Don't rely on lucky timings when sending messages from the provider.

lib/roles/provider.js

@@ -9,12 +9,14 @@ var _ = require('lodash')
 var logger = require('../util/logger')
 var wire = require('../wire')
 var wireutil = require('../wire/util')
+var wirerouter = require('../wire/router')
 var procutil = require('../util/procutil')
 
 module.exports = function(options) {
   var log = logger.createLogger('provider')
   var client = Promise.promisifyAll(adb.createClient())
   var workers = {}
+  var solo = wireutil.makePrivateChannel()
   var lists = {
     all: []
   , ready: []
@@ -58,6 +60,19 @@ module.exports = function(options) {
     push.connect(endpoint)
   })
 
+  // Input
+  var sub = zmq.socket('sub')
+  options.endpoints.sub.forEach(function(endpoint) {
+    log.info('Receiving input from %s', endpoint)
+    sub.connect(endpoint)
+  })
+
+  // Establish always-on channels
+  ;[solo].forEach(function(channel) {
+    log.info('Subscribing to permanent channel "%s"', channel)
+    sub.subscribe(channel)
+  })
+
   // Track and manage devices
   client.trackDevicesAsync().then(function(tracker) {
     log.info('Tracking devices')
@@ -82,85 +97,119 @@ module.exports = function(options) {
     tracker.on('add', filterDevice(function(device) {
       log.info('Found device "%s" (%s)', device.id, device.type)
 
-      // Tell others we found a device
-      push.send([
-        wireutil.global
-      , wireutil.envelope(new wire.DevicePresentMessage(
-          device.id
-        , options.name
-        , wireutil.toDeviceStatus(device.type)
-        ))
-      ])
+      var privateTracker = new events.EventEmitter()
+        , timer
+        , worker
+
+      // Wait for others to acknowledge the device
+      var register = new Promise(function(resolve, reject) {
+        // Tell others we found a device
+        push.send([
+          wireutil.global
+        , wireutil.envelope(new wire.DevicePresentMessage(
+            device.id
+          , wireutil.toDeviceStatus(device.type)
+          , new wire.ProviderMessage(
+              solo
+            , options.name
+            )
+          ))
+        ])
+
+        privateTracker.once('register', resolve)
+      })
+
+      register.then(function() {
+        log.info('Registered device "%s"', device.id)
+        check()
+      })
 
       // Statistics
       lists.all.push(device.id)
       delayedTotals()
 
-      var privateTracker = new events.EventEmitter()
-        , resolver = Promise.defer()
-        , timer
-        , worker
+      // The device object will be kept up to date by the tracker, except
+      // our custom "present" property
+      _.assign(device, {
+        present: true
+      })
 
       // When any event occurs on the added device
-      function deviceListener(type, device) {
+      function deviceListener(type) {
         // Okay, this is a bit unnecessary but it allows us to get rid of an
         // ugly switch statement and return to the original style.
-        privateTracker.emit(type, device)
+        privateTracker.emit(type)
       }
 
       // When the added device changes
-      function changeListener(device) {
-        log.info('Device "%s" is now "%s"', device.id, device.type)
+      function changeListener() {
+        register.then(function() {
+          log.info('Device "%s" is now "%s"', device.id, device.type)
 
-        // Tell others the device changed
-        push.send([
-          wireutil.global
-        , wireutil.envelope(new wire.DeviceStatusMessage(
-            device.id
-          , wireutil.toDeviceStatus(device.type)
-          ))
-        ])
+          // Tell others the device changed
+          push.send([
+            wireutil.global
+          , wireutil.envelope(new wire.DeviceStatusMessage(
+              device.id
+            , wireutil.toDeviceStatus(device.type)
+            ))
+          ])
 
-        check(device)
+          check()
+        })
       }
 
       // When the added device gets removed
-      function removeListener(device) {
-        log.info('Lost device "%s" (%s)', device.id, device.type)
+      function removeListener() {
+        register.then(function() {
+          log.info('Lost device "%s" (%s)', device.id, device.type)
 
-        clearTimeout(timer)
-        flippedTracker.removeListener(device.id, deviceListener)
-        _.pull(lists.all, device.id)
-        delayedTotals()
+          clearTimeout(timer)
+          flippedTracker.removeListener(device.id, deviceListener)
+          _.pull(lists.all, device.id)
+          delayedTotals()
 
-        // Tell others the device is gone
-        push.send([
-          wireutil.global
-        , wireutil.envelope(new wire.DeviceAbsentMessage(
-            device.id
-          ))
-        ])
+          // Tell others the device is gone
+          push.send([
+            wireutil.global
+          , wireutil.envelope(new wire.DeviceAbsentMessage(
+              device.id
+            ))
+          ])
 
-        stop()
+          _.assign(device, {
+            present: false
+          })
+
+          check()
+        })
       }
 
       // Check if we can do anything with the device
-      function check(device) {
+      function check() {
         clearTimeout(timer)
-        switch (device.type) {
-          case 'device':
-          case 'emulator':
-            timer = setTimeout(work, 100)
-            break
-          default:
-            stop()
-            break
+
+        if (device.present) {
+          // We might get multiple status updates in rapid succession,
+          // so let's wait for a while
+          switch (device.type) {
+            case 'device':
+            case 'emulator':
+              timer = setTimeout(work, 100)
+              break
+            default:
+              timer = setTimeout(stop, 100)
+              break
+          }
+        }
+        else {
+          stop()
         }
       }
 
       // Starts a device worker and keeps it alive
       function work() {
-        return worker = workers[device.id] = spawn(device)
+        return worker = workers[device.id] = spawn()
           .then(function() {
             log.info('Device worker "%s" has retired', device.id)
             worker = workers[device.id] = null
@@ -188,7 +237,7 @@ module.exports = function(options) {
       }
 
       // Spawn a device worker
-      function spawn(device) {
+      function spawn() {
         var ports = options.ports.splice(0, 2)
           , proc = options.fork(device, ports)
           , resolver = Promise.defer()
@@ -272,7 +321,6 @@ module.exports = function(options) {
       flippedTracker.on(device.id, deviceListener)
       privateTracker.on('change', changeListener)
       privateTracker.on('remove', removeListener)
-      check(device)
     }))
 
     tracker.on('change', filterDevice(function(device) {
@@ -282,6 +330,12 @@ module.exports = function(options) {
     tracker.on('remove', filterDevice(function(device) {
       flippedTracker.emit(device.id, 'remove', device)
     }))
+
+    sub.on('message', wirerouter()
+      .on(wire.DeviceRegisteredMessage, function(channel, message) {
+        flippedTracker.emit(message.serial, 'register')
+      })
+      .handler())
   })
 
   function gracefullyExit() {