No implicits found for parameter sprayJsonReader: JsonReader[T]

Question

I have created an sbt project to learn how to use elastic search with akka. I came across alpakka which provides this feature (to connect with elasticsearch). According to docs, to search from ES we have following code:

val connectionSettings = ElasticsearchConnectionSettings("http://localhost:9200")
  val sourceSettings = ElasticsearchSourceSettings(connectionSettings)
  val elasticsearchParamsV7 = ElasticsearchParams.V7("index")
  val copy = ElasticsearchSource
    .typed[User](
      elasticsearchParamsV7,
      query = """{"match_all": {}}""",
      sourceSettings
    )

    import spray.json.{DefaultJsonProtocol, RootJsonFormat}
case class User(first_name: String, last_name: String, email: String)

object MyJsonProtocol extends DefaultJsonProtocol {
  implicit val userFormat: RootJsonFormat[User] = jsonFormat3(User)
}

What I found that an error showing related to spray json reader saying...

No implicits found for parameter sprayJsonReader: JsonReader[User]

I do not know what I am missing here.

I have already imported two libraries

"akka-http-spray-json"
"spray-json"

in build.sbt file

Answer 1

Your userFormat isn't in scope for ElasticsearchSource.typed, so import it, e.g.:

import MyJsonProtocol.userFormat

val copy = ElasticsearchSource.typed[User](
  elasticsearchParamsV7,
  query = """{ "match_all": {} }""",
  sourceSettings
)