VPA: Add automated flag generator for all components

vertical-pod-autoscaler/hack/vpa-generate-flags.go

@@ -0,0 +1,257 @@
+/*
+Copyright 2024 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"io"
+	"log"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+	"text/template"
+	"time"
+)
+
+type flagInfo struct {
+	Name         string
+	DefaultValue string
+	Type         string
+	Description  string
+	SourceFile   string
+}
+
+type templateData struct {
+	Flags     []flagInfo
+	Timestamp string
+}
+
+var componentTemplates = map[string]string{
+	"recommender": `# What are the parameters to VPA recommender?
+This document is auto-generated from the flag definitions in the VPA recommender code.
+Last updated: {{ .Timestamp }}
+
+| Flag | Type | Default | Description |
+|------|------|---------|-------------|
+{{- range .Flags }}
+| --{{ .Name }} | {{ .Type }} | {{ .DefaultValue }} | {{ .Description }} |
+{{- end }}
+`,
+	"updater": `# What are the parameters to VPA updater?
+This document is auto-generated from the flag definitions in the VPA updater code.
+Last updated: {{ .Timestamp }}
+
+| Flag | Type | Default | Description |
+|------|------|---------|-------------|
+{{- range .Flags }}
+| --{{ .Name }} | {{ .Type }} | {{ .DefaultValue }} | {{ .Description }} |
+{{- end }}
+`,
+	"admission": `# What are the parameters to VPA admission controller?
+This document is auto-generated from the flag definitions in the VPA admission controller code.
+Last updated: {{ .Timestamp }}
+
+| Flag | Type | Default | Description |
+|------|------|---------|-------------|
+{{- range .Flags }}
+| --{{ .Name }} | {{ .Type }} | {{ .DefaultValue }} | {{ .Description }} |
+{{- end }}
+`,
+}
+
+func main() {
+	if len(os.Args) != 3 {
+		fmt.Println("Generates markdown documentation for VPA recommender flags.")
+		fmt.Println("usage: vpa-recommender-generate-flags <source-dir> <output-file>")
+		fmt.Println("  <source-dir>  - Path to the directory containing the Go source files")
+		fmt.Println("  <output-file> - Path to the output markdown file")
+		os.Exit(1)
+	}
+
+	sourceDir := os.Args[1]
+	outputFile := os.Args[2]
+
+	flags, err := collectFlags(sourceDir)
+	if err != nil {
+		log.Fatalf("Error collecting flags: %v", err)
+	}
+
+	sort.Slice(flags, func(i, j int) bool {
+		return flags[i].Name < flags[j].Name
+	})
+
+	err = generateDocs(flags, outputFile)
+	if err != nil {
+		log.Fatalf("Error generating documentation: %v", err)
+	}
+
+	fmt.Println("Successfully generated documentation in", outputFile)
+}
+
+func extractFlagFromCall(call *ast.CallExpr, sourcePath string) *flagInfo {
+	if len(call.Args) < 3 {
+		return nil
+	}
+
+	// Extract flag name
+	nameArg, ok := call.Args[0].(*ast.BasicLit)
+	if !ok {
+		return nil
+	}
+	name := strings.Trim(nameArg.Value, "\"")
+
+	// Extract default value
+	var defaultValue string
+	switch v := call.Args[1].(type) {
+	case *ast.BasicLit:
+		defaultValue = strings.Trim(v.Value, "\"")
+	case *ast.Ident:
+		defaultValue = v.Name
+	default:
+		defaultValue = fmt.Sprintf("%v", v)
+	}
+
+	// Extract description
+	descArg, ok := call.Args[2].(*ast.BasicLit)
+	if !ok {
+		return nil
+	}
+	description := strings.Trim(descArg.Value, "\"")
+
+	return &flagInfo{
+		Name:         name,
+		DefaultValue: defaultValue,
+		Type:         call.Fun.(*ast.SelectorExpr).Sel.Name,
+		Description:  description,
+		SourceFile:   sourcePath,
+	}
+}
+
+func collectFlags(sourceDir string) ([]flagInfo, error) {
+	var flags []flagInfo
+
+	err := filepath.Walk(sourceDir, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+
+		// Skip non-Go files
+		if !strings.HasSuffix(path, ".go") || info.IsDir() {
+			return nil
+		}
+
+		fset := token.NewFileSet()
+		file, err := parser.ParseFile(fset, path, nil, parser.ParseComments)
+
+		if err != nil {
+			return fmt.Errorf("error parsing file %s: %v", path, err)
+		}
+
+		fileFlags := extractFlags(file, getRelativePath(sourceDir, path))
+		flags = append(flags, fileFlags...)
+
+		return nil
+	})
+
+	return flags, err
+}
+
+func extractFlags(file *ast.File, sourcePath string) []flagInfo {
+	var flags []flagInfo
+
+	ast.Inspect(file, func(n ast.Node) bool {
+		// Look for flag.String(), flag.Bool(), flag.Float64(), etc.
+		if call, ok := n.(*ast.CallExpr); ok {
+			if sel, ok := call.Fun.(*ast.SelectorExpr); ok {
+				if ident, ok := sel.X.(*ast.Ident); ok {
+					if ident.Name == "flag" {
+						if flag := extractFlagFromCall(call, sourcePath); flag != nil {
+							flags = append(flags, *flag)
+						}
+					}
+				}
+			}
+		}
+		return true
+	})
+
+	return flags
+}
+
+func generateDocs(flags []flagInfo, outputFile string) error {
+	component := determineComponent(outputFile)
+	markdownTemplate, ok := componentTemplates[component]
+	if !ok {
+		return fmt.Errorf("couldn't find template for %s ", component)
+	}
+	tmpl, err := template.New("flags").Parse(markdownTemplate)
+	if err != nil {
+		return fmt.Errorf("error parsing template: %v", err)
+	}
+
+	data := templateData{
+		Flags:     flags,
+		Timestamp: time.Now().UTC().Format("2006-01-02 15:04:05 UTC"),
+	}
+
+	var buf bytes.Buffer
+	if err := tmpl.Execute(&buf, data); err != nil {
+		return fmt.Errorf("error executing template: %v", err)
+	}
+
+	f, err := os.Create(outputFile)
+	if err != nil {
+		return fmt.Errorf("error creating output file: %v", err)
+	}
+	defer f.Close()
+
+	_, err = io.Copy(f, &buf)
+	return err
+}
+
+func getRelativePath(baseDir, fullPath string) string {
+	rel, err := filepath.Rel(baseDir, fullPath)
+	if err != nil {
+		return fullPath
+	}
+	return rel
+}
+
+// We determine the component by the path of the output file.
+// if the path contains "recommender", we generate recommender flags.
+// if the path contains "updater", we generate updater flags.
+// if the path contains "admission", we generate admission flags.
+// Otherwise, we generate recommender flags.
+
+func determineComponent(outputPath string) string {
+	if strings.Contains(outputPath, "updater") {
+		return "updater"
+	}
+	if strings.Contains(outputPath, "admission") {
+		return "admission"
+	}
+	if strings.Contains(outputPath, "recommender") {
+		return "recommender"
+	}
+	fmt.Println("Couldn't find component. default is recommender")
+	return "recommender"
+}

vertical-pod-autoscaler/pkg/admission-controller/Makefile

@@ -88,3 +88,7 @@ format:
 	test -z "$$(find . -path ./vendor -prune -type f -o -name '*.go' -exec gofmt -s -w {} + | tee /dev/stderr)"
 
 .PHONY: all build test-unit clean format release
+
+.PHONY: admission-flags
+admission-flags:
+	go run ../../hack/vpa-generate-flags.go . ../../docs/vpa-admission-flags.md

vertical-pod-autoscaler/pkg/recommender/Makefile

@@ -90,3 +90,7 @@ format:
 	test -z "$$(find . -path ./vendor -prune -type f -o -name '*.go' -exec gofmt -s -w {} + | tee /dev/stderr)"
 
 .PHONY: all build test-unit clean format release
+
+.PHONY: recommender-flags
+recommender-flags:
+	go run ../../hack/vpa-generate-flags.go . ../../docs/vpa-recommender-flags.md

vertical-pod-autoscaler/pkg/updater/Makefile

@@ -88,3 +88,7 @@ format:
 	test -z "$$(find . -path ./vendor -prune -type f -o -name '*.go' -exec gofmt -s -w {} + | tee /dev/stderr)"
 
 .PHONY: all build test-unit clean format release
+
+.PHONY: updater-flags
+updater-flags:
+	go run ../../hack/vpa-generate-flags.go . ../../docs/vpa-updater-flags.md