add preprocessor for RST docs, see #2461 and #2431

The idea is to filter the sources, replacing @<var>@ occurrences with
the mapping for <var> (which is currently hard-coded). @@ -> @. In order
to make this work, I had to move the doc sources one directory down
(into akka-docs/rst) so that the filtered result could be in a sibling
directory so that relative links (to _sphinx plugins or real code) would
continue to work.

While I was at it I also changed it so that WARNINGs and ERRORs are not
swallowed into the debug dump anymore but printed at [warn] level
(minimum).

One piece of fallout is that the (online) html build is now run after
the normal one, not in parallel.

akka-docs/rst/scala/code/docs/zeromq/ZeromqDocSpec.scala

@@ -0,0 +1,184 @@
+/**
+ * Copyright (C) 2009-2012 Typesafe Inc. <http://www.typesafe.com>
+ */
+package docs.zeromq
+
+import language.postfixOps
+
+import akka.actor.{ Actor, Props }
+import scala.concurrent.util.duration._
+import akka.testkit._
+import akka.zeromq.{ ZeroMQVersion, ZeroMQExtension }
+import java.text.SimpleDateFormat
+import java.util.Date
+import akka.zeromq.{ SocketType, Bind }
+
+object ZeromqDocSpec {
+
+  //#health
+  import akka.zeromq._
+  import akka.actor.Actor
+  import akka.actor.Props
+  import akka.actor.ActorLogging
+  import akka.serialization.SerializationExtension
+  import java.lang.management.ManagementFactory
+
+  case object Tick
+  case class Heap(timestamp: Long, used: Long, max: Long)
+  case class Load(timestamp: Long, loadAverage: Double)
+
+  class HealthProbe extends Actor {
+
+    val pubSocket = ZeroMQExtension(context.system).newSocket(SocketType.Pub, Bind("tcp://127.0.0.1:1235"))
+    val memory = ManagementFactory.getMemoryMXBean
+    val os = ManagementFactory.getOperatingSystemMXBean
+    val ser = SerializationExtension(context.system)
+    import context.dispatcher
+
+    override def preStart() {
+      context.system.scheduler.schedule(1 second, 1 second, self, Tick)
+    }
+
+    override def postRestart(reason: Throwable) {
+      // don't call preStart, only schedule once
+    }
+
+    def receive: Receive = {
+      case Tick ⇒
+        val currentHeap = memory.getHeapMemoryUsage
+        val timestamp = System.currentTimeMillis
+
+        // use akka SerializationExtension to convert to bytes
+        val heapPayload = ser.serialize(Heap(timestamp, currentHeap.getUsed, currentHeap.getMax)).get
+        // the first frame is the topic, second is the message
+        pubSocket ! ZMQMessage(Seq(Frame("health.heap"), Frame(heapPayload)))
+
+        // use akka SerializationExtension to convert to bytes
+        val loadPayload = ser.serialize(Load(timestamp, os.getSystemLoadAverage)).get
+        // the first frame is the topic, second is the message
+        pubSocket ! ZMQMessage(Seq(Frame("health.load"), Frame(loadPayload)))
+    }
+  }
+  //#health
+
+  //#logger
+  class Logger extends Actor with ActorLogging {
+
+    ZeroMQExtension(context.system).newSocket(SocketType.Sub, Listener(self), Connect("tcp://127.0.0.1:1235"), Subscribe("health"))
+    val ser = SerializationExtension(context.system)
+    val timestampFormat = new SimpleDateFormat("HH:mm:ss.SSS")
+
+    def receive = {
+      // the first frame is the topic, second is the message
+      case m: ZMQMessage if m.firstFrameAsString == "health.heap" ⇒
+        val Heap(timestamp, used, max) = ser.deserialize(m.payload(1), classOf[Heap]).get
+        log.info("Used heap {} bytes, at {}", used, timestampFormat.format(new Date(timestamp)))
+
+      case m: ZMQMessage if m.firstFrameAsString == "health.load" ⇒
+        val Load(timestamp, loadAverage) = ser.deserialize(m.payload(1), classOf[Load]).get
+        log.info("Load average {}, at {}", loadAverage, timestampFormat.format(new Date(timestamp)))
+    }
+  }
+  //#logger
+
+  //#alerter
+  class HeapAlerter extends Actor with ActorLogging {
+
+    ZeroMQExtension(context.system).newSocket(SocketType.Sub, Listener(self), Connect("tcp://127.0.0.1:1235"), Subscribe("health.heap"))
+    val ser = SerializationExtension(context.system)
+    var count = 0
+
+    def receive = {
+      // the first frame is the topic, second is the message
+      case m: ZMQMessage if m.firstFrameAsString == "health.heap" ⇒
+        val Heap(timestamp, used, max) = ser.deserialize(m.payload(1), classOf[Heap]).get
+        if ((used.toDouble / max) > 0.9) count += 1
+        else count = 0
+        if (count > 10) log.warning("Need more memory, using {} %", (100.0 * used / max))
+    }
+  }
+  //#alerter
+
+}
+
+class ZeromqDocSpec extends AkkaSpec("akka.loglevel=INFO") {
+  import ZeromqDocSpec._
+
+  "demonstrate how to create socket" in {
+    checkZeroMQInstallation()
+
+    //#pub-socket
+    import akka.zeromq.ZeroMQExtension
+    val pubSocket = ZeroMQExtension(system).newSocket(SocketType.Pub, Bind("tcp://127.0.0.1:21231"))
+    //#pub-socket
+
+    //#sub-socket
+    import akka.zeromq._
+    val listener = system.actorOf(Props(new Actor {
+      def receive: Receive = {
+        case Connecting    ⇒ //...
+        case m: ZMQMessage ⇒ //...
+        case _             ⇒ //...
+      }
+    }))
+    val subSocket = ZeroMQExtension(system).newSocket(SocketType.Sub, Listener(listener), Connect("tcp://127.0.0.1:21231"), SubscribeAll)
+    //#sub-socket
+
+    //#sub-topic-socket
+    val subTopicSocket = ZeroMQExtension(system).newSocket(SocketType.Sub, Listener(listener), Connect("tcp://127.0.0.1:21231"), Subscribe("foo.bar"))
+    //#sub-topic-socket
+
+    //#unsub-topic-socket
+    subTopicSocket ! Unsubscribe("foo.bar")
+    //#unsub-topic-socket
+
+    val payload = Array.empty[Byte]
+    //#pub-topic
+    pubSocket ! ZMQMessage(Seq(Frame("foo.bar"), Frame(payload)))
+    //#pub-topic
+
+    system.stop(subSocket)
+    system.stop(subTopicSocket)
+
+    //#high-watermark
+    val highWatermarkSocket = ZeroMQExtension(system).newSocket(
+      SocketType.Router,
+      Listener(listener),
+      Bind("tcp://127.0.0.1:21233"),
+      HighWatermark(50000))
+    //#high-watermark
+  }
+
+  "demonstrate pub-sub" in {
+    checkZeroMQInstallation()
+
+    //#health
+
+    system.actorOf(Props[HealthProbe], name = "health")
+    //#health
+
+    //#logger
+
+    system.actorOf(Props[Logger], name = "logger")
+    //#logger
+
+    //#alerter
+
+    system.actorOf(Props[HeapAlerter], name = "alerter")
+    //#alerter
+
+    // Let it run for a while to see some output.
+    // Don't do like this in real tests, this is only doc demonstration.
+    Thread.sleep(3.seconds.toMillis)
+
+  }
+
+  def checkZeroMQInstallation() = try {
+    ZeroMQExtension(system).version match {
+      case ZeroMQVersion(2, 1, _) ⇒ Unit
+      case version                ⇒ pending
+    }
+  } catch {
+    case e: LinkageError ⇒ pending
+  }
+}