Add cmdline tag to procstat input (influxdata#5681)

Author: scottprichard

plugins/inputs/procstat/README.md

@@ -41,6 +41,9 @@ Processes can be selected for monitoring using one of several methods:
   ## Field name prefix
   # prefix = ""
 
+  ## When true add the full cmdline as a tag.
+  # cmdline_tag = false
+
   ## Add PID as a tag instead of a field; useful to differentiate between
   ## processes whose tags are otherwise the same.  Can create a large number
   ## of series, use judiciously.
@@ -72,6 +75,7 @@ implemented as a WMI query.  The pattern allows fuzzy matching using only
 - procstat
   - tags:
     - pid (when `pid_tag` is true)
+    - cmdline (when 'cmdline_tag' is true)
     - process_name
     - pidfile (when defined)
     - exe (when defined)

plugins/inputs/procstat/process.go

@@ -15,6 +15,7 @@ type Process interface {
 	IOCounters() (*process.IOCountersStat, error)
 	MemoryInfo() (*process.MemoryInfoStat, error)
 	Name() (string, error)
+	Cmdline() (string, error)
 	NumCtxSwitches() (*process.NumCtxSwitchesStat, error)
 	NumFDs() (int32, error)
 	NumThreads() (int32, error)

plugins/inputs/procstat/procstat.go

@@ -27,6 +27,7 @@ type Procstat struct {
 	Exe         string
 	Pattern     string
 	Prefix      string
+	CmdLineTag  bool `toml:"cmdline_tag"`
 	ProcessName string
 	User        string
 	SystemdUnit string
@@ -65,6 +66,9 @@ var sampleConfig = `
   ## Field name prefix
   # prefix = ""
 
+  ## When true add the full cmdline as a tag.
+  # cmdline_tag = false
+
   ## Add PID as a tag instead of a field; useful to differentiate between
   ## processes whose tags are otherwise the same.  Can create a large number
   ## of series, use judiciously.
@@ -170,6 +174,16 @@ func (p *Procstat) addMetric(proc Process, acc telegraf.Accumulator) {
 		fields["pid"] = int32(proc.PID())
 	}
 
+	//If cmd_line tag is true and it is not already set add cmdline as a tag
+	if p.CmdLineTag {
+		if _, ok := proc.Tags()["cmdline"]; !ok {
+			Cmdline, err := proc.Cmdline()
+			if err == nil {
+				proc.Tags()["cmdline"] = Cmdline
+			}
+		}
+	}
+
 	numThreads, err := proc.NumThreads()
 	if err == nil {
 		fields[prefix+"num_threads"] = numThreads

plugins/inputs/procstat/procstat_test.go

@@ -76,6 +76,10 @@ func (pg *testPgrep) PidFile(path string) ([]PID, error) {
 	return pg.pids, pg.err
 }
 
+func (p *testProc) Cmdline() (string, error) {
+	return "test_proc", nil
+}
+
 func (pg *testPgrep) Pattern(pattern string) ([]PID, error) {
 	return pg.pids, pg.err
 }