commit for version used in evaluation of thesis

internal/collector/systemctl.go

@@ -0,0 +1,140 @@
+package collector
+
+import (
+	"bytes"
+	"context"
+	"log"
+	"os/exec"
+	"strings"
+	"sync"
+	"time"
+
+	"codeberg.org/pata1704/guenther/pkg/types"
+)
+
+// SystemctlCollector periodically checks the status of systemd services.
+type SystemctlCollector struct {
+	services   []string
+	interval   time.Duration
+	outputChan chan<- types.ServiceStatus
+	healthChan chan<- types.StageHealth
+
+	wg sync.WaitGroup
+
+	mu        sync.Mutex
+	processed uint64
+}
+
+// NewSystemctlCollector creates a new collector for the given services.
+func NewSystemctlCollector(
+	services []string,
+	interval time.Duration,
+	output chan<- types.ServiceStatus,
+	health chan<- types.StageHealth,
+) *SystemctlCollector {
+	return &SystemctlCollector{
+		services:   services,
+		interval:   interval,
+		outputChan: output,
+		healthChan: health,
+	}
+}
+
+// Start launches the collection loop.
+func (c *SystemctlCollector) Start(ctx context.Context) {
+	if len(c.services) == 0 {
+		log.Println("systemctl: no services configured for monitoring")
+		return
+	}
+
+	c.wg.Go(func() {
+		ticker := time.NewTicker(c.interval)
+		reportTicker := time.NewTicker(5 * time.Second)
+		defer ticker.Stop()
+		defer reportTicker.Stop()
+
+		// Immediate first collection.
+		c.collect()
+
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			case <-ticker.C:
+				c.collect()
+			case <-reportTicker.C:
+				c.emitHealth()
+			}
+		}
+	})
+}
+
+// Wait waits for the collector to stop.
+func (c *SystemctlCollector) Wait() {
+	c.wg.Wait()
+}
+
+func (c *SystemctlCollector) collect() {
+	for _, service := range c.services {
+		status, err := c.getServiceStatus(service)
+		if err != nil {
+			log.Printf("systemctl: error getting status for %s: %v", service, err)
+			continue
+		}
+
+		select {
+		case c.outputChan <- status:
+			c.mu.Lock()
+			c.processed++
+			c.mu.Unlock()
+		default:
+			log.Printf("systemctl: output channel full – dropping status for %s", service)
+		}
+	}
+}
+
+func (c *SystemctlCollector) getServiceStatus(service string) (types.ServiceStatus, error) {
+	// Use systemctl show to get machine-readable properties.
+	cmd := exec.Command("systemctl", "show", "-p", "ActiveState,SubState", service)
+	var out bytes.Buffer
+	cmd.Stdout = &out
+	if err := cmd.Run(); err != nil {
+		return types.ServiceStatus{}, err
+	}
+
+	lines := strings.Split(strings.TrimSpace(out.String()), "\n")
+	status := types.ServiceStatus{
+		Timestamp:   time.Now(),
+		ServiceName: service,
+	}
+
+	for _, line := range lines {
+		parts := strings.SplitN(line, "=", 2)
+		if len(parts) != 2 {
+			continue
+		}
+		switch parts[0] {
+		case "ActiveState":
+			status.ActiveState = parts[1]
+		case "SubState":
+			status.SubState = parts[1]
+		}
+	}
+
+	return status, nil
+}
+
+func (c *SystemctlCollector) emitHealth() {
+	c.mu.Lock()
+	count := c.processed
+	c.mu.Unlock()
+
+	select {
+	case c.healthChan <- types.StageHealth{
+		StageName:       "systemctl_collector",
+		EventsProcessed: count,
+		LastUpdate:      time.Now(),
+	}:
+	default:
+	}
+}