Add PPID field to procstat input plugin (#8887)

plugins/inputs/procstat/process.go

@@ -26,6 +26,7 @@ type Process interface {
 	RlimitUsage(bool) ([]process.RlimitStat, error)
 	Username() (string, error)
 	CreateTime() (int64, error)
+	Ppid() (int32, error)
 }
 
 type PIDFinder interface {

plugins/inputs/procstat/procstat.go

@@ -311,6 +311,11 @@ func (p *Procstat) addMetric(proc Process, acc telegraf.Accumulator, t time.Time
 		}
 	}
 
+	ppid, err := proc.Ppid()
+	if err == nil {
+		fields[prefix+"ppid"] = ppid
+	}
+
 	acc.AddFields("procstat", fields, proc.Tags(), t)
 }
 

plugins/inputs/procstat/procstat_test.go

@@ -164,6 +164,10 @@ func (p *testProc) RlimitUsage(_ bool) ([]process.RlimitStat, error) {
 	return []process.RlimitStat{}, nil
 }
 
+func (p *testProc) Ppid() (int32, error) {
+	return 0, nil
+}
+
 var pid = PID(42)
 var exe = "foo"