ROX-24273: PR comments

fleetshard/pkg/central/reconciler/gen/main.go

@@ -1,21 +1,24 @@
-// We do not install the tenant-resources using helm, so we don't have garbage collection when we delete the chart.
-// The main obstacle when performing garbage collection manually is that some resources might be optional (not rendered in all cases)
-// and we need to be able to identify them. The reconciler should be able to identify the resources that it should manage.
-
-// The purpose of this file is to
-// 1. Extract the apiVersions/kinds that are present in the tenant-resources chart
-// 2. Append to the list of apiVersion/kinds managed by the tenant-resources chart
-//    Resources removed from the chart will not be removed from the list. This is intentional.
-//    When rolling out a new version of the chart, the reconciler should be aware of resources
-//    managed by previous versions of the chart.
-// 3. The generated file is used by the reconciler to determine the resources that it should manage
-// 4. If the generated file is out of date, CI should fail
+// This program generates a list of GVKs used by the tenant-resources helm chart for enabling garbage collection.
+//
+// To enable garbage collection without this list, we would need to...
+// - Manually maintain a list of GVKs present in the chart, which would be error-prone.
+// - Or have the reconciler list all objects for all possible GVKs, which would be very expensive.
+// - Switch to the native helm client or the helm operator, which would require a lot of changes.
+//
+// This program automatically generates that list.
+//
+// Process:
+// - It extract the GVKs that are present in the tenant-resources chart manifests
+// - It extract the GVKs that are already declared in the generated file
+// - It combines the two lists
+// - It writes the combined list to the generated file
 
 package main
 
 import (
 	"fmt"
 	"io/fs"
+	"k8s.io/apimachinery/pkg/runtime/schema"
 	"os"
 	"path"
 	"path/filepath"
@@ -25,156 +28,205 @@ import (
 	"strings"
 )
 
+var (
+	reconcilerDir           = path.Join(path.Dir(getCurrentFile()), "..")
+	outFile                 = fmt.Sprintf("%s/zzz_managed_resources.go", reconcilerDir)
+	tenantResourcesChartDir = path.Join(path.Dir(getCurrentFile()), "../../charts/data/tenant-resources/templates")
+	gvkRegex                = regexp.MustCompile(`schema.GroupVersionKind{Group: "(.*)", Version: "(.*)", Kind: "(.*)"},`)
+)
+
+const (
+	apiVersionPrefix = "apiVersion: "
+	kindPrefix       = "kind: "
+)
+
 func main() {
-	fmt.Println("generating managed resources list for the tenant-resources chart")
 	if err := generate(); err != nil {
 		panic(err)
 	}
 }
 
+type resourceMap map[schema.GroupVersionKind]bool
+
+func generate() error {
+
+	// Holds a map of GVKs that will be in the output file
+	// The value `bool` indicates that the resource is present in the tenant-resources helm chart
+	// If false, this means that the resource is only present in the generated file (for GVKs removed from the chart)
+	// But the GVK is still needed for garbage collection.
+	seen := resourceMap{}
+
+	// Finding GVKs used in the tenant-resources chart
+	if err := findGVKsInChart(tenantResourcesChartDir, seen); err != nil {
+		return err
+	}
+
+	// Finding GVKs already declared in the generated file
+	if err := findGVKsInGeneratedFile(seen); err != nil {
+		return err
+	}
+
+	// Re-generating the file
+	if err := generateGVKsList(seen); err != nil {
+		return err
+	}
+
+	return nil
+}
+
 func getCurrentFile() string {
 	_, file, _, _ := runtime.Caller(0)
 	return file
 }
 
-func getChartDir() string {
-	return path.Join(path.Dir(getCurrentFile()), "../../charts/data/tenant-resources/templates")
+func generateGVKsList(seen resourceMap) error {
+	// Making sure resources are ordered (for deterministic output)
+	sorted := sortResourceKeys(seen)
+
+	builder := strings.Builder{}
+	builder.WriteString("// Code generated by fleetshard/pkg/central/reconciler/gen/main.go. DO NOT EDIT.\n")
+	builder.WriteString("package reconciler\n\n")
+	builder.WriteString("import (\n")
+	builder.WriteString("\t\"k8s.io/apimachinery/pkg/runtime/schema\"\n")
+	builder.WriteString(")\n\n")
+
+	builder.WriteString("// tenantChartResourceGVKs is a list of GroupVersionKind that... \n")
+	builder.WriteString("// - are present in the tenant-resources helm chart\n")
+	builder.WriteString("// - were present in a previous version of the chart. A comment will indicate that manual removal from the list is required.\n")
+
+	builder.WriteString("var tenantChartResourceGVKs = []schema.GroupVersionKind{\n")
+	for _, k := range sorted {
+		builder.WriteString(fmt.Sprintf("\tschema.GroupVersionKind{Group: %q, Version: %q, Kind: %q},", k.Group, k.Version, k.Kind))
+		stillInChart := seen[k]
+		if !stillInChart {
+			builder.WriteString(" // This resource was present in a previous version of the chart. Manual removal is required.")
+		}
+		builder.WriteString("\n")
+	}
+	builder.WriteString("}\n")
+
+	genFile, err := os.Create(outFile)
+	if err != nil {
+		return err
+	}
+	defer genFile.Close()
+
+	genFile.WriteString(builder.String())
+	return nil
 }
 
-func getReconcilerDir() string {
-	return path.Join(path.Dir(getCurrentFile()), "..")
+func sortResourceKeys(seen resourceMap) []schema.GroupVersionKind {
+	sorted := make([]schema.GroupVersionKind, 0, len(seen))
+	for k := range seen {
+		sorted = append(sorted, k)
+	}
+	sort.Slice(sorted, func(i, j int) bool {
+		left := sorted[i]
+		right := sorted[j]
+		return left.String() < right.String()
+	})
+	return sorted
 }
 
-func generate() error {
-	chartDir := getChartDir()
-	seen := map[[3]string]bool{}
+func findGVKsInGeneratedFile(seen resourceMap) error {
+	if _, err := os.Stat(outFile); err != nil {
+		if os.IsNotExist(err) {
+			return nil
+		}
+		return err
+	}
+
+	file, err := os.Open(outFile)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	fileBytes, err := os.ReadFile(outFile)
+	if err != nil {
+		return err
+	}
+
+	lines := strings.Split(string(fileBytes), "\n")
+
+	for _, line := range lines {
+		matches := gvkRegex.FindStringSubmatch(line)
+		if len(matches) != 4 {
+			continue
+		}
+		gvk := schema.GroupVersionKind{Group: matches[1], Version: matches[2], Kind: matches[3]}
+		isAlreadyPresent := seen[gvk]
+		seen[gvk] = isAlreadyPresent
+	}
+	return nil
+}
+
+func findGVKsInChart(chartDir string, seen resourceMap) error {
 	if err := filepath.WalkDir(chartDir, func(path string, d fs.DirEntry, err error) error {
 		if d.IsDir() {
 			return nil
 		}
+
 		ext := filepath.Ext(path)
 		if ext != ".yaml" && ext != ".yml" {
 			return nil
 		}
+
 		fileBytes, err := os.ReadFile(path)
 		if err != nil {
 			return err
 		}
 
-		fileStr := string(fileBytes)
-		lines := strings.Split(fileStr, "\n")
-		for i := 0; i < len(lines)-1; i++ {
-			line1 := lines[i]
-			line2 := lines[i+1]
-			if line1 > line2 {
-				line1, line2 = line2, line1
-			}
-
-			if !strings.HasPrefix(line1, "apiVersion: ") {
-				continue
-			}
-			if !strings.HasPrefix(line2, "kind: ") {
-				continue
-			}
-			apiVersion := strings.TrimSpace(strings.TrimPrefix(line1, "apiVersion: "))
-			kind := strings.TrimSpace(strings.TrimPrefix(line2, "kind: "))
-			apiVersionParts := strings.Split(apiVersion, "/")
-			if len(apiVersionParts) > 2 {
-				return fmt.Errorf("invalid apiVersion %s", apiVersion)
-			}
-			var group string
-			var version string
-
-			if len(apiVersionParts) == 2 {
-				group = apiVersionParts[0]
-				version = apiVersionParts[1]
-			} else {
-				version = apiVersionParts[0]
-			}
-
-			seen[[3]string{kind, group, version}] = true
+		if err := findGVKsInFile(fileBytes, seen); err != nil {
+			return err
 		}
+
 		return nil
 	}); err != nil {
 		return err
 	}
+	return nil
+}
 
-	outFile := fmt.Sprintf("%s/zzz_managed_resources.go", getReconcilerDir())
-
-	// retrieve existing declared resources
-	if _, err := os.Stat(outFile); err == nil {
-		// file exists
-		file, err := os.Open(outFile)
-		if err != nil {
-			return err
-		}
-		defer file.Close()
+func splitFileIntoResources(fileBytes []byte) []string {
+	fileStr := string(fileBytes)
+	return strings.Split(fileStr, "---")
+}
 
-		// read existing file
-		fileBytes, err := os.ReadFile(outFile)
-		if err != nil {
+func findGVKsInFile(fileBytes []byte, seen resourceMap) error {
+	resources := splitFileIntoResources(fileBytes)
+	for _, resource := range resources {
+		gvk, ok, err := findResourceGVK(resource)
+		if err != nil || !ok {
 			return err
 		}
-
-		fileStr := string(fileBytes)
-		lines := strings.Split(fileStr, "\n")
-		rgx := regexp.MustCompile(`schema.GroupVersionKind{Group: "(.*)", Version: "(.*)", Kind: "(.*)"},`)
-		for _, line := range lines {
-			matches := rgx.FindStringSubmatch(line)
-			if len(matches) != 4 {
-				continue
-			}
-			kind := matches[3]
-			group := matches[1]
-			version := matches[2]
-			fmt.Printf("found existing resource: %s/%s/%s\n", kind, group, version)
-			key := [3]string{kind, group, version}
-			seen[key] = seen[key]
-		}
-	}
-
-	sorted := make([][3]string, 0, len(seen))
-	for k := range seen {
-		sorted = append(sorted, k)
+		seen[gvk] = true
 	}
-	sort.Slice(sorted, func(i, j int) bool {
-		left := sorted[i]
-		right := sorted[j]
+	return nil
+}
 
-		if left[0] != right[0] {
-			return left[0] < right[0]
+func findResourceGVK(resource string) (schema.GroupVersionKind, bool, error) {
+	lines := strings.Split(resource, "\n")
+	apiVersion := ""
+	kind := ""
+	for i := 0; i < len(lines); i++ {
+		if strings.HasPrefix(lines[i], apiVersionPrefix) {
+			apiVersion = strings.TrimSpace(strings.TrimPrefix(lines[i], apiVersionPrefix))
+			continue
 		}
-		if left[1] != right[1] {
-			return left[1] < right[1]
-		}
-		return left[2] < right[2]
-	})
-
-	builder := strings.Builder{}
-	builder.WriteString("// Code generated by fleetshard/pkg/central/reconciler/gen/main.go. DO NOT EDIT.\n")
-	builder.WriteString("package reconciler\n\n")
-	builder.WriteString("import (\n")
-	builder.WriteString("\t\"k8s.io/apimachinery/pkg/runtime/schema\"\n")
-	builder.WriteString(")\n\n")
-
-	builder.WriteString("var tenantChartResourceGVKs = []schema.GroupVersionKind{\n")
-	for _, k := range sorted {
-		builder.WriteString(fmt.Sprintf("\tschema.GroupVersionKind{Group: %q, Version: %q, Kind: %q},", k[1], k[2], k[0]))
-		stillInChart := seen[k]
-		if !stillInChart {
-			builder.WriteString(" // This resource was present in a previous version of the chart. Manual removal is required.")
+		if strings.HasPrefix(lines[i], kindPrefix) {
+			kind = strings.TrimSpace(strings.TrimPrefix(lines[i], kindPrefix))
+			continue
 		}
-		builder.WriteString("\n")
 	}
-	builder.WriteString("}\n")
+	if len(apiVersion) == 0 || len(kind) == 0 {
+		return schema.GroupVersionKind{}, false, nil
+	}
 
-	genFile, err := os.Create(outFile)
+	groupVersion, err := schema.ParseGroupVersion(apiVersion)
 	if err != nil {
-		return err
+		return schema.GroupVersionKind{}, false, err
 	}
-	defer genFile.Close()
 
-	genFile.WriteString(builder.String())
-
-	return nil
+	return groupVersion.WithKind(kind), true, nil
 }