An example of the apollo tracing GraphQL extension with Sangria

ApolloTracingExtension.scala

import java.time.Instant
import java.time.format.DateTimeFormatter
import java.util.concurrent.ConcurrentLinkedQueue

import sangria.ast._
import sangria.execution._
import sangria.schema.Context
import sangria.marshalling.queryAst._
import sangria.renderer.SchemaRenderer

import scala.collection.JavaConverters._

object ApolloTracingExtension extends Middleware[Any] with MiddlewareExtension[Any] with MiddlewareAfterField[Any] with MiddlewareErrorField[Any] {
  type QueryVal = QueryTrace
  type FieldVal = Long

  def beforeQuery(context: MiddlewareQueryContext[Any, _, _]) =
    QueryTrace(Instant.now(), System.nanoTime(), new ConcurrentLinkedQueue)

  def afterQuery(queryVal: QueryVal, context: MiddlewareQueryContext[Any, _, _]) = ()

  def beforeField(queryVal: QueryVal, mctx: MiddlewareQueryContext[Any, _, _], ctx: Context[Any, _]) =
    continue(System.nanoTime())

  def afterField(queryVal: QueryVal, fieldVal: FieldVal, value: Any, mctx: MiddlewareQueryContext[Any, _, _], ctx: Context[Any, _]) = {
    updateMetric(queryVal, fieldVal, ctx)
    None
  }

  def fieldError(queryVal: QueryVal, fieldVal: FieldVal, error: Throwable, mctx: MiddlewareQueryContext[Any, _, _], ctx: Context[Any, _]) =
    updateMetric(queryVal, fieldVal, ctx)

  def updateMetric(queryVal: QueryVal, fieldVal: FieldVal, ctx: Context[Any, _]): Unit =
    queryVal.fieldData.add(ObjectValue(
      "path" → ListValue(ctx.path.path.map(queryAstResultMarshaller.scalarNode(_, "Any", Set.empty))),
      "fieldName" → StringValue(ctx.field.name),
      "parentType" → StringValue(ctx.parentType.name),
      "returnType" → StringValue(SchemaRenderer.renderTypeName(ctx.field.fieldType)),
      "startOffset" → BigIntValue(fieldVal - queryVal.startNanos),
      "duration" → BigIntValue(System.nanoTime() - fieldVal)))

  def afterQueryExtensions(queryVal: QueryVal, context: MiddlewareQueryContext[Any, _, _]): Vector[Extension[_]] =
    Vector(Extension(ObjectValue(
      "tracing" → ObjectValue(
        "version" → IntValue(1),
        "startTime" → StringValue(DateTimeFormatter.ISO_INSTANT.format(queryVal.startTime)),
        "endTime" → StringValue(DateTimeFormatter.ISO_INSTANT.format(Instant.now())),
        "duration" → BigIntValue(System.nanoTime() - queryVal.startNanos),
        "execution" → ObjectValue(
          "resolvers" → ListValue(queryVal.fieldData.asScala.toVector)))): Value))

  case class QueryTrace(startTime: Instant, startNanos: Long, fieldData: ConcurrentLinkedQueue[Value])
}

UsageExample.scala

Executor.execute(schema, query, middleware = ApolloTracingExtension :: Nil)

z-example-query.graphql

{
  human(id: "1000") {
    name
    
    friends {
      name
    }
  }
}

z-example-result.json

{
  "data": {
    "human": {
      "name": "Luke Skywalker",
      "friends": [
        {
          "name": "Han Solo"
        },
        {
          "name": "Leia Organa"
        },
        {
          "name": "C-3PO"
        },
        {
          "name": "R2-D2"
        }
      ]
    }
  },
  "extensions": {
    "tracing": {
      "version": 1,
      "startTime": "2017-07-31T14:32:42.844Z",
      "endTime": "2017-07-31T14:32:43.100Z",
      "duration": 255216221,
      "execution": {
        "resolvers": [
          {
            "path": [
              "human"
            ],
            "fieldName": "human",
            "parentType": "Query",
            "returnType": "Human",
            "startOffset": 311002,
            "duration": 1968408
          },
          {
            "path": [
              "human",
              "name"
            ],
            "fieldName": "name",
            "parentType": "Human",
            "returnType": "String",
            "startOffset": 2388537,
            "duration": 151844
          },
          {
            "path": [
              "human",
              "friends"
            ],
            "fieldName": "friends",
            "parentType": "Human",
            "returnType": "[Character!]!",
            "startOffset": 2657994,
            "duration": 249770918
          },
          {
            "path": [
              "human",
              "friends",
              0,
              "name"
            ],
            "fieldName": "name",
            "parentType": "Human",
            "returnType": "String",
            "startOffset": 253261565,
            "duration": 21650
          },
          {
            "path": [
              "human",
              "friends",
              1,
              "name"
            ],
            "fieldName": "name",
            "parentType": "Human",
            "returnType": "String",
            "startOffset": 253377422,
            "duration": 9363
          },
          {
            "path": [
              "human",
              "friends",
              2,
              "name"
            ],
            "fieldName": "name",
            "parentType": "Droid",
            "returnType": "String",
            "startOffset": 253456124,
            "duration": 545641
          },
          {
            "path": [
              "human",
              "friends",
              3,
              "name"
            ],
            "fieldName": "name",
            "parentType": "Droid",
            "returnType": "String",
            "startOffset": 253599190,
            "duration": 420130
          }
        ]
      }
    }
  }
}