to finish?
    I need to run a task
    

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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
    

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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
    

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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
    

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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
    

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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
    

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20. Release History
    1.0 / 2.0
    Initial release in support lib (1.0) / AndroidX (2.0)
    1.0 / 2.0
    

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21. Release History
    1.0 / 2.0
    On-demand initialization, new testing support
    2.1
    2.1
    

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22. Release History Present
    GcmNetworkManager support (API 22 and below)
    2.1 2.2
    1.0 / 2.0
    

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23. Release History Future
    Progress and setForeground APIs
    2.1 2.3
    1.0 / 2.0 2.2
    

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24. WorkManager’s
    Worker classes
    

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25. ListenableWorker
    Worker
    Meet the Worker Family!
    RxWorker CoroutineWorker*
    *Only available using Kotlin
    

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26. class LocationWorker(context : Context, params : WorkerParameters)
    : ListenableWorker(context, params) {
    val future = ResolvableFuture.create()
    override fun startWork(): ListenableFuture {
    if (hasPermissions()) {
    getLocation()
    } else {
    future.set(Result.failure())
    }
    return future
    }
    }
    ListenableWorker
    

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27. class LocationWorker(context : Context, params : WorkerParameters)
    : ListenableWorker(context, params) {
    val future = ResolvableFuture.create()
    override fun startWork(): ListenableFuture {
    if (hasPermissions()) {
    getLocation()
    } else {
    future.set(Result.failure())
    }
    return future
    }
    }
    ListenableWorker
    

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28. class LocationWorker(context : Context, params : WorkerParameters)
    : ListenableWorker(context, params) {
    val future = ResolvableFuture.create()
    override fun startWork(): ListenableFuture {
    if (hasPermissions()) {
    getLocation()
    } else {
    future.set(Result.failure())
    }
    return future
    }
    }
    ListenableWorker
    Runs on
    main thread
    

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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
    

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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
    

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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
    

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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
    

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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
    

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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
    

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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
    

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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
    

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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
    

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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
    

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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
    

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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
    

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41. How does
    WorkManager
    interact with
    Android?
    

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42. class UploadWorker(appContext: Context, workerParams: WorkerParameters)
    : Worker(appContext, workerParams) {
    override fun doWork(): Result {
    uploadImages()
    return Result.success()
    }
    }
    val uploadWorkRequest = OneTimeWorkRequestBuilder()
    .setConstraints(constraints)
    .build()
    WorkManager.getInstance(myContext).enqueue(uploadWorkRequest)
    Enqueue a WorkRequest
    

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43. Store in WorkManager Database
    How does WorkManager persist work?
    

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44. JobScheduler
    Store in WorkManager Database
    How does WorkManager persist work?
    API 23+
    

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45. JobScheduler
    Store in WorkManager Database
    How does WorkManager persist work?
    API 23+
    Has Google Play and work-gcm?
    API 22-
    

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46. JobScheduler
    Store in WorkManager Database
    GcmNetworkManager
    How does WorkManager persist work?
    API 23+
    Has Google Play and work-gcm?
    Yes
    API 22-
    

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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-
    

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48. JobScheduler
    GcmNetworkManager
    How does WorkManager run your Work?
    AlarmManager
    GreedyScheduler
    Start app process
    (if needed)
    Ask WorkManager
    to Run Work
    

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49. JobScheduler
    GcmNetworkManager
    AlarmManager
    GreedyScheduler
    Start app process
    (if needed)
    Ask WorkManager
    to Run Work
    How does WorkManager run your Work?
    

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50. Observe Work
    

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51. val save = OneTimeWorkRequestBuilder()
    .addTag(TAG_SAVE)
    .build()
    WorkManager’s WorkRequest
    

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52. val save = OneTimeWorkRequestBuilder()
    .addTag(TAG_SAVE)
    .build()
    WorkManager.getInstance().getWorkInfoById(save.id)
    WorkInfo from UUID
    WorkManager.getInstance().getWorkInfoByIdLiveData(save.id)
    

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53. val save = OneTimeWorkRequestBuilder()
    .addTag(TAG_SAVE)
    .build()
    WorkManager.getInstance().getWorkInfoById(save.id)
    WorkInfo from UUID
    WorkManager.getInstance().getWorkInfoByIdLiveData(save.id)
    

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54. val save = OneTimeWorkRequestBuilder()
    .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)
    

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55. val save = OneTimeWorkRequestBuilder()
    .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)
    

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56. BLOCKED
    Life of OneTimeWorkRequest
    

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57. BLOCKED ENQUEUED
    Life of OneTimeWorkRequest
    

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58. BLOCKED ENQUEUED
    Life of OneTimeWorkRequest
    RUNNING
    

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59. BLOCKED ENQUEUED
    Life of OneTimeWorkRequest
    RUNNING SUCCEEDED
    SUCCESS
    

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60. BLOCKED ENQUEUED
    Life of OneTimeWorkRequest
    RUNNING SUCCEEDED
    CANCELLED
    SUCCESS
    RETRY
    

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61. BLOCKED ENQUEUED
    Life of OneTimeWorkRequest
    RUNNING SUCCEEDED
    FAILED
    CANCELLED
    SUCCESS
    FAILURE
    RETRY
    

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62. BLOCKED ENQUEUED
    Life of OneTimeWorkRequest
    RUNNING SUCCEEDED
    FAILED
    CANCELLED
    CANCEL
    SUCCESS
    FAILURE
    RETRY
    

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63. ENQUEUED
    Life of PeriodicWorkRequest
    

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64. ENQUEUED
    Life of PeriodicWorkRequest
    RUNNING
    

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65. ENQUEUED
    Life of PeriodicWorkRequest
    RUNNING
    SUCCESS
    

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66. SUCCESS, RETRY
    ENQUEUED
    Life of PeriodicWorkRequest
    RUNNING
    SUCCESS
    

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67. SUCCESS, RETRY
    SUCCESS, RETRY, FAILURE
    ENQUEUED
    Life of PeriodicWorkRequest
    RUNNING
    SUCCESS
    

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68. SUCCESS, RETRY
    SUCCESS, RETRY, FAILURE
    ENQUEUED
    Life of PeriodicWorkRequest
    RUNNING
    CANCELLED
    CANCEL
    SUCCESS
    

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69. Life of a chain of work
    If a unit of work fails, all dependent work is marked as
    FAILED
    

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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
    

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71. Cancel Work and
    Handling Stoppages
    

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72. val save = OneTimeWorkRequestBuilder()
    .addTag(TAG_SAVE)
    .build()
    WorkManager’s WorkRequest
    

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73. val save = OneTimeWorkRequestBuilder()
    .addTag(TAG_SAVE)
    .build()
    WorkManager.getInstance().cancelWorkById(save.id)
    Cancel Work from UUID
    

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74. val save = OneTimeWorkRequestBuilder()
    .addTag(TAG_SAVE)
    .build()
    WorkManager.getInstance().cancelWorkById(save.id)
    Cancel Work from TAG
    WorkManager.getInstance().cancelAllWorkByTag(TAG_SAVE)
    

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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
    

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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
    

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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
    

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78. class MyWorker(ctx: Context, params: WorkerParameters) : Worker(ctx, params) {
    override fun doWork(): Result {
    // …
    }
    override fun onStopped() {
    super.onStopped()
    // Cleanup
    }
    }
    Handling Stoppages
    

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79. class MyWorker(ctx: Context, params: WorkerParameters) : Worker(ctx, params) {
    override fun doWork(): Result {
    // …
    }
    override fun onStopped() {
    super.onStopped()
    // Cleanup
    }
    }
    Handling Stoppages
    

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80. Testing
    

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81. @Before
    fun setup() {
    context = ApplicationProvider.getApplicationContext()
    workManager = WorkManager.getInstance(context)
    }
    @Test
    fun testRefreshMainDataWork() {
    val worker = TestListenableWorkerBuilder(context).build()
    val result = worker.startWork().get()
    assertThat(result, `is` (Result.success()))
    }
    TestListenableWorkerBuilder (v2.1)
    

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82. @Before
    fun setup() {
    context = ApplicationProvider.getApplicationContext()
    workManager = WorkManager.getInstance(context)
    }
    @Test
    fun testRefreshMainDataWork() {
    val worker = TestListenableWorkerBuilder(context).build()
    val result = worker.startWork().get()
    assertThat(result, `is` (Result.success()))
    }
    Build your Worker
    

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83. @Before
    fun setup() {
    context = ApplicationProvider.getApplicationContext()
    workManager = WorkManager.getInstance(context)
    }
    @Test
    fun testRefreshMainDataWork() {
    val worker = TestListenableWorkerBuilder(context).build()
    val result = worker.startWork().get()
    assertThat(result, `is` (Result.success()))
    }
    Directly invoke your Work
    

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84. @Before
    fun setup() {
    context = ApplicationProvider.getApplicationContext()
    workManager = WorkManager.getInstance(context)
    }
    @Test
    fun testRefreshMainDataWork() {
    val worker = TestListenableWorkerBuilder(context).build()
    val result = worker.startWork().get()
    assertThat(result, `is` (Result.success()))
    }
    Test!
    

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85. @Test
    fun testMyWorkRetry() {
    val data = workDataOf("SERVER_URL" to "http://fake.url")
    // Get the ListenableWorker with a RunAttemptCount of 2
    val worker = TestListenableWorkerBuilder(context)
    .setInputData(data)
    .setRunAttemptCount(2)
    .build()
    // Start the work synchronously
    val result = worker.startWork().get()
    assertThat(result, `is`(Result.retry()))
    }
    TestListenableWorkerBuilder (v2.1)
    

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86. @Test
    fun testMyWorkRetry() {
    val data = workDataOf("SERVER_URL" to "http://fake.url")
    // Get the ListenableWorker with a RunAttemptCount of 2
    val worker = TestListenableWorkerBuilder(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
    

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87. @Test
    fun testMyWorkRetry() {
    val data = workDataOf("SERVER_URL" to "http://fake.url")
    // Get the ListenableWorker with a RunAttemptCount of 2
    val worker = TestListenableWorkerBuilder(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
    

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88. @Test
    fun testMyWorkRetry() {
    val data = workDataOf("SERVER_URL" to "http://fake.url")
    // Get the ListenableWorker with a RunAttemptCount of 2
    val worker = TestListenableWorkerBuilder(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
    

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89. Where to go…
    ... from here?
    

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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
    

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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
    

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92. THANKS!
    Pietro Maggi, @pfmaggi
    bit.ly/pfm-wm-devfest19
    

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