Report DEAD (X) State Process (influxdata#2501)

Report count of processes in dead (X) process state from the processes input.  This process state is only valid on Linux.

CHANGELOG.md

@@ -57,6 +57,7 @@ be deprecated eventually.
 - [#2387](https://github.com/influxdata/telegraf/pull/2387): Added histogram aggregator plugin.
 - [#2071](https://github.com/influxdata/telegraf/issues/2071): Use official docker SDK.
 - [#1678](https://github.com/influxdata/telegraf/pull/1678): Add AMQP consumer input plugin
+- [#2501](https://github.com/influxdata/telegraf/pull/2501): Support DEAD(X) state in system input plugin.
 
 ### Bugfixes
 

plugins/inputs/system/PROCESSES_README.md

@@ -23,6 +23,7 @@ it requires access to execute `ps`.
     - stopped
     - total
     - zombie
+    - dead
     - wait (freebsd only)
     - idle (bsd only)
     - paging (linux only)
@@ -39,6 +40,7 @@ Linux  FreeBSD  Darwin  meaning
   R       R       R     running
   S       S       S     sleeping
   Z       Z       Z     zombie
+  X      none    none   dead
   T       T       T     stopped
  none     I       I     idle (sleeping for longer than about 20 seconds)
   D      D,L      U     blocked (waiting in uninterruptible sleep, or locked)
@@ -54,5 +56,5 @@ None
 ```
 $ telegraf -config ~/ws/telegraf.conf -input-filter processes -test
 * Plugin: processes, Collection 1
-> processes blocked=8i,running=1i,sleeping=265i,stopped=0i,total=274i,zombie=0i,paging=0i,total_threads=687i 1457478636980905042
+> processes blocked=8i,running=1i,sleeping=265i,stopped=0i,total=274i,zombie=0i,dead=0i,paging=0i,total_threads=687i 1457478636980905042
 ```

plugins/inputs/system/processes.go

@@ -81,6 +81,7 @@ func getEmptyFields() map[string]interface{} {
 	case "openbsd":
 		fields["idle"] = int64(0)
 	case "linux":
+		fields["dead"] = int64(0)
 		fields["paging"] = int64(0)
 		fields["total_threads"] = int64(0)
 	}
@@ -107,6 +108,8 @@ func (p *Processes) gatherFromPS(fields map[string]interface{}) error {
 			fields["blocked"] = fields["blocked"].(int64) + int64(1)
 		case 'Z':
 			fields["zombies"] = fields["zombies"].(int64) + int64(1)
+		case 'X':
+			fields["dead"] = fields["dead"].(int64) + int64(1)
 		case 'T':
 			fields["stopped"] = fields["stopped"].(int64) + int64(1)
 		case 'R':
@@ -164,6 +167,8 @@ func (p *Processes) gatherFromProc(fields map[string]interface{}) error {
 			fields["blocked"] = fields["blocked"].(int64) + int64(1)
 		case 'Z':
 			fields["zombies"] = fields["zombies"].(int64) + int64(1)
+		case 'X':
+			fields["dead"] = fields["dead"].(int64) + int64(1)
 		case 'T', 't':
 			fields["stopped"] = fields["stopped"].(int64) + int64(1)
 		case 'W':