Added function to return pretty names on "system" module "process summary" metricset

CHANGELOG.asciidoc

@@ -127,6 +127,7 @@ https://github.com/elastic/beats/compare/v6.4.0...master[Check the HEAD diff]
 - Increase ignore_above for system.process.cmdline to 2048. {pull}8101[8100]
 - Add support to renamed fields planned for redis 5.0. {pull}8167[8167]
 - Allow TCP helper to support delimiters and graphite module to accept multiple metrics in a single payload. {pull}8278[8278]
+- Added 'died' PID state to process_system metricset on system module{pull}8275[8275]
 
 *Packetbeat*
 

metricbeat/docs/fields.asciidoc

@@ -19638,6 +19638,16 @@ type: long
 Number of zombie processes on this host.
 
 
+--
+
+*`system.process.summary.dead`*::
++
+--
+type: long
+
+Number of dead processes on this host. It's very unlikely that it will appear but in some special situations it may happen.
+
+
 --
 
 *`system.process.summary.unknown`*::

metricbeat/module/system/process_summary/_meta/fields.yml

@@ -29,6 +29,10 @@
       type: long
       description: >
         Number of zombie processes on this host.
+    - name: dead
+      type: long
+      description: >
+        Number of dead processes on this host. It's very unlikely that it will appear but in some special situations it may happen.
     - name: unknown
       type: long
       description: >

metricbeat/module/system/process_summary/process_summary.go

@@ -72,6 +72,7 @@ func (m *MetricSet) Fetch() (common.MapStr, error) {
 		stopped  int
 		zombie   int
 		unknown  int
+		dead     int
 	}
 
 	for _, pid := range pids {
@@ -95,8 +96,10 @@ func (m *MetricSet) Fetch() (common.MapStr, error) {
 			summary.stopped++
 		case 'Z':
 			summary.zombie++
+		case 'X':
+			summary.dead++
 		default:
-			logp.Err("Unknown state <%v> for process with pid %d", state.State, pid)
+			logp.Err("Unknown or unexpected state <%c> for process with pid %d", state.State, pid)
 			summary.unknown++
 		}
 	}
@@ -109,6 +112,7 @@ func (m *MetricSet) Fetch() (common.MapStr, error) {
 		"stopped":  summary.stopped,
 		"zombie":   summary.zombie,
 		"unknown":  summary.unknown,
+		"dead":     summary.dead,
 	}
 	// change the name space to use . instead of _
 	event[mb.NamespaceKey] = "process.summary"