Reaper should load initial state before listening to changes. There is a small window where if a device is removed or added during reaper startup it might go unnoticed, but it shouldn't be too much of a problem for us.

lib/units/reaper/index.js

@@ -56,18 +56,6 @@ module.exports = function(options) {
     lifecycle.fatal()
   })
 
-  sub.on('message', wirerouter()
-    .on(wire.DevicePresentMessage, function(channel, message) {
-      ttlset.bump(message.serial, Date.now())
-    })
-    .on(wire.DeviceHeartbeatMessage, function(channel, message) {
-      ttlset.bump(message.serial, Date.now())
-    })
-    .on(wire.DeviceAbsentMessage, function(channel, message) {
-      ttlset.drop(message.serial)
-    })
-    .handler())
-
   ttlset.on('timeout', function(serial) {
     log.info('Reaping device "%s" due to heartbeat timeout', serial)
     push.send([
@@ -78,20 +66,32 @@ module.exports = function(options) {
     ])
   })
 
-  dbapi.loadPresentDevices()
-    .then(function(cursor) {
-      return Promise.promisify(cursor.toArray, cursor)()
-        .then(function(list) {
-          var now = Date.now()
-          list.forEach(function(device) {
-            ttlset.bump(device.serial, now)
+  function loadInitialState() {
+    return dbapi.loadPresentDevices()
+      .then(function(cursor) {
+        return Promise.promisify(cursor.toArray, cursor)()
+          .then(function(list) {
+            var now = Date.now()
+            list.forEach(function(device) {
+              ttlset.bump(device.serial, now)
+            })
           })
-        })
-    })
-    .catch(function(err) {
-      log.error('Failed to load device list: ', err.stack)
-      lifecycle.fatal()
-    })
+      })
+  }
+
+  function listenToChanges() {
+    sub.on('message', wirerouter()
+      .on(wire.DevicePresentMessage, function(channel, message) {
+        ttlset.bump(message.serial, Date.now())
+      })
+      .on(wire.DeviceHeartbeatMessage, function(channel, message) {
+        ttlset.bump(message.serial, Date.now())
+      })
+      .on(wire.DeviceAbsentMessage, function(channel, message) {
+        ttlset.drop(message.serial)
+      })
+      .handler())
+  }
 
   log.info('Reaping devices with no heartbeat')
 
@@ -107,4 +107,6 @@ module.exports = function(options) {
 
     ttlset.stop()
   })
+
+  loadInitialState().then(listenToChanges)
 }