RedFlag Agent - Code Implementation Examples

1. Main Loop (Entry Point)

File: /home/memory/Desktop/Projects/RedFlag/aggregator-agent/cmd/agent/main.go
Lines: 410-549

The agent's main loop runs continuously, checking in with the server at regular intervals:

// Lines 410-549: Main check-in loop
for {
    // Add jitter to prevent thundering herd
    jitter := time.Duration(rand.Intn(30)) * time.Second
    time.Sleep(jitter)

    // Check if we need to send detailed system info update (hourly)
    if time.Since(lastSystemInfoUpdate) >= systemInfoUpdateInterval {
        log.Printf("Updating detailed system information...")
        if err := reportSystemInfo(apiClient, cfg); err != nil {
            log.Printf("Failed to report system info: %v\n", err)
        } else {
            lastSystemInfoUpdate = time.Now()
            log.Printf("✓ System information updated\n")
        }
    }

    log.Printf("Checking in with server... (Agent v%s)", AgentVersion)

    // Collect lightweight system metrics (every check-in)
    sysMetrics, err := system.GetLightweightMetrics()
    var metrics *client.SystemMetrics
    if err == nil {
        metrics = &client.SystemMetrics{
            CPUPercent:    sysMetrics.CPUPercent,
            MemoryPercent: sysMetrics.MemoryPercent,
            MemoryUsedGB:  sysMetrics.MemoryUsedGB,
            MemoryTotalGB: sysMetrics.MemoryTotalGB,
            DiskUsedGB:    sysMetrics.DiskUsedGB,
            DiskTotalGB:   sysMetrics.DiskTotalGB,
            DiskPercent:   sysMetrics.DiskPercent,
            Uptime:        sysMetrics.Uptime,
            Version:       AgentVersion,
        }
    }

    // Get commands from server
    commands, err := apiClient.GetCommands(cfg.AgentID, metrics)
    if err != nil {
        // Handle token renewal if needed
        // ... error handling code ...
    }

    // Process each command
    for _, cmd := range commands {
        log.Printf("Processing command: %s (%s)\n", cmd.Type, cmd.ID)

        switch cmd.Type {
        case "scan_updates":
            if err := handleScanUpdates(...); err != nil {
                log.Printf("Error scanning updates: %v\n", err)
            }
        case "install_updates":
            if err := handleInstallUpdates(...); err != nil {
                log.Printf("Error installing updates: %v\n", err)
            }
        // ... other command types ...
        }
    }

    // Wait for next check-in
    time.Sleep(time.Duration(getCurrentPollingInterval(cfg)) * time.Second)
}

2. The Monolithic handleScanUpdates Function

File: /home/memory/Desktop/Projects/RedFlag/aggregator-agent/cmd/agent/main.go
Lines: 551-709

This function orchestrates all scanner subsystems in a monolithic manner:

func handleScanUpdates(
    apiClient *client.Client, cfg *config.Config, 
    aptScanner *scanner.APTScanner, dnfScanner *scanner.DNFScanner, 
    dockerScanner *scanner.DockerScanner, 
    windowsUpdateScanner *scanner.WindowsUpdateScanner, 
    wingetScanner *scanner.WingetScanner, 
    commandID string) error {
    
    log.Println("Scanning for updates...")

    var allUpdates []client.UpdateReportItem
    var scanErrors []string
    var scanResults []string

    // MONOLITHIC PATTERN 1: APT Scanner (lines 559-574)
    if aptScanner.IsAvailable() {
        log.Println("  - Scanning APT packages...")
        updates, err := aptScanner.Scan()
        if err != nil {
            errorMsg := fmt.Sprintf("APT scan failed: %v", err)
            log.Printf("    %s\n", errorMsg)
            scanErrors = append(scanErrors, errorMsg)
        } else {
            resultMsg := fmt.Sprintf("Found %d APT updates", len(updates))
            log.Printf("    %s\n", resultMsg)
            scanResults = append(scanResults, resultMsg)
            allUpdates = append(allUpdates, updates...)
        }
    } else {
        scanResults = append(scanResults, "APT scanner not available")
    }

    // MONOLITHIC PATTERN 2: DNF Scanner (lines 576-592)
    // [SAME PATTERN REPEATS - lines 576-592]
    if dnfScanner.IsAvailable() {
        log.Println("  - Scanning DNF packages...")
        updates, err := dnfScanner.Scan()
        if err != nil {
            errorMsg := fmt.Sprintf("DNF scan failed: %v", err)
            log.Printf("    %s\n", errorMsg)
            scanErrors = append(scanErrors, errorMsg)
        } else {
            resultMsg := fmt.Sprintf("Found %d DNF updates", len(updates))
            log.Printf("    %s\n", resultMsg)
            scanResults = append(scanResults, resultMsg)
            allUpdates = append(allUpdates, updates...)
        }
    } else {
        scanResults = append(scanResults, "DNF scanner not available")
    }

    // MONOLITHIC PATTERN 3: Docker Scanner (lines 594-610)
    // [SAME PATTERN REPEATS - lines 594-610]
    if dockerScanner != nil && dockerScanner.IsAvailable() {
        log.Println("  - Scanning Docker images...")
        updates, err := dockerScanner.Scan()
        if err != nil {
            errorMsg := fmt.Sprintf("Docker scan failed: %v", err)
            log.Printf("    %s\n", errorMsg)
            scanErrors = append(scanErrors, errorMsg)
        } else {
            resultMsg := fmt.Sprintf("Found %d Docker image updates", len(updates))
            log.Printf("    %s\n", resultMsg)
            scanResults = append(scanResults, resultMsg)
            allUpdates = append(allUpdates, updates...)
        }
    } else {
        scanResults = append(scanResults, "Docker scanner not available")
    }

    // MONOLITHIC PATTERN 4: Windows Update Scanner (lines 612-628)
    // [SAME PATTERN REPEATS - lines 612-628]
    if windowsUpdateScanner.IsAvailable() {
        log.Println("  - Scanning Windows updates...")
        updates, err := windowsUpdateScanner.Scan()
        if err != nil {
            errorMsg := fmt.Sprintf("Windows Update scan failed: %v", err)
            log.Printf("    %s\n", errorMsg)
            scanErrors = append(scanErrors, errorMsg)
        } else {
            resultMsg := fmt.Sprintf("Found %d Windows updates", len(updates))
            log.Printf("    %s\n", resultMsg)
            scanResults = append(scanResults, resultMsg)
            allUpdates = append(allUpdates, updates...)
        }
    } else {
        scanResults = append(scanResults, "Windows Update scanner not available")
    }

    // MONOLITHIC PATTERN 5: Winget Scanner (lines 630-646)
    // [SAME PATTERN REPEATS - lines 630-646]
    if wingetScanner.IsAvailable() {
        log.Println("  - Scanning Winget packages...")
        updates, err := wingetScanner.Scan()
        if err != nil {
            errorMsg := fmt.Sprintf("Winget scan failed: %v", err)
            log.Printf("    %s\n", errorMsg)
            scanErrors = append(scanErrors, errorMsg)
        } else {
            resultMsg := fmt.Sprintf("Found %d Winget package updates", len(updates))
            log.Printf("    %s\n", resultMsg)
            scanResults = append(scanResults, resultMsg)
            allUpdates = append(allUpdates, updates...)
        }
    } else {
        scanResults = append(scanResults, "Winget scanner not available")
    }

    // Report scan results (lines 648-677)
    success := len(allUpdates) > 0 || len(scanErrors) == 0
    var combinedOutput string

    if len(scanResults) > 0 {
        combinedOutput += "Scan Results:\n" + strings.Join(scanResults, "\n")
    }
    if len(scanErrors) > 0 {
        if combinedOutput != "" {
            combinedOutput += "\n"
        }
        combinedOutput += "Scan Errors:\n" + strings.Join(scanErrors, "\n")
    }
    if len(allUpdates) > 0 {
        if combinedOutput != "" {
            combinedOutput += "\n"
        }
        combinedOutput += fmt.Sprintf("Total Updates Found: %d", len(allUpdates))
    }

    // Create scan log entry
    logReport := client.LogReport{
        CommandID:       commandID,
        Action:          "scan_updates",
        Result:          map[bool]string{true: "success", false: "failure"}[success],
        Stdout:          combinedOutput,
        Stderr:          strings.Join(scanErrors, "\n"),
        ExitCode:        map[bool]int{true: 0, false: 1}[success],
        DurationSeconds: 0,
    }

    // Report the scan log
    if err := apiClient.ReportLog(cfg.AgentID, logReport); err != nil {
        log.Printf("Failed to report scan log: %v\n", err)
    }

    // Report updates (lines 686-708)
    if len(allUpdates) > 0 {
        report := client.UpdateReport{
            CommandID: commandID,
            Timestamp: time.Now(),
            Updates:   allUpdates,
        }

        if err := apiClient.ReportUpdates(cfg.AgentID, report); err != nil {
            return fmt.Errorf("failed to report updates: %w", err)
        }

        log.Printf("✓ Reported %d updates to server\n", len(allUpdates))
    } else {
        log.Println("✓ No updates found")
    }

    return nil
}

Key Issues:

Pattern repeats 5 times verbatim (lines 559-646)
No abstraction for common scanner pattern
Sequential execution (each scanner waits for previous)
Tight coupling between orchestrator and individual scanners
All error handling mixed with business logic

3. Modular Scanner - APT Implementation

File: /home/memory/Desktop/Projects/RedFlag/aggregator-agent/internal/scanner/apt.go
Lines: 1-91

Individual scanners ARE modular:

package scanner

// APTScanner scans for APT package updates
type APTScanner struct{}

// NewAPTScanner creates a new APT scanner
func NewAPTScanner() *APTScanner {
    return &APTScanner{}
}

// IsAvailable checks if APT is available on this system
func (s *APTScanner) IsAvailable() bool {
    _, err := exec.LookPath("apt")
    return err == nil
}

// Scan scans for available APT updates
func (s *APTScanner) Scan() ([]client.UpdateReportItem, error) {
    // Update package cache (sudo may be required, but try anyway)
    updateCmd := exec.Command("apt-get", "update")
    updateCmd.Run() // Ignore errors

    // Get upgradable packages
    cmd := exec.Command("apt", "list", "--upgradable")
    output, err := cmd.Output()
    if err != nil {
        return nil, fmt.Errorf("failed to run apt list: %w", err)
    }

    return parseAPTOutput(output)
}

func parseAPTOutput(output []byte) ([]client.UpdateReportItem, error) {
    var updates []client.UpdateReportItem
    scanner := bufio.NewScanner(bytes.NewReader(output))

    // Regex to parse apt output
    re := regexp.MustCompile(`^([^\s/]+)/([^\s]+)\s+([^\s]+)\s+([^\s]+)\s+\[upgradable from:\s+([^\]]+)\]`)

    for scanner.Scan() {
        line := scanner.Text()
        if strings.HasPrefix(line, "Listing...") {
            continue
        }

        matches := re.FindStringSubmatch(line)
        if len(matches) < 6 {
            continue
        }

        packageName := matches[1]
        repository := matches[2]
        newVersion := matches[3]
        oldVersion := matches[5]

        // Determine severity (simplified)
        severity := "moderate"
        if strings.Contains(repository, "security") {
            severity = "important"
        }

        update := client.UpdateReportItem{
            PackageType:      "apt",
            PackageName:      packageName,
            CurrentVersion:   oldVersion,
            AvailableVersion: newVersion,
            Severity:         severity,
            RepositorySource: repository,
            Metadata: map[string]interface{}{
                "architecture": matches[4],
            },
        }

        updates = append(updates, update)
    }

    return updates, nil
}

Good Aspects:

Self-contained in single file
Clear interface (IsAvailable, Scan)
No dependencies on other scanners
Error handling encapsulated
Could be swapped out easily

4. Complex Scanner - Windows Update (WUA API)

File: /home/memory/Desktop/Projects/RedFlag/aggregator-agent/internal/scanner/windows_wua.go
Lines: 33-67, 70-211

// Scan scans for available Windows updates using WUA API
func (s *WindowsUpdateScannerWUA) Scan() ([]client.UpdateReportItem, error) {
    if !s.IsAvailable() {
        return nil, fmt.Errorf("WUA scanner is only available on Windows")
    }

    // Initialize COM
    comshim.Add(1)
    defer comshim.Done()

    ole.CoInitializeEx(0, ole.COINIT_APARTMENTTHREADED|ole.COINIT_SPEED_OVER_MEMORY)
    defer ole.CoUninitialize()

    // Create update session
    session, err := windowsupdate.NewUpdateSession()
    if err != nil {
        return nil, fmt.Errorf("failed to create Windows Update session: %w", err)
    }

    // Create update searcher
    searcher, err := session.CreateUpdateSearcher()
    if err != nil {
        return nil, fmt.Errorf("failed to create update searcher: %w", err)
    }

    // Search for available updates (IsInstalled=0 means not installed)
    searchCriteria := "IsInstalled=0 AND IsHidden=0"
    result, err := searcher.Search(searchCriteria)
    if err != nil {
        return nil, fmt.Errorf("failed to search for updates: %w", err)
    }

    // Convert results to our format
    updates := s.convertWUAResult(result)
    return updates, nil
}

// Convert results - rich metadata extraction (lines 70-211)
func (s *WindowsUpdateScannerWUA) convertWUAUpdate(update *windowsupdate.IUpdate) *client.UpdateReportItem {
    // Get update information
    title := update.Title
    description := update.Description
    kbArticles := s.getKBArticles(update)
    updateIdentity := update.Identity

    // Use MSRC severity if available
    severity := s.mapMsrcSeverity(update.MsrcSeverity)
    if severity == "" {
        severity = s.determineSeverityFromCategories(update)
    }

    // Create metadata with WUA-specific information
    metadata := map[string]interface{}{
        "package_manager": "windows_update",
        "detected_via":    "wua_api",
        "kb_articles":     kbArticles,
        "update_identity": updateIdentity.UpdateID,
        "revision_number": updateIdentity.RevisionNumber,
        "download_size":   update.MaxDownloadSize,
        "api_source":      "windows_update_agent",
        "scan_timestamp":  time.Now().Format(time.RFC3339),
    }

    // Add MSRC severity if available
    if update.MsrcSeverity != "" {
        metadata["msrc_severity"] = update.MsrcSeverity
    }

    // Add security bulletin IDs (includes CVEs)
    if len(update.SecurityBulletinIDs) > 0 {
        metadata["security_bulletins"] = update.SecurityBulletinIDs
        cveList := make([]string, 0)
        for _, bulletin := range update.SecurityBulletinIDs {
            if strings.HasPrefix(bulletin, "CVE-") {
                cveList = append(cveList, bulletin)
            }
        }
        if len(cveList) > 0 {
            metadata["cve_list"] = cveList
        }
    }

    // ... more metadata extraction ...

    updateItem := &client.UpdateReportItem{
        PackageType:        "windows_update",
        PackageName:        title,
        PackageDescription: description,
        CurrentVersion:     currentVersion,
        AvailableVersion:   availableVersion,
        Severity:           severity,
        RepositorySource:   "Microsoft Update",
        Metadata:           metadata,
    }

    return updateItem
}

Key Characteristics:

Complex internal logic but clean external interface
Rich metadata extraction (KB articles, CVEs, MSRC severity)
Windows-specific (COM interop)
Still follows IsAvailable/Scan pattern
Encapsulates complexity

5. System Info Reporting (Hourly)

File: /home/memory/Desktop/Projects/RedFlag/aggregator-agent/cmd/agent/main.go
Lines: 1357-1407

// reportSystemInfo collects and reports detailed system information
func reportSystemInfo(apiClient *client.Client, cfg *config.Config) error {
    // Collect detailed system information
    sysInfo, err := system.GetSystemInfo(AgentVersion)
    if err != nil {
        return fmt.Errorf("failed to get system info: %w", err)
    }

    // Create system info report
    report := client.SystemInfoReport{
        Timestamp:   time.Now(),
        CPUModel:    sysInfo.CPUInfo.ModelName,
        CPUCores:    sysInfo.CPUInfo.Cores,
        CPUThreads:  sysInfo.CPUInfo.Threads,
        MemoryTotal: sysInfo.MemoryInfo.Total,
        DiskTotal:   uint64(0),
        DiskUsed:    uint64(0),
        IPAddress:   sysInfo.IPAddress,
        Processes:   sysInfo.RunningProcesses,
        Uptime:      sysInfo.Uptime,
        Metadata:    make(map[string]interface{}),
    }

    // Add primary disk info
    if len(sysInfo.DiskInfo) > 0 {
        primaryDisk := sysInfo.DiskInfo[0]
        report.DiskTotal = primaryDisk.Total
        report.DiskUsed = primaryDisk.Used
        report.Metadata["disk_mount"] = primaryDisk.Mountpoint
        report.Metadata["disk_filesystem"] = primaryDisk.Filesystem
    }

    // Add metadata
    report.Metadata["collected_at"] = time.Now().Format(time.RFC3339)
    report.Metadata["hostname"] = sysInfo.Hostname
    report.Metadata["os_type"] = sysInfo.OSType
    report.Metadata["os_version"] = sysInfo.OSVersion
    report.Metadata["os_architecture"] = sysInfo.OSArchitecture

    // Report to server
    if err := apiClient.ReportSystemInfo(cfg.AgentID, report); err != nil {
        return fmt.Errorf("failed to report system info: %w", err)
    }

    return nil
}

Timing:

Runs hourly (line 407-408: const systemInfoUpdateInterval = 1 * time.Hour)
Triggered in main loop (lines 417-425)
Separate from scan operations

6. System Info Data Structures

File: /home/memory/Desktop/Projects/RedFlag/aggregator-agent/internal/system/info.go
Lines: 13-57

// SystemInfo contains detailed system information
type SystemInfo struct {
    Hostname       string            `json:"hostname"`
    OSType         string            `json:"os_type"`
    OSVersion      string            `json:"os_version"`
    OSArchitecture string            `json:"os_architecture"`
    AgentVersion   string            `json:"agent_version"`
    IPAddress      string            `json:"ip_address"`
    CPUInfo        CPUInfo           `json:"cpu_info"`
    MemoryInfo     MemoryInfo        `json:"memory_info"`
    DiskInfo       []DiskInfo        `json:"disk_info"`  // MULTIPLE DISKS!
    RunningProcesses int             `json:"running_processes"`
    Uptime         string            `json:"uptime"`
    RebootRequired bool              `json:"reboot_required"`
    RebootReason   string            `json:"reboot_reason"`
    Metadata       map[string]string `json:"metadata"`
}

// CPUInfo contains CPU information
type CPUInfo struct {
    ModelName string `json:"model_name"`
    Cores     int    `json:"cores"`
    Threads   int    `json:"threads"`
}

// MemoryInfo contains memory information
type MemoryInfo struct {
    Total       uint64  `json:"total"`
    Available   uint64  `json:"available"`
    Used        uint64  `json:"used"`
    UsedPercent float64 `json:"used_percent"`
}

// DiskInfo contains disk information for modular storage management
type DiskInfo struct {
    Mountpoint    string  `json:"mountpoint"`
    Total         uint64  `json:"total"`
    Available     uint64  `json:"available"`
    Used          uint64  `json:"used"`
    UsedPercent   float64 `json:"used_percent"`
    Filesystem    string  `json:"filesystem"`
    IsRoot        bool    `json:"is_root"`        // Primary system disk
    IsLargest     bool    `json:"is_largest"`     // Largest storage disk
    DiskType      string  `json:"disk_type"`      // SSD, HDD, NVMe, etc.
    Device        string  `json:"device"`         // Block device name
}

Important Notes:

Supports multiple disks (DiskInfo is a slice)
Each disk tracked separately (mount point, filesystem type, device)
Reports primary (IsRoot) and largest (IsLargest) disk separately
Well-structured for expansion

Summary

Monolithic: The orchestration function (handleScanUpdates) that combines all scanners
Modular: Individual scanner implementations and system info collection
Missing: Formal subsystem abstraction layer and lifecycle management

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