feat: add notification events handling and MQTT integration

- Implemented notification event publishing with a new NotificationEventPublisher interface.
- Created a noopNotificationEventPublisher for testing purposes.
- Added functionality to publish notification created events via MQTT.
- Introduced a new stream event publisher for handling job logs and updates.
- Added database migration for popup_ads table.
- Created tests for notification events and popup ads functionality.
- Established MQTT connection and publishing helpers for event messages.

internal/transport/mqtt/stream_event_publisher.go

@@ -0,0 +1,187 @@
+package mqtt
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"time"
+
+	pahomqtt "github.com/eclipse/paho.mqtt.golang"
+	"stream.api/internal/dto"
+	"stream.api/internal/service"
+	"stream.api/pkg/logger"
+)
+
+type agentRuntime interface {
+	ListAgentsWithStats() []*dto.AgentWithStats
+}
+
+type streamEventPublisher struct {
+	client     pahomqtt.Client
+	jobService *service.JobService
+	agentRT    agentRuntime
+	logger     logger.Logger
+	prefix     string
+}
+
+func newStreamEventPublisher(jobService *service.JobService, agentRT agentRuntime, appLogger logger.Logger) (*streamEventPublisher, error) {
+	client, err := connectPahoClient(defaultMQTTBrokerURL, fmt.Sprintf("stream-api-%d", time.Now().UnixNano()))
+	if err != nil {
+		return nil, err
+	}
+
+	return &streamEventPublisher{
+		client:     client,
+		jobService: jobService,
+		agentRT:    agentRT,
+		logger:     appLogger,
+		prefix:     defaultMQTTPrefix,
+	}, nil
+}
+
+func (p *streamEventPublisher) start(ctx context.Context) {
+	if p == nil || p.jobService == nil {
+		return
+	}
+	go p.consumeLogs(ctx)
+	go p.consumeJobUpdates(ctx)
+	go p.consumeResources(ctx)
+}
+
+func (p *streamEventPublisher) consumeLogs(ctx context.Context) {
+	ch, err := p.jobService.SubscribeJobLogs(ctx, "")
+	if err != nil {
+		p.logger.Error("Failed to subscribe job logs for MQTT", "error", err)
+		return
+	}
+
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case entry, ok := <-ch:
+			if !ok {
+				return
+			}
+			if err := publishMQTTJSON(p.client, p.logTopic(entry.JobID), entry); err != nil {
+				p.logger.Error("Failed to publish MQTT job log", "error", err, "job_id", entry.JobID)
+			}
+		}
+	}
+}
+
+func (p *streamEventPublisher) consumeJobUpdates(ctx context.Context) {
+	ch, err := p.jobService.SubscribeJobUpdates(ctx)
+	if err != nil {
+		p.logger.Error("Failed to subscribe job updates for MQTT", "error", err)
+		return
+	}
+
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case msg, ok := <-ch:
+			if !ok {
+				return
+			}
+
+			var payload map[string]any
+			if err := json.Unmarshal([]byte(msg), &payload); err != nil {
+				p.logger.Error("Failed to decode MQTT job update payload", "error", err)
+				continue
+			}
+
+			jobID, _ := payload["job_id"].(string)
+			if err := p.publishEvent("job_update", payload, jobID); err != nil {
+				p.logger.Error("Failed to publish MQTT job update", "error", err, "job_id", jobID)
+			}
+		}
+	}
+}
+
+func (p *streamEventPublisher) consumeResources(ctx context.Context) {
+	ch, err := p.jobService.SubscribeSystemResources(ctx)
+	if err != nil {
+		p.logger.Error("Failed to subscribe resources for MQTT", "error", err)
+		return
+	}
+
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case entry, ok := <-ch:
+			if !ok {
+				return
+			}
+
+			if err := p.publishEvent("resource_update", entry, ""); err != nil {
+				p.logger.Error("Failed to publish MQTT resource update", "error", err, "agent_id", entry.AgentID)
+			}
+
+			agent := p.findAgent(entry.AgentID)
+			if agent == nil {
+				continue
+			}
+			if err := p.publishEvent("agent_update", mapAgentPayload(agent), ""); err != nil {
+				p.logger.Error("Failed to publish MQTT agent update", "error", err, "agent_id", entry.AgentID)
+			}
+		}
+	}
+}
+
+func (p *streamEventPublisher) findAgent(agentID string) *dto.AgentWithStats {
+	if p == nil || p.agentRT == nil {
+		return nil
+	}
+	for _, agent := range p.agentRT.ListAgentsWithStats() {
+		if agent != nil && agent.Agent != nil && agent.Agent.ID == agentID {
+			return agent
+		}
+	}
+	return nil
+}
+
+func (p *streamEventPublisher) publishEvent(eventType string, payload any, jobID string) error {
+	message := mqttEvent{Type: eventType, Payload: payload}
+	if jobID != "" {
+		if err := publishMQTTJSON(p.client, p.jobTopic(jobID), message); err != nil {
+			return err
+		}
+	}
+	return publishMQTTJSON(p.client, p.eventsTopic(), message)
+}
+
+func (p *streamEventPublisher) logTopic(jobID string) string {
+	return fmt.Sprintf("%s/logs/%s", p.prefix, jobID)
+}
+
+func (p *streamEventPublisher) jobTopic(jobID string) string {
+	return fmt.Sprintf("%s/job/%s", p.prefix, jobID)
+}
+
+func (p *streamEventPublisher) eventsTopic() string {
+	return fmt.Sprintf("%s/events", p.prefix)
+}
+
+func mapAgentPayload(agent *dto.AgentWithStats) map[string]any {
+	if agent == nil || agent.Agent == nil {
+		return map[string]any{}
+	}
+	return map[string]any{
+		"id":               agent.Agent.ID,
+		"name":             agent.Name,
+		"platform":         agent.Platform,
+		"backend":          agent.Backend,
+		"version":          agent.Version,
+		"capacity":         agent.Capacity,
+		"status":           string(agent.Status),
+		"cpu":              agent.CPU,
+		"ram":              agent.RAM,
+		"last_heartbeat":   agent.LastHeartbeat,
+		"created_at":       agent.CreatedAt,
+		"updated_at":       agent.UpdatedAt,
+		"active_job_count": agent.ActiveJobCount,
+	}
+}