Add windows service name lookup to procstat input (influxdata#4811)

plugins/inputs/procstat/README.md

@@ -11,6 +11,7 @@ Processes can be selected for monitoring using one of several methods:
 - user
 - systemd_unit
 - cgroup
+- win_service
 
 ### Configuration:
 
@@ -30,6 +31,9 @@ Processes can be selected for monitoring using one of several methods:
   ## CGroup name or path
   # cgroup = "systemd/system.slice/nginx.service"
 
+  ## Windows service name
+  # win_service = ""
+
   ## override for process_name
   ## This is optional; default is sourced from /proc/<pid>/status
   # process_name = "bar"
@@ -75,6 +79,7 @@ implemented as a WMI query.  The pattern allows fuzzy matching using only
     - user (when selected)
     - systemd_unit (when defined)
     - cgroup (when defined)
+    - win_service (when defined)
   - fields:
     - cpu_time (int)
     - cpu_time_guest (float)
@@ -139,6 +144,7 @@ implemented as a WMI query.  The pattern allows fuzzy matching using only
     - user (string)
     - systemd_unit (string)
     - cgroup (string)
+    - win_service (string)
   - fields:
     - pid_count (int)
 *NOTE: Resource limit > 2147483647 will be reported as 2147483647.*

plugins/inputs/procstat/procstat.go

@@ -32,6 +32,7 @@ type Procstat struct {
 	SystemdUnit string
 	CGroup      string `toml:"cgroup"`
 	PidTag      bool
+	WinService  string `tom:"win_service"`
 
 	finder PIDFinder
 
@@ -54,6 +55,9 @@ var sampleConfig = `
   ## CGroup name or path
   # cgroup = "systemd/system.slice/nginx.service"
 
+  ## Windows service name
+  # win_service = ""
+
   ## override for process_name
   ## This is optional; default is sourced from /proc/<pid>/status
   # process_name = "bar"
@@ -317,8 +321,11 @@ func (p *Procstat) findPids(acc telegraf.Accumulator) ([]PID, map[string]string,
 	} else if p.CGroup != "" {
 		pids, err = p.cgroupPIDs()
 		tags = map[string]string{"cgroup": p.CGroup}
+	} else if p.WinService != "" {
+		pids, err = p.winServicePIDs()
+		tags = map[string]string{"win_service": p.WinService}
 	} else {
-		err = fmt.Errorf("Either exe, pid_file, user, pattern, systemd_unit, or cgroup must be specified")
+		err = fmt.Errorf("Either exe, pid_file, user, pattern, systemd_unit, cgroup, or win_service must be specified")
 	}
 
 	rTags := make(map[string]string)
@@ -391,6 +398,19 @@ func (p *Procstat) cgroupPIDs() ([]PID, error) {
 	return pids, nil
 }
 
+func (p *Procstat) winServicePIDs() ([]PID, error) {
+	var pids []PID
+
+	pid, err := queryPidWithWinServiceName(p.WinService)
+	if err != nil {
+		return pids, err
+	}
+
+	pids = append(pids, PID(pid))
+
+	return pids, nil
+}
+
 func init() {
 	inputs.Add("procstat", func() telegraf.Input {
 		return &Procstat{}

plugins/inputs/procstat/win_service_notwindows.go

@@ -0,0 +1,11 @@
+// +build !windows
+
+package procstat
+
+import (
+	"fmt"
+)
+
+func queryPidWithWinServiceName(winServiceName string) (uint32, error) {
+	return 0, fmt.Errorf("os not support win_service option")
+}

plugins/inputs/procstat/win_service_windows.go

@@ -0,0 +1,49 @@
+// +build windows
+
+package procstat
+
+import (
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+	"golang.org/x/sys/windows/svc/mgr"
+)
+
+func getService(name string) (*mgr.Service, error) {
+	m, err := mgr.Connect()
+	if err != nil {
+		return nil, err
+	}
+	defer m.Disconnect()
+
+	srv, err := m.OpenService(name)
+	if err != nil {
+		return nil, err
+	}
+
+	return srv, nil
+}
+
+func queryPidWithWinServiceName(winServiceName string) (uint32, error) {
+
+	srv, err := getService(winServiceName)
+	if err != nil {
+		return 0, err
+	}
+
+	var p *windows.SERVICE_STATUS_PROCESS
+	var bytesNeeded uint32
+	var buf []byte
+
+	if err := windows.QueryServiceStatusEx(srv.Handle, windows.SC_STATUS_PROCESS_INFO, nil, 0, &bytesNeeded); err != windows.ERROR_INSUFFICIENT_BUFFER {
+		return 0, err
+	}
+
+	buf = make([]byte, bytesNeeded)
+	p = (*windows.SERVICE_STATUS_PROCESS)(unsafe.Pointer(&buf[0]))
+	if err := windows.QueryServiceStatusEx(srv.Handle, windows.SC_STATUS_PROCESS_INFO, &buf[0], uint32(len(buf)), &bytesNeeded); err != nil {
+		return 0, err
+	}
+
+	return p.ProcessId, nil
+}