Fix unexpected minicap death during start causing a TimeoutError, causing the licecycle to end unnecessarily. Now it will just try again like it should have from the start.

lib/units/device/plugins/screen/stream.js

@@ -37,6 +37,7 @@ module.exports = syrup.serial()
       this.frameConfig = config
       this.readable = false
       this.needsReadable = false
+      this.starter = Promise.resolve(true)
     }
 
     util.inherits(FrameProducer, EventEmitter)
@@ -47,6 +48,10 @@ module.exports = syrup.serial()
     FrameProducer.STATE_STOPPING = 4
 
     FrameProducer.prototype._ensureState = function() {
+      if (this.desiredState.empty()) {
+        return
+      }
+
       switch (this.runningState) {
       case FrameProducer.STATE_STARTING:
       case FrameProducer.STATE_STOPPING:
@@ -55,7 +60,7 @@ module.exports = syrup.serial()
       case FrameProducer.STATE_STOPPED:
         if (this.desiredState.next() === FrameProducer.STATE_STARTED) {
           this.runningState = FrameProducer.STATE_STARTING
-          this._startService().bind(this)
+          this.starter = this._startService().bind(this)
             .then(function(out) {
               this.output = new RiskyStream(out)
                 .on('unexpectedEnd', this._outputEnded.bind(this))
@@ -78,42 +83,31 @@ module.exports = syrup.serial()
               this.runningState = FrameProducer.STATE_STARTED
               this.emit('start')
             })
+            .catch(Promise.CancellationError, function() {
+              return this._stop()
+            })
             .catch(function(err) {
-              this.runningState = FrameProducer.STATE_STOPPED
-              this.emit('error', err)
+              return this._stop().finally(function() {
+                this.emit('error', err)
+              })
             })
             .finally(function() {
               this._ensureState()
             })
         }
+        else {
+          setImmediate(this._ensureState.bind(this))
+        }
         break
       case FrameProducer.STATE_STARTED:
         if (this.desiredState.next() === FrameProducer.STATE_STOPPED) {
           this.runningState = FrameProducer.STATE_STOPPING
-          this._disconnectService(this.socket).bind(this)
-            .timeout(2000)
-            .then(function() {
-              return this._stopService(this.output).timeout(10000)
-            })
-            .then(function() {
-              this.runningState = FrameProducer.STATE_STOPPED
-              this.emit('stop')
-            })
-            .catch(function(err) {
-              // In practice we _should_ never get here due to _stopService()
-              // being quite aggressive. But if we do, well... assume it
-              // stopped anyway for now.
-              this.runningState = FrameProducer.STATE_STOPPED
-              this.emit('error', err)
-              this.emit('stop')
-            })
-            .finally(function() {
-              this.output = null
-              this.socket = null
-              this.banner = null
-              this.parser = null
-              this._ensureState()
-            })
+          this._stop().finally(function() {
+            this._ensureState()
+          })
+        }
+        else {
+          setImmediate(this._ensureState.bind(this))
         }
         break
       }
@@ -135,6 +129,7 @@ module.exports = syrup.serial()
       switch (this.runningState) {
       case FrameProducer.STATE_STARTED:
       case FrameProducer.STATE_STARTING:
+        this.starter.cancel()
         this.desiredState.push(FrameProducer.STATE_STOPPED)
         this.desiredState.push(FrameProducer.STATE_STARTED)
         this._ensureState()
@@ -248,6 +243,32 @@ module.exports = syrup.serial()
       return tryConnect(5, 100)
     }
 
+    FrameProducer.prototype._stop = function() {
+      return this._disconnectService(this.socket).bind(this)
+        .timeout(2000)
+        .then(function() {
+          return this._stopService(this.output).timeout(10000)
+        })
+        .then(function() {
+          this.runningState = FrameProducer.STATE_STOPPED
+          this.emit('stop')
+        })
+        .catch(function(err) {
+          // In practice we _should_ never get here due to _stopService()
+          // being quite aggressive. But if we do, well... assume it
+          // stopped anyway for now.
+          this.runningState = FrameProducer.STATE_STOPPED
+          this.emit('error', err)
+          this.emit('stop')
+        })
+        .finally(function() {
+          this.output = null
+          this.socket = null
+          this.banner = null
+          this.parser = null
+        })
+    }
+
     FrameProducer.prototype._disconnectService = function(socket) {
       log.info('Disconnecting from minicap service')
 

lib/units/device/plugins/screen/util/statequeue.js

@@ -6,6 +6,10 @@ StateQueue.prototype.next = function() {
   return this.queue.shift()
 }
 
+StateQueue.prototype.empty = function() {
+  return this.queue.length === 0
+}
+
 StateQueue.prototype.push = function(state) {
   var found = false