the-algorithm/tweetypie/server/src/main/scala/com/twitter/tweetypie/store/TweetStatsStore.scala

package com.twitter.tweetypie
package store

import com.twitter.finagle.stats.RollupStatsReceiver
import com.twitter.servo.util.MemoizingStatsReceiver

/**
 * Records some stats about inserted tweets.  Tweets are currently classified by three criteria:
 *
 *     - tweet type: "tweet" or "retweet"
 *     - user type: "stresstest", "protected", "restricted", or "public"
 *     - fanout type: "nullcast", "narrowcast", or "usertimeline"
 *
 * A counter is incremented for a tweet using those three criteria in order.  Counters are
 * created with a RollupStatsReceiver, so counts are aggregated at each level.  Some
 * example counters are:
 *
 *    ./insert
 *    ./insert/tweet
 *    ./insert/tweet/public
 *    ./insert/tweet/protected/usertimeline
 *    ./insert/retweet/stresstest
 *    ./insert/retweet/public/nullcast
 */
trait TweetStatsStore extends TweetStoreBase[TweetStatsStore] with InsertTweet.Store {
  def wrap(w: TweetStore.Wrap): TweetStatsStore =
    new TweetStoreWrapper(w, this) with TweetStatsStore with InsertTweet.StoreWrapper
}

object TweetStatsStore {
  def apply(stats: StatsReceiver): TweetStatsStore = {
    val rollup = new MemoizingStatsReceiver(new RollupStatsReceiver(stats))
    val inserts = rollup.scope("insert")

    def tweetType(tweet: Tweet) =
      if (getShare(tweet).isDefined) "retweet" else "tweet"

    def userType(user: User) =
      if (user.roles.exists(_.roles.contains("stresstest"))) "stresstest"
      else if (user.safety.exists(_.isProtected)) "protected"
      else if (user.safety.exists(_.suspended)) "restricted"
      else "public"

    def fanoutType(tweet: Tweet) =
      if (TweetLenses.nullcast(tweet)) "nullcast"
      else if (TweetLenses.narrowcast(tweet).isDefined) "narrowcast"
      else "usertimeline"

    new TweetStatsStore {
      override val insertTweet: FutureEffect[InsertTweet.Event] =
        FutureEffect[InsertTweet.Event] { event =>
          inserts
            .counter(
              tweetType(event.tweet),
              userType(event.user),
              fanoutType(event.tweet)
            )
            .incr()

          Future.Unit
        }
    }
  }
}