Android WorkManager: Which process does work actually execute in?

Question

I am using the WorkManager API that is supposed to be able to run even while the app isn't started or is killed(?) Then I wonder, if app isn't started or is killed, which process does the work actually execute in? Some system process? Or is it actually (by default) always running in a designated thread in the app process if nothing else is specified? I am confused. If it is running in the app process, does it start the app process without actually starting anything else in it, then?

I am curious to whether I can access my app's data from within the work while it is executing. I mean I am not supposed to be able to access for instance a singleton app member in case it is running in a completely separate process.

Answer 1

it looks like they added multi-process support in version 2.5.0

• see release notes for work manager version 2.5.0

steps to run worker in another process

1. need to call setDefaultProcessName

   fun getRemoteWorkManager(context:Context):RemoteWorkManager
   {
       if (!WorkManager.isInitialized())
       {
           val configuration = Configuration.Builder()
               .setDefaultProcessName(":name_of_process")
               .build()
           WorkManager.initialize(context,configuration)
       }
       return RemoteWorkManager.getInstance(context)
   }
   

2. need to disable the existing WorkManagerInitializer by adding below into your AndroidManifest.xml

   <manifest>
       <application>
           <provider
               android:name="androidx.startup.InitializationProvider"
               android:authorities="${applicationId}.androidx-startup"
               android:exported="false"
               tools:node="merge" >
               <meta-data
                   android:name="androidx.work.WorkManagerInitializer"
                   android:value="androidx.startup"
                   tools:node="remove" />
           </provider>
       </application>
   </manifest>
   

3. need to enqueue work using RemoteWorkManager instead of WorkManager
4. need to declare a new dependency to use multi-process support

   // optional - Multiprocess support
   implementation "androidx.work:work-multiprocess:$work_version"
   

5. as per this answer, need to set the process that you want to use in the manifest for the following services

   <service
       android:name="androidx.work.multiprocess.RemoteWorkManagerService"
       tools:replace="android:process"
       android:process=":name_of_process"/>
   
   <service
       android:name="androidx.work.impl.background.systemjob.SystemJobService"
       tools:replace="android:process"
       android:process=":name_of_process"/>