feat: big ahh commit

- agent+proto+backend: transfer service status
- agent: fix returning empty message on nonzero exit status
- backend: refactor collector+commander and handlers dependent on them: implement agent accounting via grpc stats handler

backend/internal/grpcsrv/collector/collector.go

@@ -4,7 +4,6 @@ import (
 	"fmt"
 	"io"
 	"log"
-	"sync"
 	"time"
 
 	"gitea.d3m0k1d.ru/d3m0k1d/HellreigN/backend/internal/repository"
@@ -13,26 +12,19 @@ import (
 	"google.golang.org/grpc/metadata"
 )
 
+// Collector handles log streaming from connected agents.
 type Collector struct {
 	proto.UnimplementedCollectorServer
 	logRepo       *repository.LogRepository
-	agents        map[string]*Agent
-	mu            sync.RWMutex
+	tracker       *ConnTracker
 	batchSize     int
 	flushInterval time.Duration
 }
 
-type Agent struct {
-	ID          string
-	Label       string
-	Services    []string
-	ConnectedAt time.Time
-}
-
-func New(logRepo *repository.LogRepository) *Collector {
+func New(logRepo *repository.LogRepository, tracker *ConnTracker) *Collector {
 	return &Collector{
 		logRepo:       logRepo,
-		agents:        make(map[string]*Agent),
+		tracker:       tracker,
 		batchSize:     100,
 		flushInterval: 2 * time.Second,
 	}
@@ -56,27 +48,15 @@ func (c *Collector) Stream(stream proto.Collector_StreamServer) error {
 	}
 	service := serviceVals[0]
 
-	servicesVals := md["services"]
-	var services []string
-	if len(servicesVals) > 0 {
-		services = servicesVals
-	}
-
-	// Register agent
-	c.mu.Lock()
-	c.agents[agentName] = &Agent{
+	agent := &Agent{
 		ID:          agentName,
 		Label:       agentName,
-		Services:    services,
+		Services:    make([]Service, 0),
 		ConnectedAt: time.Now(),
 	}
-	c.mu.Unlock()
 
-	defer func() {
-		c.mu.Lock()
-		delete(c.agents, agentName)
-		c.mu.Unlock()
-	}()
+	c.tracker.Register(agent)
+	defer c.tracker.Unregister(agent.ID)
 
 	log.Printf("Agent %s connected, streaming logs for service: %s", agentName, service)
 
@@ -139,7 +119,6 @@ func (c *Collector) Stream(stream proto.Collector_StreamServer) error {
 	for {
 		select {
 		case <-stream.Context().Done():
-			// Context cancelled, flush remaining
 			_ = flush()
 			return stream.Context().Err()
 		case <-ticker.C:
@@ -162,7 +141,6 @@ func (c *Collector) Stream(stream proto.Collector_StreamServer) error {
 			}
 		case err := <-errCh:
 			if err == io.EOF {
-				// Client closed stream
 				return flush()
 			}
 			return fmt.Errorf("failed to receive: %w", err)
@@ -170,19 +148,12 @@ func (c *Collector) Stream(stream proto.Collector_StreamServer) error {
 	}
 }
 
+// GetAgent delegates to the tracker.
 func (c *Collector) GetAgent(name string) (*Agent, bool) {
-	c.mu.RLock()
-	defer c.mu.RUnlock()
-	a, ok := c.agents[name]
-	return a, ok
+	return c.tracker.GetAgent(name)
 }
 
+// Agents delegates to the tracker.
 func (c *Collector) Agents() []*Agent {
-	c.mu.RLock()
-	defer c.mu.RUnlock()
-	result := make([]*Agent, 0, len(c.agents))
-	for _, a := range c.agents {
-		result = append(result, a)
-	}
-	return result
+	return c.tracker.Agents()
 }