Session 4 complete - RedFlag update management platform

🚩 Private development - version retention only

✅ Complete web dashboard (React + TypeScript + TailwindCSS)
✅ Production-ready server backend (Go + Gin + PostgreSQL)
✅ Linux agent with APT + Docker scanning + local CLI tools
✅ JWT authentication and REST API
✅ Update discovery and approval workflow

🚧 Status: Alpha software - active development
📦 Purpose: Version retention during development
⚠️  Not for public use or deployment

aggregator-agent/internal/cache/local.go

@@ -0,0 +1,129 @@
+package cache
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+	"time"
+
+	"github.com/aggregator-project/aggregator-agent/internal/client"
+	"github.com/google/uuid"
+)
+
+// LocalCache stores scan results locally for offline viewing
+type LocalCache struct {
+	LastScanTime   time.Time              `json:"last_scan_time"`
+	LastCheckIn    time.Time              `json:"last_check_in"`
+	AgentID        uuid.UUID              `json:"agent_id"`
+	ServerURL      string                 `json:"server_url"`
+	UpdateCount    int                    `json:"update_count"`
+	Updates        []client.UpdateReportItem `json:"updates"`
+	AgentStatus    string                 `json:"agent_status"`
+}
+
+// CacheDir is the directory where local cache is stored
+const CacheDir = "/var/lib/aggregator"
+
+// CacheFile is the file where scan results are cached
+const CacheFile = "last_scan.json"
+
+// GetCachePath returns the full path to the cache file
+func GetCachePath() string {
+	return filepath.Join(CacheDir, CacheFile)
+}
+
+// Load reads the local cache from disk
+func Load() (*LocalCache, error) {
+	cachePath := GetCachePath()
+
+	// Check if cache file exists
+	if _, err := os.Stat(cachePath); os.IsNotExist(err) {
+		// Return empty cache if file doesn't exist
+		return &LocalCache{}, nil
+	}
+
+	// Read cache file
+	data, err := os.ReadFile(cachePath)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read cache file: %w", err)
+	}
+
+	var cache LocalCache
+	if err := json.Unmarshal(data, &cache); err != nil {
+		return nil, fmt.Errorf("failed to parse cache file: %w", err)
+	}
+
+	return &cache, nil
+}
+
+// Save writes the local cache to disk
+func (c *LocalCache) Save() error {
+	cachePath := GetCachePath()
+
+	// Ensure cache directory exists
+	if err := os.MkdirAll(CacheDir, 0755); err != nil {
+		return fmt.Errorf("failed to create cache directory: %w", err)
+	}
+
+	// Marshal cache to JSON with indentation
+	data, err := json.MarshalIndent(c, "", "  ")
+	if err != nil {
+		return fmt.Errorf("failed to marshal cache: %w", err)
+	}
+
+	// Write cache file with restricted permissions
+	if err := os.WriteFile(cachePath, data, 0600); err != nil {
+		return fmt.Errorf("failed to write cache file: %w", err)
+	}
+
+	return nil
+}
+
+// UpdateScanResults updates the cache with new scan results
+func (c *LocalCache) UpdateScanResults(updates []client.UpdateReportItem) {
+	c.LastScanTime = time.Now()
+	c.Updates = updates
+	c.UpdateCount = len(updates)
+}
+
+// UpdateCheckIn updates the last check-in time
+func (c *LocalCache) UpdateCheckIn() {
+	c.LastCheckIn = time.Now()
+}
+
+// SetAgentInfo sets agent identification information
+func (c *LocalCache) SetAgentInfo(agentID uuid.UUID, serverURL string) {
+	c.AgentID = agentID
+	c.ServerURL = serverURL
+}
+
+// SetAgentStatus sets the current agent status
+func (c *LocalCache) SetAgentStatus(status string) {
+	c.AgentStatus = status
+}
+
+// IsExpired checks if the cache is older than the specified duration
+func (c *LocalCache) IsExpired(maxAge time.Duration) bool {
+	return time.Since(c.LastScanTime) > maxAge
+}
+
+// GetUpdatesByType returns updates filtered by package type
+func (c *LocalCache) GetUpdatesByType(packageType string) []client.UpdateReportItem {
+	var filtered []client.UpdateReportItem
+	for _, update := range c.Updates {
+		if update.PackageType == packageType {
+			filtered = append(filtered, update)
+		}
+	}
+	return filtered
+}
+
+// Clear clears the cache
+func (c *LocalCache) Clear() {
+	c.LastScanTime = time.Time{}
+	c.LastCheckIn = time.Time{}
+	c.UpdateCount = 0
+	c.Updates = []client.UpdateReportItem{}
+	c.AgentStatus = ""
+}