No functional channel provider found

[mamdouhweb]

While trying to run google-vision-api with a Scala project I'm getting the following exception.

io.grpc.ManagedChannelProvider$ProviderNotFoundException: No functional channel service provider found. Try adding a dependency on the grpc-okhttp or grpc-netty artifact
        at io.grpc.ManagedChannelProvider.provider(ManagedChannelProvider.java:126)
        at io.grpc.ManagedChannelBuilder.forAddress(ManagedChannelBuilder.java:45)
        at com.google.api.gax.grpc.InstantiatingChannelProvider.createChannel(InstantiatingChannelProvider.java:129)
        at com.google.api.gax.grpc.InstantiatingChannelProvider.getChannel(InstantiatingChannelProvider.java:116)
        at com.google.api.gax.grpc.ChannelAndExecutor.create(ChannelAndExecutor.java:65)
        at com.google.api.gax.grpc.ClientSettings.getChannelAndExecutor(ClientSettings.java:77)
        at com.google.cloud.vision.spi.v1.ImageAnnotatorClient.<init>(ImageAnnotatorClient.java:120)
        at com.google.cloud.vision.spi.v1.ImageAnnotatorClient.create(ImageAnnotatorClient.java:111)
        at com.google.cloud.vision.spi.v1.ImageAnnotatorClient.create(ImageAnnotatorClient.java:102)

I have tried changing the grpc-netty version and the http2 dependency from netty codec version as well. I also tried excluding the library and replacing it with grpc-okhttp to no hope!

Appreciate any help here

[vam-google]

Hi @mamdouhweb, please provide your project dependencies configuration (i.e. which artifacts and versions you depend on). Also, does it work if you try to do the same thing in java (i.e. is it specific to scala)?

[mamdouhweb]

@vam-google thanks for the quick reply. I haven't tried it in Java, I'm assuming it works as you guys have it in the examples.
as for my dependency list:

"joda-time" % "joda-time" % versions.jodaTime
"com.typesafe.akka" %% "akka-http-core" % versions.akkaHttpCore,
      "com.typesafe.akka" %% "akka-http" % versions.akkaHttp,
      "com.typesafe.akka" %% "akka-http-testkit" % versions.akkaHttpTestKit,
      "com.typesafe.akka" %% "akka-http-spray-json" % versions.akkaHttpSprayJson,
      "com.typesafe.akka" %% "akka-http-jackson" % versions.akkaHttpJackson,
      "com.typesafe.akka" %% "akka-slf4j" % versions.akkaSlf4j,
      "com.typesafe.scala-logging" %% "scala-logging-slf4j" % versions.slf4jScalaLogging,
      "org.slf4j" % "slf4j-api" % versions.slf4jAPI,
      "org.slf4j" % "log4j-over-slf4j" % versions.slf4jLog4j,
      "ch.qos.logback" % "logback-classic" % versions.logbackClassic,
      "ch.qos.logback" % "logback-core" % versions.logbackCore,
      "com.spotify" % "async-google-pubsub-client" % versions.cloudPubSub,
      "com.google.cloud" % "google-cloud-vision" % versions.cloudVision

I also ran dependency tree command and I can see grpc-netty, here's a screen shot that might be helpful

[mamdouhweb]

Addendum:
Cloud vision version is

val cloudVision = "0.18.0-beta"

Further, here's the code I'm using to test the library

import com.google.cloud.vision.spi.v1.{ImageAnnotatorClient, ImageAnnotatorSettings}
import com.google.cloud.vision.v1.Feature.Type
import com.google.cloud.vision.v1.{AnnotateImageRequest, Feature, Image, ImageSource}
import com.google.protobuf.Descriptors.FieldDescriptor
import com.spotify.google.cloud.pubsub.client.Message
import com.typesafe.scalalogging.slf4j.LazyLogging
import org.threeten.bp.Duration

import scala.collection.JavaConversions._
import scala.collection.mutable

def detectImageLabels(
      fileName: String): mutable.Buffer[Seq[mutable.Map[FieldDescriptor, String]]] = {

    val imageAnnotatorSettingsBuilder =
      ImageAnnotatorSettings.defaultBuilder()

    imageAnnotatorSettingsBuilder
      .batchAnnotateImagesSettings()
      .getRetrySettingsBuilder
      .setTotalTimeout(Duration.ofSeconds(30))

    val settings = imageAnnotatorSettingsBuilder.build()

    val vision = ImageAnnotatorClient.create(settings)

    val gcsPath = "gs://" + bucketName + "/" + fileName

    val imageSource = ImageSource.newBuilder().setGcsImageUri(gcsPath).build()

    val image = Image.newBuilder().setSource(imageSource).build()

    val feature = Feature.newBuilder().setType(Type.LABEL_DETECTION).build()

    val request =
      AnnotateImageRequest.newBuilder().addFeatures(feature).setImage(image).build()

    val requests: List[AnnotateImageRequest] = List(request)

    val response = vision.batchAnnotateImages(requests)

    val responses = response.getResponsesList

    responses.map { response =>
      if (!response.hasError) {
        response.getLabelAnnotationsList.map { annotation =>
          annotation.getAllFields.map { field =>
            logger.info("label detected: " + field._1.getFullName + " " + field._2.toString)
            (field._1, field._2.toString)
          }
        }
      } else {
        logger.error("error detecting labels for Image: " + fileName)
        List()
      }
    }
  }

[mamdouhweb]

After a fight with this issue, it is fixed now!

The main cause of the issue is the horrifying combination between io.netty.versions.properties and sbt assembly

That said, this is definitely not a bug, and I apologize for taking your time @vam-google
For anyone in the future who might face the same problem, just add the following line in your projectAssemblySettings

case PathList("META-INF", "io.netty.versions.properties") => MergeStrategy.rename 

// Note: using any of the following MergeStrategies (last, first or discard) will definitely cause issues, I haven't tried merge but you can definitely try it yourself :)

[vam-google]

Good to hear that it is not a bug =). Closing the issue.