Introduce ack-generate webhooks subcommand

This patch brings in a new sub command that can be used to generate
webhook functions. For now it can only generate conversion webhook
functions, but it can be used to generate defaulting and validating
functions.

This patch also introduces a new function to load existing ack-generate
metadata for a given api version.

Author: a-hilaly

cmd/ack-generate/command/webhook.go

@@ -0,0 +1,128 @@
+// Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License"). You may
+// not use this file except in compliance with the License. A copy of the
+// License is located at
+//
+//     http://aws.amazon.com/apache2.0/
+//
+// or in the "license" file accompanying this file. This file 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 command
+
+import (
+	"fmt"
+	"io/ioutil"
+	"path/filepath"
+	"strings"
+
+	"github.com/spf13/cobra"
+
+	"github.com/aws-controllers-k8s/code-generator/pkg/generate/ack"
+	ackgenerate "github.com/aws-controllers-k8s/code-generator/pkg/generate/ack"
+	"github.com/aws-controllers-k8s/code-generator/pkg/model/multiversion"
+)
+
+var (
+	optHubVersion              string
+	optDeprecatedVersions      []string
+	optEnableConversionWebhook bool
+)
+
+var webhooksCmd = &cobra.Command{
+	Use:   "webhooks <service>",
+	Short: "Generates Go files containing ",
+	RunE:  generateWebhooks,
+}
+
+func init() {
+	webhooksCmd.PersistentFlags().StringVar(
+		&optHubVersion, "hub-version", "", "the hub version for conversion webhooks",
+	)
+	webhooksCmd.PersistentFlags().BoolVar(
+		&optEnableConversionWebhook, "enable-conversion-webhooks", false, "enable conversion webhooks generation",
+	)
+	rootCmd.AddCommand(webhooksCmd)
+}
+
+// generateWebhooks generates the Go files for conversion, defaulting and validating webhooks.
+func generateWebhooks(cmd *cobra.Command, args []string) error {
+	if len(args) != 1 {
+		return fmt.Errorf("please specify the service alias for the AWS service API to generate")
+	}
+	svcAlias := strings.ToLower(args[0])
+	if optOutputPath == "" {
+		optOutputPath = filepath.Join(optServicesDir, svcAlias)
+	}
+
+	apisVersionPath = filepath.Join(optOutputPath, "apis")
+	files, err := ioutil.ReadDir(apisVersionPath)
+	if err != nil {
+		return err
+	}
+
+	apisInfos := map[string]multiversion.APIInfo{}
+	for _, f := range files {
+		metadata, err := ack.LoadGenerationMetadata(apisVersionPath, f.Name())
+		if err != nil {
+			return err
+		}
+		apisInfos[f.Name()] = multiversion.APIInfo{
+			// Setting the status to unknown for now.
+			// TODO(a-hilaly) read status from ack-generate-metadata.yaml
+			Status:              multiversion.APIStatusUnknown,
+			AWSSDKVersion:       metadata.AWSSDKGoVersion,
+			GeneratorConfigPath: filepath.Join(apisVersionPath, f.Name(), metadata.GeneratorConfigInfo.OriginalFileName),
+		}
+	}
+
+	if optHubVersion == "" {
+		latestAPIVersion, err := getLatestAPIVersion()
+		if err != nil {
+			return err
+		}
+		optHubVersion = latestAPIVersion
+	}
+
+	mgr, err := multiversion.NewAPIVersionManager(
+		optCacheDir,
+		svcAlias,
+		optHubVersion,
+		apisInfos,
+		ack.DefaultConfig,
+	)
+	if err != nil {
+		return err
+	}
+
+	if optEnableConversionWebhook {
+		ts, err := ackgenerate.ConversionWebhooks(mgr, optTemplateDirs)
+		if err != nil {
+			return err
+		}
+
+		if err = ts.Execute(); err != nil {
+			return err
+		}
+
+		for path, contents := range ts.Executed() {
+			if optDryRun {
+				fmt.Printf("============================= %s ======================================\n", path)
+				fmt.Println(strings.TrimSpace(contents.String()))
+				continue
+			}
+			outPath := filepath.Join(optOutputPath, path)
+			outDir := filepath.Dir(outPath)
+			if _, err := ensureDir(outDir); err != nil {
+				return err
+			}
+			if err = ioutil.WriteFile(outPath, contents.Bytes(), 0666); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}

pkg/generate/ack/output.go

@@ -145,6 +145,23 @@ func CreateGenerationMetadata(
 	return nil
 }
 
+// LoadGenerationMetadata read the generation metadata for a given api version and
+// apis path.
+func LoadGenerationMetadata(apisPath, apiVersion string) (*GenerationMetadata, error) {
+	filePath := filepath.Join(apisPath, apiVersion, outputFileName)
+	b, err := ioutil.ReadFile(filePath)
+	if err != nil {
+		return nil, err
+	}
+
+	var generationMetadata GenerationMetadata
+	err = yaml.Unmarshal(b, &generationMetadata)
+	if err != nil {
+		return nil, err
+	}
+	return &generationMetadata, nil
+}
+
 // hashDirectoryContent returns the sha1 checksum of a given directory. It will walk
 // the file tree of a directory and combine and the file contents before hashing it.
 func hashDirectoryContent(directory string) (string, error) {

pkg/generate/ack/webhook.go

@@ -0,0 +1,124 @@
+// Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License"). You may
+// not use this file except in compliance with the License. A copy of the
+// License is located at
+//
+//     http://aws.amazon.com/apache2.0/
+//
+// or in the "license" file accompanying this file. This file 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 ack
+
+import (
+	"fmt"
+	ttpl "text/template"
+
+	"github.com/aws-controllers-k8s/code-generator/pkg/generate/code"
+	"github.com/aws-controllers-k8s/code-generator/pkg/generate/templateset"
+	ackmodel "github.com/aws-controllers-k8s/code-generator/pkg/model"
+	"github.com/aws-controllers-k8s/code-generator/pkg/model/multiversion"
+)
+
+var (
+	webhooksIncludePaths = []string{
+		"boilerplate.go.tpl",
+		"apis/webhooks/conversion.go.tpl",
+	}
+	webhookCopyPaths = []string{}
+	webhooksFuncMap  = ttpl.FuncMap{
+		"GoCodeConvert": func(
+			src *ackmodel.CRD,
+			dst *ackmodel.CRD,
+			convertingToHub bool,
+			hubImportPath string,
+			sourceVarName string,
+			targetVarName string,
+			indentLevel int,
+		) string {
+			return code.Convert(src, dst, convertingToHub, hubImportPath, sourceVarName, targetVarName, indentLevel)
+		},
+	}
+)
+
+// ConversionWebhooks returns a pointer to a TemplateSet containing all the templates
+// for generating conversion webhooks.
+func ConversionWebhooks(
+	mgr *multiversion.APIVersionManager,
+	templateBasePaths []string,
+) (*templateset.TemplateSet, error) {
+	ts := templateset.New(
+		templateBasePaths,
+		webhooksIncludePaths,
+		webhookCopyPaths,
+		webhooksFuncMap,
+	)
+	hubVersion := mgr.GetHubVersion()
+	hubModel, err := mgr.GetModel(hubVersion)
+	if err != nil {
+		return nil, err
+	}
+
+	hubMetaVars := hubModel.MetaVars()
+	hubCRDs, err := hubModel.GetCRDs()
+	if err != nil {
+		return nil, err
+	}
+
+	for _, crd := range hubCRDs {
+		convertVars := conversionVars{
+			MetaVars:  hubMetaVars,
+			SourceCRD: crd,
+			IsHub:     true,
+		}
+		// Add the hub version template
+		target := fmt.Sprintf("apis/%s/%s_conversion.go", hubVersion, crd.Names.Snake)
+		if err = ts.Add(target, "apis/webhooks/conversion.go.tpl", convertVars); err != nil {
+			return nil, err
+		}
+	}
+
+	// Add spoke version templates
+	for _, spokeVersion := range mgr.GetSpokeVersions() {
+		model, err := mgr.GetModel(spokeVersion)
+		if err != nil {
+			return nil, err
+		}
+
+		metaVars := model.MetaVars()
+		crds, err := model.GetCRDs()
+		if err != nil {
+			return nil, err
+		}
+
+		for i, crd := range crds {
+			convertVars := conversionVars{
+				MetaVars:   metaVars,
+				SourceCRD:  crd,
+				DestCRD:    hubCRDs[i],
+				IsHub:      false,
+				HubVersion: hubVersion,
+			}
+
+			target := fmt.Sprintf("apis/%s/%s_conversion.go", spokeVersion, crd.Names.Snake)
+			if err = ts.Add(target, "apis/webhooks/conversion.go.tpl", convertVars); err != nil {
+				return nil, err
+			}
+		}
+	}
+
+	return ts, nil
+}
+
+// conversionVars contains template variables for templates that output
+// Go conversion functions.
+type conversionVars struct {
+	templateset.MetaVars
+	SourceCRD  *ackmodel.CRD
+	DestCRD    *ackmodel.CRD
+	HubVersion string
+	IsHub      bool
+}

templates/apis/webhooks/conversion.go.tpl

@@ -0,0 +1,62 @@
+{{- template "boilerplate" }}
+
+{{ $hubImportAlias := .HubVersion }}
+package {{ .APIVersion }}
+
+import (
+    "encoding/json"
+    "fmt"
+
+    ctrlrtconversion "sigs.k8s.io/controller-runtime/pkg/conversion"
+{{- if not .IsHub }}
+    ctrlrt "sigs.k8s.io/controller-runtime"
+    ackrtwh "github.com/aws-controllers-k8s/runtime/pkg/webhook"
+
+    {{ $hubImportAlias }} "github.com/aws-controllers-k8s/{{ .ServiceIDClean }}-controller/apis/{{ .HubVersion }}"
+{{- end }}
+)
+
+var (
+    _ = fmt.Printf
+    _ = json.Marshal
+)
+
+{{- if .IsHub }}
+// Assert hub interface implementation {{ .SourceCRD.Names.Camel }}
+var _ ctrlrtconversion.Hub = &{{ .SourceCRD.Names.Camel }}{}
+
+// Hub marks this type as conversion hub.
+func (*{{ .SourceCRD.Kind }}) Hub() {}
+{{ else }}
+
+func init() {
+    webhook := ackrtwh.New(
+        "conversion",
+        "{{ .SourceCRD.Names.Camel }}",
+        "{{ .APIVersion }}",
+		func(mgr ctrlrt.Manager) error {
+			return ctrlrt.NewWebhookManagedBy(mgr).
+				For(&{{ .SourceCRD.Names.Camel }}{}).
+				Complete()
+		},
+    )
+    if err := ackrtwh.RegisterWebhook(webhook); err != nil {
+        msg := fmt.Sprintf("cannot register webhook: %v", err)
+        panic(msg)
+    }
+}
+
+// Assert convertible interface implementation {{ .SourceCRD.Names.Camel }}
+var _ ctrlrtconversion.Convertible = &{{ .SourceCRD.Names.Camel }}{}
+
+// ConvertTo converts this {{ .SourceCRD.Kind }} to the Hub version ({{ .HubVersion }}).
+func (src *{{ .SourceCRD.Kind }}) ConvertTo(dstRaw ctrlrtconversion.Hub) error {
+{{- GoCodeConvert .SourceCRD .DestCRD true $hubImportAlias "src" "dstRaw" 1}}
+}
+
+// ConvertFrom converts the Hub version ({{ .HubVersion }}) to this {{ .SourceCRD.Kind }}.
+func (dst *{{ .SourceCRD.Kind }}) ConvertFrom(srcRaw ctrlrtconversion.Hub) error {
+{{- GoCodeConvert .SourceCRD .DestCRD false $hubImportAlias "dst" "srcRaw" 1}}
+}
+
+{{- end }}