feat(inputs.procstat): Obtain process information through supervisor

plugins/inputs/procstat/README.md

@@ -12,6 +12,7 @@ Processes can be selected for monitoring using one of several methods:
 - user
 - systemd_unit
 - cgroup
+- supervisor_unit
 - win_service
 
 ## Global configuration options <!-- @/docs/includes/plugin_config.md -->
@@ -41,6 +42,8 @@ See the [CONFIGURATION.md][CONFIGURATION.md] for more details.
   # include_systemd_children = false
   ## CGroup name or path, supports globs
   # cgroup = "systemd/system.slice/nginx.service"
+  ## Supervisor service names of hypervisorctl management
+  # supervisor_units = ["webserver", "proxy"]
 
   ## Windows service name
   # win_service = ""
@@ -78,6 +81,11 @@ See the [CONFIGURATION.md][CONFIGURATION.md] for more details.
 Preliminary support for Windows has been added, however you may prefer using
 the `win_perf_counters` input plugin as a more mature alternative.
 
+### Darwin specifics
+
+If you use this plugin with `supervisor_units` *and* `pattern` on Darwin, you
+**have to** use the `pgrep` finder as the underlying library relies on `pgrep`.
+
 ### Permissions
 
 Some files or directories may require elevated permissions. As such a user may
@@ -109,6 +117,7 @@ Below are an example set of tags and fields:
     - systemd_unit (when defined)
     - cgroup (when defined)
     - cgroup_full (when cgroup or systemd_unit is used with glob)
+    - supervisor_unit (when defined)
     - win_service (when defined)
   - fields:
     - child_major_faults (int)
@@ -179,6 +188,7 @@ Below are an example set of tags and fields:
     - user
     - systemd_unit
     - cgroup
+    - supervisor_unit
     - win_service
     - result
   - fields:

plugins/inputs/procstat/native_finder.go

@@ -80,6 +80,41 @@ func (pg *NativeFinder) FullPattern(pattern string) ([]PID, error) {
 	return pids, err
 }
 
+// ChildPattern matches children pids on the command line when the process was executed
+func (pg *NativeFinder) ChildPattern(pattern string) ([]PID, error) {
+	regxPattern, err := regexp.Compile(pattern)
+	if err != nil {
+		return nil, fmt.Errorf("compiling regexp failed: %w", err)
+	}
+
+	procs, err := process.Processes()
+	if err != nil {
+		return nil, fmt.Errorf("getting processes failed: %w", err)
+	}
+
+	var pids []PID
+	for _, p := range procs {
+		cmd, err := p.Cmdline()
+		if err != nil || !regxPattern.MatchString(cmd) {
+			continue
+		}
+
+		parent, err := process.NewProcess(p.Pid)
+		if err != nil {
+			return nil, fmt.Errorf("unable to get process %d: %w", p.Pid, err)
+		}
+		children, err := parent.Children()
+		if err != nil {
+			return nil, fmt.Errorf("unable to get children of process %d: %w", p.Pid, err)
+		}
+
+		for _, child := range children {
+			pids = append(pids, PID(child.Pid))
+		}
+	}
+	return pids, err
+}
+
 func (pg *NativeFinder) FastProcessList() ([]*process.Process, error) {
 	pids, err := process.Pids()
 	if err != nil {

plugins/inputs/procstat/native_finder_test.go

@@ -1,29 +1,62 @@
 package procstat
 
 import (
+	"context"
+	"os"
+	"os/exec"
+	"runtime"
 	"testing"
 
 	"github.com/stretchr/testify/require"
 )
 
 func BenchmarkPattern(b *testing.B) {
-	f, err := NewNativeFinder()
+	finder, err := NewNativeFinder()
 	require.NoError(b, err)
 	for n := 0; n < b.N; n++ {
-		_, err := f.Pattern(".*")
-		if err != nil {
-			panic(err)
-		}
+		_, err = finder.Pattern(".*")
+		require.NoError(b, err)
 	}
 }
 
 func BenchmarkFullPattern(b *testing.B) {
-	f, err := NewNativeFinder()
+	finder, err := NewNativeFinder()
 	require.NoError(b, err)
 	for n := 0; n < b.N; n++ {
-		_, err := f.FullPattern(".*")
-		if err != nil {
-			panic(err)
-		}
+		_, err := finder.FullPattern(".*")
+		require.NoError(b, err)
 	}
 }
+
+func TestChildPattern(t *testing.T) {
+	if runtime.GOOS == "windows" || runtime.GOOS == "darwin" {
+		t.Skip("Skipping test on unsupported platform")
+	}
+
+	// Get our own process name
+	parentName, err := os.Executable()
+	require.NoError(t, err)
+
+	// Spawn two child processes and get their PIDs
+	expected := make([]PID, 0, 2)
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	// First process
+	cmd1 := exec.CommandContext(ctx, "/bin/sh")
+	require.NoError(t, cmd1.Start(), "starting first command failed")
+	expected = append(expected, PID(cmd1.Process.Pid))
+
+	// Second process
+	cmd2 := exec.CommandContext(ctx, "/bin/sh")
+	require.NoError(t, cmd2.Start(), "starting first command failed")
+	expected = append(expected, PID(cmd2.Process.Pid))
+
+	// Use the plugin to find the children
+	finder, err := NewNativeFinder()
+	require.NoError(t, err)
+
+	childs, err := finder.ChildPattern(parentName)
+	require.NoError(t, err)
+	require.ElementsMatch(t, expected, childs)
+}

plugins/inputs/procstat/native_finder_windows_test.go

@@ -1,7 +1,6 @@
 package procstat
 
 import (
-	"fmt"
 	"os/user"
 	"testing"
 
@@ -16,7 +15,6 @@ func TestGather_RealPatternIntegration(t *testing.T) {
 	require.NoError(t, err)
 	pids, err := pg.Pattern(`procstat`)
 	require.NoError(t, err)
-	fmt.Println(pids)
 	require.NotEmpty(t, pids)
 }
 
@@ -26,9 +24,9 @@ func TestGather_RealFullPatternIntegration(t *testing.T) {
 	}
 	pg, err := NewNativeFinder()
 	require.NoError(t, err)
+
 	pids, err := pg.FullPattern(`%procstat%`)
 	require.NoError(t, err)
-	fmt.Println(pids)
 	require.NotEmpty(t, pids)
 }
 
@@ -42,6 +40,5 @@ func TestGather_RealUserIntegration(t *testing.T) {
 	require.NoError(t, err)
 	pids, err := pg.UID(currentUser.Username)
 	require.NoError(t, err)
-	fmt.Println(pids)
 	require.NotEmpty(t, pids)
 }

plugins/inputs/procstat/pgrep.go

@@ -53,6 +53,32 @@ func (pg *Pgrep) FullPattern(pattern string) ([]PID, error) {
 	return find(pg.path, args)
 }
 
+func (pg *Pgrep) ChildPattern(pattern string) ([]PID, error) {
+	args := []string{"-P", pattern}
+	out, err := run(pg.path, args)
+	if err != nil {
+		return nil, err
+	}
+
+	pids := []PID{}
+	pid, err := strconv.ParseInt(pattern, 10, 32)
+	if err != nil {
+		return nil, err
+	}
+	pids = append(pids, PID(pid))
+
+	fields := strings.Fields(out)
+	for _, field := range fields {
+		pid, err := strconv.ParseInt(field, 10, 32)
+		if err != nil {
+			return pids, err
+		}
+		pids = append(pids, PID(pid))
+	}
+
+	return pids, nil
+}
+
 func find(path string, args []string) ([]PID, error) {
 	out, err := run(path, args)
 	if err != nil {

plugins/inputs/procstat/process.go

@@ -37,6 +37,7 @@ type PIDFinder interface {
 	Pattern(pattern string) ([]PID, error)
 	UID(user string) ([]PID, error)
 	FullPattern(path string) ([]PID, error)
+	ChildPattern(path string) ([]PID, error)
 }
 
 type Proc struct {