Don't allow minicap to fail more than 3 times in 10s.

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

@@ -16,6 +16,7 @@ var FrameConfig = require('./util/frameconfig')
 var BroadcastSet = require('./util/broadcastset')
 var StateQueue = require('./util/statequeue')
 var RiskyStream = require('./util/riskystream')
+var FailCounter = require('./util/failcounter')
 
 module.exports = syrup.serial()
   .dependency(require('../../support/adb'))
@@ -38,6 +39,9 @@ module.exports = syrup.serial()
       this.readable = false
       this.needsReadable = false
       this.starter = Promise.resolve(true)
+      this.failCounter = new FailCounter(3, 10000)
+      this.failCounter.on('exceedLimit', this._failLimitExceeded.bind(this))
+      this.failed = false
     }
 
     util.inherits(FrameProducer, EventEmitter)
@@ -52,6 +56,11 @@ module.exports = syrup.serial()
         return
       }
 
+      if (this.failed) {
+        log.warn('Will not apply desired state due to too many failures')
+        return
+      }
+
       switch (this.runningState) {
       case FrameProducer.STATE_STARTING:
       case FrameProducer.STATE_STOPPING:
@@ -88,6 +97,7 @@ module.exports = syrup.serial()
             })
             .catch(function(err) {
               return this._stop().finally(function() {
+                this.failCounter.inc()
                 this.emit('error', err)
               })
             })
@@ -191,14 +201,26 @@ module.exports = syrup.serial()
 
     FrameProducer.prototype._socketEnded = function() {
       log.warn('Connection to minicap ended unexpectedly')
+      this.failCounter.inc()
       this.restart()
     }
 
     FrameProducer.prototype._outputEnded = function() {
       log.warn('Shell keeping minicap running ended unexpectedly')
+      this.failCounter.inc()
       this.restart()
     }
 
+    FrameProducer.prototype._failLimitExceeded = function(limit, time) {
+      this._stop()
+      this.failed = true
+      this.emit('error', new Error(util.format(
+        'Failed more than %d times in %dms'
+      , limit
+      , time
+      )))
+    }
+
     FrameProducer.prototype._startService = function() {
       log.info('Launching screen service')
       return minicap.run(util.format('-S -P %s', this.frameConfig.toString()))

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

@@ -0,0 +1,32 @@
+var util = require('util')
+
+var EventEmitter = require('eventemitter3').EventEmitter
+
+function FailCounter(threshold, time) {
+  this.threshold = threshold
+  this.time = time
+  this.values = []
+}
+
+util.inherits(FailCounter, EventEmitter)
+
+FailCounter.prototype.inc = function() {
+  var now = Date.now()
+
+  while (this.values.length) {
+    if (now - this.values[0] >= this.time) {
+      this.values.shift()
+    }
+    else {
+      break
+    }
+  }
+
+  this.values.push(now)
+
+  if (this.values.length > this.threshold) {
+    this.emit('exceedLimit', this.threshold, this.time)
+  }
+}
+
+module.exports = FailCounter