Enable plugins to emit stat into L5D stat trees for Announcer

Issue Type:

• Bug report
• [ X] Feature request

We are writing multiple plugins for our L5D mesh, there are needs to initialize a finagle client to perform RPC, however there is no way to submit the stat into L5D metrics system.

Suggestion: Is it possible to enable this user scenario?

def getClient(withRequestTimeoutMS: Int =  1000 , addr: InetSocketAddress, path:Path): Service[http.Request, http.Response]  = {
    val monitor: Monitor = new Monitor {
      def handle(t: Throwable): Boolean = {
        logger.error(t, t.getMessage, t.getStackTrace)
        true
      }
    }
    val metrics = MetricsTree() // possible to get the metrics tree from global 
    val stats = new MetricsTreeStatsReceiver(metrics) // register this stat object to be collected?
    Http.client
      .withStatsReceiver(stats)
      .withHttpStats
      .withRequestTimeout(Duration.fromMilliseconds(withRequestTimeoutMS))
      .withMonitor(monitor)
      .newService(s"${addr.getHostName()}:${addr.getPort()}", "hc_client")

  }

[koiuo]

If the intention is to see stats under admin/metrics.json, then it is already possible with linkerd.

Usually (I’d say, always, but maybe some type of plugins miss that still) plugin factory method receives Stack.Params as an argument, and one can obtain StatsReceiver from it:

val stats = params[param.Stats].statsReceiver

[leozc]

Resolved!