feat(datagen): add ApplicationIdentity with per-role app allocation

internal/datagen/applications.go

@@ -1,5 +1,7 @@
 package datagen
 
+import "math/rand"
+
 // ApplicationIdentity represents installed software on a system.
 type ApplicationIdentity struct {
 	Name        string // "Microsoft SQL Server 2019"
@@ -9,3 +11,100 @@ type ApplicationIdentity struct {
 	InstallDate string // "2024-06-15"
 	SystemRef   string // back-reference: hostname of owning system
 }
+
+// appTemplate defines an application template.
+type appTemplate struct {
+	name        string
+	version     string
+	vendor      string
+	installPath string
+}
+
+var windowsServerApps = []appTemplate{
+	{"Internet Information Services", "10.0.20348", "Microsoft Corporation", `C:\Windows\System32\inetsrv`},
+	{"Microsoft SQL Server 2019", "15.0.4322.2", "Microsoft Corporation", `C:\Program Files\Microsoft SQL Server`},
+	{".NET Runtime 8.0", "8.0.1", "Microsoft Corporation", `C:\Program Files\dotnet`},
+	{"Microsoft Exchange Server 2019", "15.2.1118.40", "Microsoft Corporation", `C:\Program Files\Microsoft\Exchange Server`},
+	{"Microsoft SharePoint Server 2019", "16.0.10396.20000", "Microsoft Corporation", `C:\Program Files\Microsoft Office Servers`},
+	{"Windows Server Backup", "10.0.20348", "Microsoft Corporation", `C:\Windows\System32`},
+	{"Microsoft Visual C++ 2019 Redistributable", "14.29.30133", "Microsoft Corporation", `C:\Program Files\Microsoft Visual Studio`},
+}
+
+var linuxServerApps = []appTemplate{
+	{"nginx", "1.24.0", "Nginx Inc.", "/usr/sbin/nginx"},
+	{"Apache HTTP Server", "2.4.58", "Apache Software Foundation", "/usr/sbin/apache2"},
+	{"PostgreSQL", "16.1", "PostgreSQL Global Development Group", "/usr/lib/postgresql/16"},
+	{"MySQL", "8.0.35", "Oracle Corporation", "/usr/sbin/mysqld"},
+	{"Docker Engine", "24.0.7", "Docker Inc.", "/usr/bin/docker"},
+	{"OpenJDK Runtime Environment", "17.0.9", "Eclipse Adoptium", "/usr/lib/jvm/java-17-openjdk"},
+	{"Node.js", "20.10.0", "OpenJS Foundation", "/usr/bin/node"},
+	{"Redis", "7.2.3", "Redis Ltd.", "/usr/bin/redis-server"},
+}
+
+var workstationApps = []appTemplate{
+	{"Microsoft Office 365 ProPlus", "16.0.17126.20132", "Microsoft Corporation", `C:\Program Files\Microsoft Office`},
+	{"Google Chrome", "120.0.6099.130", "Google LLC", `C:\Program Files\Google\Chrome`},
+	{"Mozilla Firefox", "121.0", "Mozilla Foundation", `C:\Program Files\Mozilla Firefox`},
+	{"Visual Studio Code", "1.85.1", "Microsoft Corporation", `C:\Users\AppData\Local\Programs\Microsoft VS Code`},
+	{"Slack", "4.35.126", "Slack Technologies", `C:\Users\AppData\Local\slack`},
+	{"Microsoft Teams", "1.6.00.36062", "Microsoft Corporation", `C:\Users\AppData\Local\Microsoft\Teams`},
+	{"Zoom Workplace", "5.17.0", "Zoom Video Communications", `C:\Program Files\Zoom`},
+	{"Adobe Acrobat Reader", "23.008.20470", "Adobe Inc.", `C:\Program Files\Adobe\Acrobat Reader DC`},
+}
+
+var dcApps = []appTemplate{
+	{"Active Directory Domain Services", "10.0.20348", "Microsoft Corporation", `C:\Windows\System32`},
+	{"Active Directory Certificate Services", "10.0.20348", "Microsoft Corporation", `C:\Windows\System32\certsrv`},
+	{"DNS Server", "10.0.20348", "Microsoft Corporation", `C:\Windows\System32\dns.exe`},
+	{"DHCP Server", "10.0.20348", "Microsoft Corporation", `C:\Windows\System32`},
+	{"Remote Server Administration Tools", "10.0.20348", "Microsoft Corporation", `C:\Windows\System32`},
+	{"Group Policy Management Console", "10.0.20348", "Microsoft Corporation", `C:\Windows\System32`},
+}
+
+// installDates provides deterministic install date strings.
+var installDates = NewPool(
+	"2024-01-15", "2024-02-20", "2024-03-10", "2024-04-05",
+	"2024-05-18", "2024-06-22", "2024-07-30", "2024-08-14",
+	"2024-09-01", "2024-10-12", "2024-11-25", "2024-12-03",
+)
+
+// GenerateApplicationsForSystem returns applications appropriate for the given OS and role.
+func GenerateApplicationsForSystem(r *rand.Rand, os OSType, role SystemRole, hostname string) []*ApplicationIdentity {
+	var templates []appTemplate
+
+	switch {
+	case role == RoleDC:
+		templates = dcApps
+	case os == OSWindows && role == RoleServer:
+		templates = windowsServerApps
+	case os == OSLinux && (role == RoleServer || role == RoleRouter):
+		templates = linuxServerApps
+	default:
+		templates = workstationApps
+	}
+
+	// Pick a random subset (at least 2, up to all)
+	count := len(templates)
+	if count > 3 {
+		count = 2 + r.Intn(count-1) // #nosec G404
+		if count > len(templates) {
+			count = len(templates)
+		}
+	}
+
+	indices := r.Perm(len(templates))
+	apps := make([]*ApplicationIdentity, count)
+	for i := 0; i < count; i++ {
+		tmpl := templates[indices[i]]
+		apps[i] = &ApplicationIdentity{
+			Name:        tmpl.name,
+			Version:     tmpl.version,
+			Vendor:      tmpl.vendor,
+			InstallPath: tmpl.installPath,
+			InstallDate: installDates.Random(r),
+			SystemRef:   hostname,
+		}
+	}
+
+	return apps
+}

internal/datagen/applications_test.go

@@ -0,0 +1,67 @@
+package datagen
+
+import (
+	"math/rand"
+	"testing"
+)
+
+func TestGenerateApplicationsForSystem(t *testing.T) {
+	r := rand.New(rand.NewSource(42))
+
+	t.Run("windows server apps", func(t *testing.T) {
+		apps := GenerateApplicationsForSystem(r, OSWindows, RoleServer, "SRV01")
+		if len(apps) < 2 {
+			t.Errorf("expected at least 2 apps, got %d", len(apps))
+		}
+		for _, a := range apps {
+			if a.SystemRef != "SRV01" {
+				t.Errorf("expected SystemRef 'SRV01', got %q", a.SystemRef)
+			}
+			if a.Name == "" {
+				t.Error("app Name should not be empty")
+			}
+			if a.Version == "" {
+				t.Error("app Version should not be empty")
+			}
+			if a.Vendor == "" {
+				t.Error("app Vendor should not be empty")
+			}
+		}
+	})
+
+	t.Run("linux server apps", func(t *testing.T) {
+		apps := GenerateApplicationsForSystem(r, OSLinux, RoleServer, "srv01")
+		if len(apps) < 2 {
+			t.Errorf("expected at least 2 apps, got %d", len(apps))
+		}
+	})
+
+	t.Run("DC apps", func(t *testing.T) {
+		apps := GenerateApplicationsForSystem(r, OSWindows, RoleDC, "DC01")
+		if len(apps) < 2 {
+			t.Errorf("expected at least 2 apps, got %d", len(apps))
+		}
+	})
+
+	t.Run("workstation apps", func(t *testing.T) {
+		apps := GenerateApplicationsForSystem(r, OSWindows, RoleWorkstation, "WS01")
+		if len(apps) < 2 {
+			t.Errorf("expected at least 2 apps, got %d", len(apps))
+		}
+	})
+
+	t.Run("deterministic", func(t *testing.T) {
+		r1 := rand.New(rand.NewSource(99))
+		r2 := rand.New(rand.NewSource(99))
+		a1 := GenerateApplicationsForSystem(r1, OSWindows, RoleServer, "T")
+		a2 := GenerateApplicationsForSystem(r2, OSWindows, RoleServer, "T")
+		if len(a1) != len(a2) {
+			t.Fatalf("different lengths: %d vs %d", len(a1), len(a2))
+		}
+		for i := range a1 {
+			if a1[i].Name != a2[i].Name {
+				t.Errorf("app[%d]: %q vs %q", i, a1[i].Name, a2[i].Name)
+			}
+		}
+	})
+}