com.twitter.server.handler.MetricQueryHandler.scala Maven / Gradle / Ivy

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package com.twitter.server.handler

import com.twitter.finagle.Service
import com.twitter.finagle.http.{Request, Response}
import com.twitter.io.Buf
import com.twitter.server.util.HttpUtils.{newResponse, parse}
import com.twitter.server.util.{JsonConverter, MetricSource}
import com.twitter.util.Future

private object MetricQueryHandler {
  def render(title: String, keys: Set[String]): String =
    s"""
        
        
        
          
            
              ${ (for (key <- keys.toSeq.sorted) yield {
                    s"""$key"""
                  }).mkString("\n") }
            
          
          
            
          
        """
}

/**
 * A handler which accepts metrics queries via http query strings and returns
 * json encoded metrics.
 */
class MetricQueryHandler(source: MetricSource = new MetricSource)
  extends Service[Request, Response] {
  import MetricQueryHandler._

  private[this] def query(keys: Seq[String]) =
    for (k <- keys; e <- source.get(k)) yield e

  def apply(req: Request): Future[Response] = {
    val (_, params) = parse(req.uri)

    params.getOrElse("m", Nil) match {
      case Nil =>
        newResponse(
          contentType = "text/html;charset=UTF-8",
          content = Buf.Utf8(render("Test", source.keySet))
        )

      case someKeys =>
        newResponse(
          contentType = "application/json;charset=UTF-8",
          content = Buf.Utf8(JsonConverter.writeToString(query(someKeys)))
        )
    }
  }
}