feat(inputs.systemd_units): Support user scoped units (#12053)

plugins/inputs/systemd_units/README.md

@@ -69,6 +69,7 @@ These metrics are available in both modes:
     - load (string, load state)
     - active (string, active state)
     - sub (string, sub state)
+    - user (string, username when `scope = "user"`, empty when `scope = "system"`)
   - fields:
     - load_code (int, see below)
     - active_code (int, see below)
@@ -198,15 +199,15 @@ were removed, tables are hex aligned to keep some space for future values
 ### Output in non-detailed mode
 
 ```text
-systemd_units,host=host1.example.com,name=dbus.service,load=loaded,active=active,sub=running load_code=0i,active_code=0i,sub_code=0i 1533730725000000000
-systemd_units,host=host1.example.com,name=networking.service,load=loaded,active=failed,sub=failed load_code=0i,active_code=3i,sub_code=12i 1533730725000000000
-systemd_units,host=host1.example.com,name=ssh.service,load=loaded,active=active,sub=running load_code=0i,active_code=0i,sub_code=0i 1533730725000000000
+systemd_units,host=host1.example.com,name=dbus.service,load=loaded,active=active,sub=running,user=telegraf load_code=0i,active_code=0i,sub_code=0i 1533730725000000000
+systemd_units,host=host1.example.com,name=networking.service,load=loaded,active=failed,sub=failed,user=telegraf load_code=0i,active_code=3i,sub_code=12i 1533730725000000000
+systemd_units,host=host1.example.com,name=ssh.service,load=loaded,active=active,sub=running,user=telegraf load_code=0i,active_code=0i,sub_code=0i 1533730725000000000
 ```
 
 ### Output in detailed mode
 
 ```text
-systemd_units,active=active,host=host1.example.com,load=loaded,name=dbus.service,sub=running,preset=disabled,state=static active_code=0i,load_code=0i,mem_avail=6470856704i,mem_current=2691072i,mem_peak=3895296i,pid=481i,restarts=0i,status_errno=0i,sub_code=0i,swap_current=794624i,swap_peak=884736i 1533730725000000000
-systemd_units,active=inactive,host=host1.example.com,load=not-found,name=networking.service,sub=dead active_code=2i,load_code=2i,pid=0i,restarts=0i,status_errno=0i,sub_code=1i 1533730725000000000
-systemd_units,active=active,host=host1.example.com,load=loaded,name=pcscd.service,sub=running,preset=disabled,state=indirect active_code=0i,load_code=0i,mem_avail=6370541568i,mem_current=512000i,mem_peak=4399104i,pid=1673i,restarts=0i,status_errno=0i,sub_code=0i,swap_current=3149824i,swap_peak=3149824i 1533730725000000000
+systemd_units,active=active,host=host1.example.com,load=loaded,name=dbus.service,sub=running,preset=disabled,state=static,user=telegraf active_code=0i,load_code=0i,mem_avail=6470856704i,mem_current=2691072i,mem_peak=3895296i,pid=481i,restarts=0i,status_errno=0i,sub_code=0i,swap_current=794624i,swap_peak=884736i 1533730725000000000
+systemd_units,active=inactive,host=host1.example.com,load=not-found,name=networking.service,sub=dead,user=telegraf active_code=2i,load_code=2i,pid=0i,restarts=0i,status_errno=0i,sub_code=1i 1533730725000000000
+systemd_units,active=active,host=host1.example.com,load=loaded,name=pcscd.service,sub=running,preset=disabled,state=indirect,user=telegraf active_code=0i,load_code=0i,mem_avail=6370541568i,mem_current=512000i,mem_peak=4399104i,pid=1673i,restarts=0i,status_errno=0i,sub_code=0i,swap_current=3149824i,swap_peak=3149824i 1533730725000000000
 ```

plugins/inputs/systemd_units/systemd_units.go

@@ -17,6 +17,7 @@ var sampleConfig string
 type SystemdUnits struct {
 	Pattern         string          `toml:"pattern"`
 	UnitType        string          `toml:"unittype"`
+	Scope           string          `toml:"scope"`
 	Details         bool            `toml:"details"`
 	CollectDisabled bool            `toml:"collect_disabled_units"`
 	Timeout         config.Duration `toml:"timeout"`

plugins/inputs/systemd_units/systemd_units_linux.go

@@ -6,6 +6,7 @@ import (
 	"context"
 	"fmt"
 	"math"
+	"os"
 	"path"
 	"strings"
 	"time"
@@ -131,6 +132,8 @@ type archParams struct {
 	pattern      []string
 	filter       filter.Filter
 	unitTypeDBus string
+	scope        string
+	user         string
 }
 
 func (s *SystemdUnits) Init() error {
@@ -158,12 +161,34 @@ func (s *SystemdUnits) Init() error {
 	}
 	s.filter = f
 
+	switch s.Scope {
+	case "", "system":
+		s.scope = "system"
+		s.user = ""
+	case "user":
+		s.scope = "user"
+		s.user = os.Getenv("USER")
+	default:
+		return fmt.Errorf("invalid 'scope' %q", s.Scope)
+	}
+
 	return nil
 }
 
 func (s *SystemdUnits) Start(telegraf.Accumulator) error {
+	var (
+		client *dbus.Conn
+		err    error
+	)
+
 	ctx := context.Background()
-	client, err := dbus.NewSystemConnectionContext(ctx)
+
+	switch s.scope {
+	case "user":
+		client, err = dbus.NewUserConnectionContext(ctx)
+	default:
+		client, err = dbus.NewSystemConnectionContext(ctx)
+	}
 	if err != nil {
 		return err
 	}
@@ -320,6 +345,7 @@ func (s *SystemdUnits) Gather(acc telegraf.Accumulator) error {
 			"load":   state.LoadState,
 			"active": state.ActiveState,
 			"sub":    state.SubState,
+			"user":   s.user,
 		}
 
 		fields := map[string]interface{}{

plugins/inputs/systemd_units/systemd_units_test.go

@@ -7,6 +7,7 @@ import (
 	"errors"
 	"fmt"
 	"math"
+	"os"
 	"strings"
 	"testing"
 	"time"
@@ -38,6 +39,52 @@ func TestDefaultPattern(t *testing.T) {
 	require.Equal(t, "*", plugin.Pattern)
 }
 
+func TestDefaultScope(t *testing.T) {
+	tests := []struct {
+		name     string
+		scope    string
+		expected map[string]string
+	}{
+		{
+			scope: "",
+			expected: map[string]string{
+				"scope": "system",
+				"user":  "",
+			},
+		},
+		{
+			scope: "system",
+			expected: map[string]string{
+				"scope": "system",
+				"user":  "",
+			},
+		},
+		{
+			scope: "user",
+			expected: map[string]string{
+				"scope": "user",
+				"user":  os.Getenv("USER"),
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			plugin := &SystemdUnits{
+				Scope: tt.scope,
+			}
+			require.NoError(t, plugin.Init())
+			if tt.expected["scope"] != plugin.scope {
+				t.Fatalf("Incorrect scope set: %q", plugin.scope)
+			}
+
+			if tt.expected["user"] != plugin.user {
+				t.Fatalf("Wrong username established: %q", plugin.user)
+			}
+		})
+	}
+}
+
 func TestListFiles(t *testing.T) {
 	tests := []struct {
 		name        string
@@ -68,6 +115,7 @@ func TestListFiles(t *testing.T) {
 						"load":   "loaded",
 						"active": "active",
 						"sub":    "running",
+						"user":   "",
 					},
 					map[string]interface{}{
 						"load_code":   0,
@@ -100,6 +148,7 @@ func TestListFiles(t *testing.T) {
 						"load":   "loaded",
 						"active": "active",
 						"sub":    "exited",
+						"user":   "",
 					},
 					map[string]interface{}{
 						"load_code":   0,
@@ -132,6 +181,7 @@ func TestListFiles(t *testing.T) {
 						"load":   "loaded",
 						"active": "failed",
 						"sub":    "failed",
+						"user":   "",
 					},
 					map[string]interface{}{
 						"load_code":   0,
@@ -164,6 +214,7 @@ func TestListFiles(t *testing.T) {
 						"load":   "not-found",
 						"active": "inactive",
 						"sub":    "dead",
+						"user":   "",
 					},
 					map[string]interface{}{
 						"load_code":   2,
@@ -281,6 +332,7 @@ func TestShow(t *testing.T) {
 						"sub":    "running",
 						"state":  "enabled",
 						"preset": "disabled",
+						"user":   "",
 					},
 					map[string]interface{}{
 						"load_code":    0,
@@ -329,6 +381,7 @@ func TestShow(t *testing.T) {
 						"sub":    "exited",
 						"state":  "enabled",
 						"preset": "disabled",
+						"user":   "",
 					},
 					map[string]interface{}{
 						"load_code":    0,
@@ -381,6 +434,7 @@ func TestShow(t *testing.T) {
 						"sub":    "failed",
 						"state":  "enabled",
 						"preset": "disabled",
+						"user":   "",
 					},
 					map[string]interface{}{
 						"load_code":    0,
@@ -426,6 +480,7 @@ func TestShow(t *testing.T) {
 						"sub":    "dead",
 						"state":  "enabled",
 						"preset": "disabled",
+						"user":   "",
 					},
 					map[string]interface{}{
 						"load_code":    2,
@@ -496,6 +551,7 @@ func TestShow(t *testing.T) {
 						"sub":    "dead",
 						"state":  "disabled",
 						"preset": "disabled",
+						"user":   "",
 					},
 					map[string]interface{}{
 						"load_code":    0,
@@ -569,6 +625,7 @@ func TestMultiInstance(t *testing.T) {
 						"load":   "loaded",
 						"active": "active",
 						"sub":    "running",
+						"user":   "",
 					},
 					map[string]interface{}{
 						"load_code":   0,
@@ -584,6 +641,7 @@ func TestMultiInstance(t *testing.T) {
 						"load":   "loaded",
 						"active": "active",
 						"sub":    "running",
+						"user":   "",
 					},
 					map[string]interface{}{
 						"load_code":   0,
@@ -599,6 +657,7 @@ func TestMultiInstance(t *testing.T) {
 						"load":   "loaded",
 						"active": "active",
 						"sub":    "exited",
+						"user":   "",
 					},
 					map[string]interface{}{
 						"load_code":   0,
@@ -620,6 +679,7 @@ func TestMultiInstance(t *testing.T) {
 						"load":   "loaded",
 						"active": "active",
 						"sub":    "running",
+						"user":   "",
 					},
 					map[string]interface{}{
 						"load_code":   0,
@@ -635,6 +695,7 @@ func TestMultiInstance(t *testing.T) {
 						"load":   "loaded",
 						"active": "active",
 						"sub":    "exited",
+						"user":   "",
 					},
 					map[string]interface{}{
 						"load_code":   0,
@@ -656,6 +717,7 @@ func TestMultiInstance(t *testing.T) {
 						"load":   "loaded",
 						"active": "active",
 						"sub":    "exited",
+						"user":   "",
 					},
 					map[string]interface{}{
 						"load_code":   0,
@@ -677,6 +739,7 @@ func TestMultiInstance(t *testing.T) {
 						"load":   "loaded",
 						"active": "inactive",
 						"sub":    "dead",
+						"user":   "",
 					},
 					map[string]interface{}{
 						"load_code":   0,
@@ -698,6 +761,7 @@ func TestMultiInstance(t *testing.T) {
 						"load":   "stub",
 						"active": "inactive",
 						"sub":    "dead",
+						"user":   "",
 					},
 					map[string]interface{}{
 						"load_code":   1,
@@ -966,6 +1030,7 @@ func oldParseListUnits(line string) ([]telegraf.Metric, error) {
 		"load":   load,
 		"active": active,
 		"sub":    sub,
+		"user":   "",
 	}
 
 	var (