Improvements to conversions generator.

cmd/kube-conversion/conversion.go

@@ -20,7 +20,6 @@ import (
 	"io"
 	"os"
 	"runtime"
-	"strings"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 	_ "github.com/GoogleCloudPlatform/kubernetes/pkg/api/v1beta1"
@@ -33,39 +32,51 @@ import (
 )
 
 var (
-	outputDest = flag.StringP("output", "o", "-", "Output destination; '-' means stdout")
-	versions   = flag.StringP("versions", "v", "v1beta3", "Comma separated list of versions for conversion.")
+	functionDest = flag.StringP("funcDest", "f", "-", "Output for conversion functions; '-' means stdout")
+	namesDest    = flag.StringP("nameDest", "n", "-", "Output for function names; '-' means stdout")
+	version      = flag.StringP("version", "v", "v1beta3", "Version for conversion.")
 )
 
 func main() {
 	runtime.GOMAXPROCS(runtime.NumCPU())
 	flag.Parse()
 
-	var out io.Writer
-	if *outputDest == "-" {
-		out = os.Stdout
+	var funcOut io.Writer
+	if *functionDest == "-" {
+		funcOut = os.Stdout
 	} else {
-		file, err := os.Create(*outputDest)
+		file, err := os.Create(*functionDest)
 		if err != nil {
-			glog.Fatalf("Couldn't open %v: %v", *outputDest, err)
+			glog.Fatalf("Couldn't open %v: %v", *functionDest, err)
 		}
 		defer file.Close()
-		out = file
+		funcOut = file
 	}
-
-	versionsForConversion := strings.Split(*versions, ",")
-	for _, version := range versionsForConversion {
-		generator := conversion.NewGenerator(api.Scheme.Raw())
-		// TODO(wojtek-t): Change the overwrites to a flag.
-		generator.OverwritePackage(version, "")
-		generator.OverwritePackage("api", "newer")
-		for _, knownType := range api.Scheme.KnownTypes(version) {
-			if err := generator.GenerateConversionsForType(version, knownType); err != nil {
-				glog.Errorf("error while generating conversion functions for %v: %v", knownType, err)
-			}
+	var nameOut io.Writer
+	if *namesDest == "-" {
+		nameOut = os.Stdout
+	} else {
+		file, err := os.Create(*namesDest)
+		if err != nil {
+			glog.Fatalf("Couldn't open %v: %v", *functionDest, err)
 		}
-		if err := generator.WriteConversionFunctions(out); err != nil {
-			glog.Fatalf("Error while writing conversion functions: %v", err)
+		defer file.Close()
+		nameOut = file
+	}
+
+	generator := conversion.NewGenerator(api.Scheme.Raw())
+	// TODO(wojtek-t): Change the overwrites to a flag.
+	generator.OverwritePackage(*version, "")
+	generator.OverwritePackage("api", "newer")
+	for _, knownType := range api.Scheme.KnownTypes(*version) {
+		if err := generator.GenerateConversionsForType(*version, knownType); err != nil {
+			glog.Errorf("error while generating conversion functions for %v: %v", knownType, err)
 		}
 	}
+	if err := generator.WriteConversionFunctions(funcOut); err != nil {
+		glog.Fatalf("Error while writing conversion functions: %v", err)
+	}
+	if err := generator.WriteConversionFunctionNames(nameOut); err != nil {
+		glog.Fatalf("Error while writing conversion functions: %v", err)
+	}
 }

docs/devel/api_changes.md

@@ -222,9 +222,24 @@ types, structural change in particular - you must add some logic to convert
 versioned APIs to and from the internal representation.  If you see errors from
 the `serialization_test`, it may indicate the need for explicit conversions.
 
+Performance of conversions very heavily influence performance of apiserver.
+Thus, we are auto-generating conversion functions that are much more efficient
+than the generic ones (which are based on reflections and thus are highly
+inefficient).
+
 The conversion code resides with each versioned API -
-`pkg/api/<version>/conversion.go`.  Unsurprisingly, this also requires you to
-add tests to `pkg/api/<version>/conversion_test.go`.
+`pkg/api/<version>/conversion.go`.  To regenerate conversion functions:
+   - run
+```
+   $ go run cmd/kube-conversion/conversion.go -v <version> -f <file1.txt> -n <file2.txt>
+```
+   - replace all conversion functions (convert\* functions) in the above file
+     with the contents of \<file1.txt\>
+   - replace arguments of `newer.Scheme.AddGeneratedConversionFuncs`
+     with the contents of \<file2.txt\>
+
+Unsurprisingly, this also requires you to add tests to
+`pkg/api/<version>/conversion_test.go`.
 
 ## Update the fuzzer
 

pkg/conversion/generator.go

@@ -27,6 +27,7 @@ import (
 type Generator interface {
 	GenerateConversionsForType(version string, reflection reflect.Type) error
 	WriteConversionFunctions(w io.Writer) error
+	WriteConversionFunctionNames(w io.Writer) error
 	OverwritePackage(pkg, overwrite string)
 }
 
@@ -177,7 +178,7 @@ func (g *generator) WriteConversionFunctions(w io.Writer) error {
 	}
 	sort.Sort(byName(keys))
 
-	indent := 2
+	indent := 0
 	for _, inType := range keys {
 		outType := g.convertibles[inType]
 		// All types in g.convertibles are structs.
@@ -194,12 +195,32 @@ func (g *generator) WriteConversionFunctions(w io.Writer) error {
 	return nil
 }
 
+func (g *generator) WriteConversionFunctionNames(w io.Writer) error {
+	// Write conversion function names alphabetically ordered.
+	var names []string
+	for inType, outType := range g.convertibles {
+		names = append(names, conversionFunctionName(inType, outType))
+		names = append(names, conversionFunctionName(outType, inType))
+	}
+	sort.Strings(names)
+
+	indent := 2
+	for _, name := range names {
+		if err := writeLine(w, indent, fmt.Sprintf("%s,\n", name)); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 func (g *generator) typeName(inType reflect.Type) string {
 	switch inType.Kind() {
 	case reflect.Map:
 		return fmt.Sprintf("map[%s]%s", g.typeName(inType.Key()), g.typeName(inType.Elem()))
 	case reflect.Slice:
 		return fmt.Sprintf("[]%s", g.typeName(inType.Elem()))
+	case reflect.Ptr:
+		return fmt.Sprintf("*%s", g.typeName(inType.Elem()))
 	default:
 		typeWithPkg := fmt.Sprintf("%s", inType)
 		slices := strings.Split(typeWithPkg, ".")
@@ -221,6 +242,22 @@ func (g *generator) typeName(inType reflect.Type) string {
 	}
 }
 
+func packageForName(inType reflect.Type) string {
+	if inType.PkgPath() == "" {
+		return ""
+	}
+	slices := strings.Split(inType.PkgPath(), "/")
+	return slices[len(slices)-1]
+}
+
+func conversionFunctionName(inType, outType reflect.Type) string {
+	funcNameFormat := "convert_%s_%s_To_%s_%s"
+	inPkg := packageForName(inType)
+	outPkg := packageForName(outType)
+	funcName := fmt.Sprintf(funcNameFormat, inPkg, inType.Name(), outPkg, outType.Name())
+	return funcName
+}
+
 func indentLine(w io.Writer, indent int) error {
 	indentation := ""
 	for i := 0; i < indent; i++ {
@@ -240,9 +277,9 @@ func writeLine(w io.Writer, indent int, line string) error {
 	return nil
 }
 
-func writeHeader(w io.Writer, inType, outType string, indent int) error {
-	format := "func(in *%s, out *%s, s conversion.Scope) error {\n"
-	stmt := fmt.Sprintf(format, inType, outType)
+func writeHeader(w io.Writer, name, inType, outType string, indent int) error {
+	format := "func %s(in *%s, out *%s, s conversion.Scope) error {\n"
+	stmt := fmt.Sprintf(format, name, inType, outType)
 	return writeLine(w, indent, stmt)
 }
 
@@ -250,7 +287,7 @@ func writeFooter(w io.Writer, indent int) error {
 	if err := writeLine(w, indent+1, "return nil\n"); err != nil {
 		return err
 	}
-	if err := writeLine(w, indent, "},\n"); err != nil {
+	if err := writeLine(w, indent, "}\n"); err != nil {
 		return err
 	}
 	return nil
@@ -336,13 +373,29 @@ func (g *generator) writeConversionForSlice(w io.Writer, inField, outField refle
 	if err := writeLine(w, indent+1, forStmt); err != nil {
 		return err
 	}
-	if inField.Type.Elem().AssignableTo(outField.Type.Elem()) {
-		assignFormat := "out.%s[i] = in.%s[i]\n"
-		assignStmt := fmt.Sprintf(assignFormat, outField.Name, inField.Name)
-		if err := writeLine(w, indent+2, assignStmt); err != nil {
-			return err
+	assigned := false
+	switch inField.Type.Elem().Kind() {
+	case reflect.Map, reflect.Ptr, reflect.Slice, reflect.Interface, reflect.Struct:
+		// Don't copy these via assignment/conversion!
+	default:
+		// This should handle all simple types.
+		if inField.Type.Elem().AssignableTo(outField.Type.Elem()) {
+			assignFormat := "out.%s[i] = in.%s[i]\n"
+			assignStmt := fmt.Sprintf(assignFormat, outField.Name, inField.Name)
+			if err := writeLine(w, indent+2, assignStmt); err != nil {
+				return err
+			}
+			assigned = true
+		} else if inField.Type.Elem().ConvertibleTo(outField.Type.Elem()) {
+			assignFormat := "out.%s[i] = %s(in.%s[i])\n"
+			assignStmt := fmt.Sprintf(assignFormat, outField.Name, g.typeName(outField.Type.Elem()), inField.Name)
+			if err := writeLine(w, indent+2, assignStmt); err != nil {
+				return err
+			}
+			assigned = true
 		}
-	} else {
+	}
+	if !assigned {
 		assignFormat := "if err := s.Convert(&in.%s[i], &out.%s[i], 0); err != nil {\n"
 		assignStmt := fmt.Sprintf(assignFormat, inField.Name, outField.Name)
 		if err := writeLine(w, indent+2, assignStmt); err != nil {
@@ -471,10 +524,6 @@ func (g *generator) writeConversionForStruct(w io.Writer, inType, outType reflec
 			continue
 		}
 
-		// TODO(wojtek-t): At some point we may consider named functions and call
-		// appropriate function here instead of using generic Convert method that
-		// will call the same method underneath after some additional operations.
-
 		assignFormat := "if err := s.Convert(&in.%s, &out.%s, 0); err != nil {\n"
 		assignStmt := fmt.Sprintf(assignFormat, inField.Name, outField.Name)
 		if err := writeLine(w, indent, assignStmt); err != nil {
@@ -491,7 +540,8 @@ func (g *generator) writeConversionForStruct(w io.Writer, inType, outType reflec
 }
 
 func (g *generator) writeConversionForType(w io.Writer, inType, outType reflect.Type, indent int) error {
-	if err := writeHeader(w, g.typeName(inType), g.typeName(outType), indent); err != nil {
+	funcName := conversionFunctionName(inType, outType)
+	if err := writeHeader(w, funcName, g.typeName(inType), g.typeName(outType), indent); err != nil {
 		return err
 	}
 	switch inType.Kind() {
@@ -505,6 +555,9 @@ func (g *generator) writeConversionForType(w io.Writer, inType, outType reflect.
 	if err := writeFooter(w, indent); err != nil {
 		return err
 	}
+	if err := writeLine(w, 0, "\n"); err != nil {
+		return err
+	}
 	return nil
 }