R8 consumer rules (#685)

* Ensuring demo app build fails due to R8 missing rules

* Fixing demo app serialization after obfuscation

* Adding code to check R8 rules around grpc exporters

core/consumer-rules.pro

@@ -0,0 +1,12 @@
+-dontwarn com.google.auto.value.AutoValue$Builder
+-dontwarn com.google.auto.value.AutoValue$CopyAnnotations
+-dontwarn com.google.auto.value.AutoValue
+-dontwarn com.google.auto.value.extension.memoized.Memoized
+-dontwarn io.grpc.Channel
+-dontwarn io.grpc.MethodDescriptor$Builder
+-dontwarn io.grpc.MethodDescriptor$Marshaller
+-dontwarn io.grpc.MethodDescriptor$MethodType
+-dontwarn io.grpc.MethodDescriptor
+-dontwarn io.grpc.stub.AbstractFutureStub
+-dontwarn io.grpc.stub.AbstractStub$StubFactory
+-dontwarn io.grpc.stub.AbstractStub

demo-app/build.gradle.kts

@@ -34,10 +34,7 @@ android {
         }
         release {
             isMinifyEnabled = true
-            proguardFiles(
-                getDefaultProguardFile("proguard-android-optimize.txt"),
-                "proguard-rules.pro",
-            )
+            signingConfig = signingConfigs["debug"]
         }
     }
     buildFeatures {

demo-app/src/main/java/io/opentelemetry/android/demo/OtelDemoApplication.kt

@@ -10,7 +10,6 @@ import android.app.Application
 import android.util.Log
 import io.opentelemetry.android.OpenTelemetryRum
 import io.opentelemetry.android.OpenTelemetryRumBuilder
-import io.opentelemetry.android.agent.setSlowRenderingDetectionPollInterval
 import io.opentelemetry.android.config.OtelRumConfig
 import io.opentelemetry.android.features.diskbuffering.DiskBufferingConfiguration
 import io.opentelemetry.api.common.AttributeKey.stringKey
@@ -19,9 +18,9 @@ import io.opentelemetry.api.incubator.events.EventBuilder
 import io.opentelemetry.api.trace.Tracer
 import io.opentelemetry.exporter.otlp.http.logs.OtlpHttpLogRecordExporter
 import io.opentelemetry.exporter.otlp.http.trace.OtlpHttpSpanExporter
+import io.opentelemetry.exporter.otlp.logs.OtlpGrpcLogRecordExporter
+import io.opentelemetry.exporter.otlp.trace.OtlpGrpcSpanExporter
 import io.opentelemetry.sdk.logs.internal.SdkEventLoggerProvider
-import java.time.Duration
-import kotlin.math.log
 
 const val TAG = "otel.demo"
 
@@ -62,6 +61,26 @@ class OtelDemoApplication : Application() {
         } catch (e: Exception) {
             Log.e(TAG, "Oh no!", e)
         }
+
+        // This is needed to get R8 missing rules warnings.
+        initializeOtelWithGrpc()
+    }
+
+    // This is not used but it's needed to verify that our consumer proguard rules cover this use case.
+    private fun initializeOtelWithGrpc() {
+        val builder = OpenTelemetryRum.builder(this)
+            .addSpanExporterCustomizer {
+                OtlpGrpcSpanExporter.builder().build()
+            }
+            .addLogRecordExporterCustomizer {
+                OtlpGrpcLogRecordExporter.builder().build()
+            }
+
+        // This is an overly-cautious measure to prevent R8 from discarding away the whole method
+        // in case it identifies that it's actually not doing anything meaningful.
+        if (System.currentTimeMillis() < 0) {
+            print(builder)
+        }
     }
 
     companion object {

demo-app/src/main/java/io/opentelemetry/android/demo/shop/model/Product.kt

@@ -1,22 +1,28 @@
 package io.opentelemetry.android.demo.shop.model
 
+import androidx.annotation.Keep
+
+@Keep
 data class Product(
     val id: String,
     val name: String,
     val description: String,
     val picture: String,
     val priceUsd: PriceUsd,
-    val categories: List<String>) {
+    val categories: List<String>
+) {
     fun priceValue(): Double {
-        return priceUsd.units.toDouble() + priceUsd.nanos.toDouble()/1_000_000_000f
+        return priceUsd.units.toDouble() + priceUsd.nanos.toDouble() / 1_000_000_000f
     }
 }
 
 // For deserialization
+@Keep
 data class ProductDeserializationWrapper(
     val products: List<Product>
 )
 
+@Keep
 data class PriceUsd(
     val currencyCode: String,
     val units: Long,