How to disable all but FCM

[root...@gmail.com]

Hey Firebase team,

I am currently migrating an app from GCM to FCM. The need for cloud messaging is the only reason I need Firebase, I don't need any other firebase services.

Here's what I've done to obtain the minimal setup:

1) only include 'core' and 'fcm' modules in gradle files:

    implementation 'com.google.firebase:firebase-core:16.0.3'

    implementation 'com.google.firebase:firebase-messaging:17.3.1'

2) **avoid** using google-services plugin and google-services.json file

    // classpath 'com.google.gms:google-services:4.0.1'

    // apply plugin: 'com.google.gms.google-services'

3) disable FirebaseInitProvider and do initialize Firebase manually:

    // in AndroidManifest.xml

    <provider

        android:name="com.google.firebase.provider.FirebaseInitProvider"

        android:authorities="${applicationId}.firebaseinitprovider"

        android:exported="false"

        tools:node="remove"

        />

    // in Application class

    val firebaseOptions = FirebaseOptions.Builder()

        .setApplicationId("**masked**")

        .setGcmSenderId(**masked**)

        .build()

    FirebaseApp.initializeApp(this, firebaseOptions)

4) disable analytics from manifest as per docs for disabling Firebase Analytics:

    <meta-data

        android:name="firebase_analytics_collection_deactivated"

        android:value="true"

        />

    <meta-data

        android:name="google_analytics_adid_collection_enabled"

        android:value="false"

        />

5) remove receivers and serivces automerged from firebase-analytics's AndroidManifest:

    <receiver

        android:name="com.google.android.gms.measurement.AppMeasurementInstallReferrerReceiver"

        tools:node="remove"

        />

    <receiver

        android:name="com.google.android.gms.measurement.AppMeasurementReceiver"

        tools:node="remove"

        />

    <service

        android:name="com.google.android.gms.measurement.AppMeasurementService"

        tools:node="remove"

        />

    <service

        android:name="com.google.android.gms.measurement.AppMeasurementJobService"

        tools:node="remove"

        />

With all the steps FCM push notifications do work correctly. 

However, as I see from verbose logging

    adb shell setprop log.tag.FA VERBOSE

    adb shell setprop debug.firebase.analytics.app <package-name>

Firebase still subscribes for lifecycle callbacks and lives its life there quite active:

09-12 16:58:31.032 5165-5165 V/FA: Registered activity lifecycle callback

09-12 16:58:31.141 5165-5202 I/FA: Collection disabled with firebase_analytics_collection_deactivated=1

09-12 16:58:31.180 5165-5202 I/FA: App measurement is starting up, version: 13001

    To enable debug logging run: adb shell setprop log.tag.FA VERBOSE

09-12 16:58:31.212 5165-5202 I/FA: Faster debug mode event logging enabled. To disable, run:

      adb shell setprop debug.firebase.analytics.app .none.

09-12 16:58:31.212 5165-5202 D/FA: Debug-level message logging enabled

09-12 16:58:33.061 5165-5165 V/FA: onActivityCreated

09-12 16:58:33.319 5165-5202 D/FA: Event not sent since app measurement is disabled

09-12 16:58:33.324 5165-5202 V/FA: Connecting to remote service

09-12 16:58:33.390 5165-5202 V/FA: Activity resumed, time: 1188927

09-12 16:58:33.761 5165-5202 V/FA: Screen exposed for less than 1000 ms. Event not sent. time: 446

09-12 16:58:33.783 5165-5202 V/FA: Connection attempt already in progress

09-12 16:58:33.785 5165-5202 V/FA: Activity paused, time: 1189366

09-12 16:58:34.037 5165-5165 V/FA: onActivityCreated

09-12 16:58:34.603 5165-5202 D/FA: Event not sent since app measurement is disabled

09-12 16:58:34.604 5165-5202 V/FA: Connection attempt already in progress

09-12 16:58:34.620 5165-5202 V/FA: Activity resumed, time: 1190181

09-12 16:58:34.841 5165-5202 D/FA: Connected to remote service

09-12 16:58:34.869 5165-5202 V/FA: Processing queued up service tasks: 3

09-12 16:58:35.772 5165-5165 V/FA: onActivityCreated

09-12 16:58:35.774 5165-5202 V/FA: Recording user engagement, ms: 1197

09-12 16:58:35.791 5165-5202 V/FA: Activity paused, time: 1191378

09-12 16:58:35.805 5165-5202 D/FA: Event not sent since app measurement is disabled

09-12 16:58:36.139 5165-5202 D/FA: Event not sent since app measurement is disabled

09-12 16:58:36.155 5165-5202 V/FA: Activity resumed, time: 1191724

What bothers me is that, while it does not send the analytics to the Firebase backend (I hope so), it is still performing a lot of work locally wasting the CPU. 

What is the worst part of the story is that I have no option of opting out in case I want to use push messages.

Is there an undocumented way of disabling this background activity?

If not, is there any other way to get push notifications working without applying Firebase?