Disable firebase logging for google ML Kit library in android

Question

Could anyone help me to tell how can I disable the firebase logging in Google ML Kit library for android. For every 15 mins it will POST some information to https://firebaselogging.googleapis.com/v0cc/log/batch?format=json_proto3

I tried using the recommendation from google https://firebase.google.com/docs/perf-mon/disable-sdk?platform=android#kotlin+ktx and I am also not sure whether it is a right way.

Suggestions are welcome.

Answer 1

Google's guide from the question didn't work for me, so I have looked for alternatives.

The library is obfuscated, so it is hard to be sure, but it appears that the logging is hardcoded in. However, there is a very hacky way to disable it through some fragile reflection:

import android.util.Log
import com.google.mlkit.common.sdkinternal.LazyInstanceMap
import java.lang.reflect.Field

/**
 * This class tries to disable MLKit's phoning home/logging.
 * This is extremely hacky and will probably break in the next update (obfuscated class names will probably need renaming).
 *
 * This class exploits the fact, that there are multiple options classes which control this
 * (look for "MLKitLoggingOptions" in toString implementation) and for some reason MLKit uses them as keys
 * in LazyInstanceMaps which exist as static (usually) variables (which are themselves lazy).
 *
 * This makes sure that the LazyInstanceMaps exist, then it hijacks their internal HashMap implementation
 * and replaces it with a custom map, that creates instances of whatever with logging disabled.
 *
 * The way to detect which holder classes need renaming, look at the stack trace, for example:
 * ```
    java.lang.NoClassDefFoundError: Failed resolution of: Lcom/google/android/datatransport/cct/CCTDestination;
    at com.google.android.gms.internal.mlkit_vision_barcode.zznu.<init>(com.google.android.gms:play-services-mlkit-barcode-scanning@@18.0.0:1)
    at com.google.android.gms.internal.mlkit_vision_barcode.zznf.<init>(com.google.android.gms:play-services-mlkit-barcode-scanning@@18.0.0:3)
    at com.google.android.gms.internal.mlkit_vision_barcode.zznw.create(com.google.android.gms:play-services-mlkit-barcode-scanning@@18.0.0:4)
    at com.google.mlkit.common.sdkinternal.LazyInstanceMap.get(com.google.mlkit:common@@18.0.0:3)
    at com.google.android.gms.internal.mlkit_vision_barcode.zznx.zza(com.google.android.gms:play-services-mlkit-barcode-scanning@@18.0.0:2)
    at com.google.android.gms.internal.mlkit_vision_barcode.zznx.zzb(com.google.android.gms:play-services-mlkit-barcode-scanning@@18.0.0:3)
    at com.google.mlkit.vision.barcode.internal.zzf.create(com.google.android.gms:play-services-mlkit-barcode-scanning@@18.0.0:3)
    at com.google.mlkit.common.sdkinternal.LazyInstanceMap.get(com.google.mlkit:common@@18.0.0:3)
    at com.google.mlkit.vision.barcode.internal.zze.zzb(com.google.android.gms:play-services-mlkit-barcode-scanning@@18.0.0:2)
    at com.google.mlkit.vision.barcode.BarcodeScanning.getClient(com.google.android.gms:play-services-mlkit-barcode-scanning@@18.0.0:3)
 * ```
 * here are two LazyInstanceMap lookups, of which only the second one (through trial and error or with debugger)
 * uses MLKitLoggingOptions keys. From here we can find that the holder class is com.google.android.gms.internal.mlkit_vision_barcode.zznx .
 */
object MLKitTrickery {

    private class mlkit_vision_barcodeLoggingOptions(base: com.google.android.gms.internal.mlkit_vision_barcode.zzne) : com.google.android.gms.internal.mlkit_vision_barcode.zzne() {
        private val libraryName: String = base.zzb()
        private val firelogEventType: Int = base.zza()
        override fun zza(): Int = firelogEventType
        override fun zzb(): String = libraryName
        override fun zzc(): Boolean = false //enableFirelog

        override fun equals(other: Any?): Boolean {
            if (this === other) return true
            if (javaClass != other?.javaClass) return false

            other as mlkit_vision_barcodeLoggingOptions
            if (libraryName != other.libraryName) return false
            if (firelogEventType != other.firelogEventType) return false
            return true
        }

        override fun hashCode(): Int {
            var result = libraryName.hashCode()
            result = 31 * result + firelogEventType
            return result
        }
    }

    private class mlkit_vision_commonLoggingOptions(base: com.google.android.gms.internal.mlkit_vision_common.zzjn) : com.google.android.gms.internal.mlkit_vision_common.zzjn() {
        private val libraryName: String = base.zzb()
        private val firelogEventType: Int = base.zza()
        override fun zza(): Int = firelogEventType
        override fun zzb(): String = libraryName
        override fun zzc(): Boolean = false //enableFirelog

        override fun equals(other: Any?): Boolean {
            if (this === other) return true
            if (javaClass != other?.javaClass) return false

            other as mlkit_vision_commonLoggingOptions
            if (libraryName != other.libraryName) return false
            if (firelogEventType != other.firelogEventType) return false
            return true
        }

        override fun hashCode(): Int {
            var result = libraryName.hashCode()
            result = 31 * result + firelogEventType
            return result
        }
    }

    private fun isMLKitLoggingOptions(obj: Any): Boolean {
        return obj is com.google.android.gms.internal.mlkit_vision_barcode.zzne
                || obj is com.google.android.gms.internal.mlkit_vision_common.zzjn
    }

    private fun convertMLKitLoggingOptions(obj: Any): Any? {
        if (obj is com.google.android.gms.internal.mlkit_vision_barcode.zzne) {
            return mlkit_vision_barcodeLoggingOptions(obj)
        }
        if (obj is com.google.android.gms.internal.mlkit_vision_common.zzjn) {
            return mlkit_vision_commonLoggingOptions(obj)
        }
        return null
    }

    @Suppress("UNCHECKED_CAST")
    private fun patchLazyMap(lazyMapHolder:Any?, lazyMapHolderClass: Class<*>) {
        val holderField = lazyMapHolderClass.declaredFields.find { LazyInstanceMap::class.java.isAssignableFrom(it.type) }!!
        var currentLazyInstanceMap = holderField.get(lazyMapHolder)
        if (currentLazyInstanceMap == null) {
            var lastError: Throwable? = null
            for (constructor in holderField.type.declaredConstructors) {
                try {
                    constructor.isAccessible = true
                    val params = arrayOfNulls<Any?>(constructor.parameterCount)
                    currentLazyInstanceMap = constructor.newInstance(*params)
                    holderField.set(lazyMapHolder, currentLazyInstanceMap)
                } catch (e:Throwable) {
                    lastError = e
                }
            }
            if (currentLazyInstanceMap == null) {
                throw java.lang.Exception("Failed to initialize LazyInstanceMap "+holderField.type, lastError)
            }
        }

        var mapHolderClass: Class<*> = currentLazyInstanceMap.javaClass
        val createMethod = mapHolderClass.getDeclaredMethod("create", Object::class.java)

        val mapField: Field
        while (true) {
            val mapFieldCandidate = mapHolderClass.declaredFields.firstOrNull { Map::class.java.isAssignableFrom(it.type) }
            if (mapFieldCandidate != null) {
                mapField = mapFieldCandidate
                break
            }
            mapHolderClass = mapHolderClass.superclass ?: error("It appears that ${currentLazyInstanceMap.javaClass} does not have a backing map field")
        }

        val oldMap = mapField.get(currentLazyInstanceMap) as MutableMap<Any, Any?>
        val customMap = object : MutableMap<Any, Any?> by oldMap {

            override fun containsKey(key: Any): Boolean {
                if (oldMap.containsKey(key)) {
                    return true
                }
                if (isMLKitLoggingOptions(key)) {
                    return true
                }
                return false
            }

            override fun get(key: Any): Any? {
                val existing = oldMap.get(key)
                if (existing != null) {
                    return existing
                }

                val convertedKey = convertMLKitLoggingOptions(key)
                if (convertedKey != null) {
                    val created = createMethod.invoke(currentLazyInstanceMap, convertedKey)
                    oldMap.put(key, created)
                    return created
                }

                return null
            }
        }
        mapField.isAccessible = true
        mapField.set(currentLazyInstanceMap, customMap)
    }

    private var initialized = false

    /**
     * Call this to attempt to disable MLKit logging.
     */
    fun init() {
        try {
            patchLazyMap(null, com.google.android.gms.internal.mlkit_vision_barcode.zznx::class.java)
            patchLazyMap(null, com.google.android.gms.internal.mlkit_vision_common.zzkc::class.java)
            initialized = true
        } catch (e: Throwable) {
            Log.e("MLKitTrickery", "Failed to disable MLKit phoning home")
        }
    }
}

When you also shim out GMS TelemetryLogging with:

@file:Suppress("unused", "UNUSED_PARAMETER")

package com.google.android.gms.common.internal

import android.app.Activity
import android.content.Context
import android.os.Parcel
import com.google.android.gms.tasks.OnFailureListener
import com.google.android.gms.tasks.OnSuccessListener
import com.google.android.gms.tasks.Task
import java.util.concurrent.Executor

class TelemetryLoggingOptions {
    class Builder {
        fun setApi(api: String?): Builder = this
        fun build(): TelemetryLoggingOptions = TelemetryLoggingOptions()
    }

    companion object {
        @JvmStatic
        fun builder(): Builder = Builder()
    }
}

private object DummyLogTask : Task<Void?>() {
    override fun addOnFailureListener(p0: OnFailureListener): Task<Void?> {
        // Implemented, because failing tells MLKit to back-off for 30 minutes, which is a win for performance
        p0.onFailure(exception)
        return this
    }
    override fun addOnFailureListener(p0: Activity, p1: OnFailureListener): Task<Void?> = addOnFailureListener(p1)
    override fun addOnFailureListener(p0: Executor, p1: OnFailureListener): Task<Void?> = addOnFailureListener(p1)

    override fun addOnSuccessListener(p0: OnSuccessListener<in Void?>): Task<Void?> = this
    override fun addOnSuccessListener(p0: Activity, p1: OnSuccessListener<in Void?>): Task<Void?> = addOnSuccessListener(p1)
    override fun addOnSuccessListener(p0: Executor, p1: OnSuccessListener<in Void?>): Task<Void?> = addOnSuccessListener(p1)

    override fun getException(): Exception? = exception
    override fun getResult(): Void? = null
    override fun <X : Throwable?> getResult(p0: Class<X>): Void? = null

    override fun isCanceled(): Boolean = false
    override fun isComplete(): Boolean = true
    override fun isSuccessful(): Boolean = false

    private val exception = Exception("Success was never an option")
}

object TelemetryLogging {
    @JvmStatic
    fun getClient(context: Context): TelemetryLoggingClient {
        return object : TelemetryLoggingClient {
            override fun log(data: TelemetryData): Task<Void?> {
                return DummyLogTask
            }
        }
    }

    @JvmStatic
    fun getClient(context: Context, options: TelemetryLoggingOptions): TelemetryLoggingClient {
        return getClient(context)
    }
}

interface TelemetryLoggingClient {
    fun log(data: TelemetryData): Task<Void?>
}

class TelemetryData(var1: Int, var2:List<MethodInvocation>?) {
    fun writeToParcel(var1: Parcel, var2: Int) {}
}

class MethodInvocation {

    constructor(methodKey:Int, resultStatusCode:Int, connectionResultStatusCode:Int,
                startTimeMillis:Long, endTimeMillis:Long,
                callingModuleId: String?, callingEntryPoint: String?, serviceId:Int)

    constructor(methodKey:Int, resultStatusCode:Int, connectionResultStatusCode:Int,
                startTimeMillis:Long, endTimeMillis:Long,
                callingModuleId: String?, callingEntryPoint: String?,
                serviceId:Int, var11:Int)

    fun writeToParcel(var1: Parcel, var2: Int) {}
}

it is possible to trim many transitive dependencies and save apk size:

implementation("com.google.mlkit:barcode-scanning:17.0.2") {
   exclude("com.google.android.gms", "play-services-base")
   exclude("com.google.android.datatransport", "transport-api")
   exclude("com.google.android.datatransport", "transport-backend-cct")
   exclude("com.google.android.datatransport", "transport-runtime")
   exclude("com.google.firebase", "firebase-encoders-json")
   exclude("com.google.firebase", "firebase-encoders")
}

However, as noted above, this is very fragile and will probably somehow break after MLKit update. It would be nice if this was not needed.