✨ Add kubebuilder alpha config-gen command to explore generating configuration with kustomize functions

doc.go

@@ -0,0 +1,21 @@
+/*
+Copyright 2020 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.
+*/
+
+//go:generate go run github.com/markbates/pkger/cmd/pkger
+
+// Package kubebuilder contains pkged files compiled into the
+// go binaries.
+package kubebuilder

go.mod

@@ -3,12 +3,21 @@ module sigs.k8s.io/kubebuilder/v3
 go 1.15
 
 require (
+	github.com/cloudflare/cfssl v1.5.0 // for `kubebuilder alpha config-gen`
 	github.com/gobuffalo/flect v0.2.2
+	// TODO: remove this in favor of embed once using 1.16
+	github.com/markbates/pkger v0.17.1 // for `kubebuilder alpha config-gen`
 	github.com/onsi/ginkgo v1.15.0
 	github.com/onsi/gomega v1.10.5
 	github.com/spf13/afero v1.2.2
-	github.com/spf13/cobra v0.0.7
+	github.com/spf13/cobra v1.1.1
 	github.com/spf13/pflag v1.0.5
 	golang.org/x/tools v0.0.0-20201224043029-2b0845dc783e
+	// for `kubebuilder alpha config-gen`
+	gopkg.in/yaml.v3 v3.0.0-20200615113413-eeeca48fe776 // indirect
+	k8s.io/apimachinery v0.20.2 // for `kubebuilder alpha config-gen`
+	k8s.io/utils v0.0.0-20210111153108-fddb29f9d009 // indirect
+	sigs.k8s.io/controller-tools v0.3.0 // for `kubebuilder alpha config-gen`
+	sigs.k8s.io/kustomize/kyaml v0.10.10 // for `kubebuilder alpha config-gen`
 	sigs.k8s.io/yaml v1.2.0
 )

pkg/cli/alpha.go

@@ -0,0 +1,52 @@
+/*
+Copyright 2021 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 cli
+
+import (
+	"strings"
+
+	"github.com/spf13/cobra"
+	configgen "sigs.k8s.io/kubebuilder/v3/pkg/cli/alpha/config-gen"
+)
+
+var alphaCommands = []*cobra.Command{
+	configgen.NewCommand(),
+}
+
+func (c *CLI) newAlphaCmd() *cobra.Command {
+	alpha := &cobra.Command{
+		Use:        "alpha",
+		SuggestFor: []string{"experimental"},
+		Short:      "Alpha kubebuilder subcommands",
+		Long: strings.TrimSpace(`
+Alpha kubebuilder commands are for unstable features.
+
+- Alpha commands are exploratory and may be removed without warning.
+- No backwards compatibility is provided for any alpha commands.
+ 		`),
+	}
+	for i := range alphaCommands {
+		alpha.AddCommand(alphaCommands[i])
+	}
+	return alpha
+}
+
+func (c *CLI) addAlphaCmd() {
+	if len(alphaCommands) > 0 {
+		c.cmd.AddCommand(c.newAlphaCmd())
+	}
+}

pkg/cli/alpha/config-gen/README.md

@@ -0,0 +1,41 @@
+# Config-gen
+
+`kubebuilder alpha config-gen` is a subcommand that generates configuration for kubebuilder projects as a configuration function.
+
+Supports:
+
+- Generating CRDs and RBAC from code
+- Generating webhook certificates for development
+- Selectively enabling / disabling components such as prometheus and webhooks
+  - See [types.go](apis/v1alpha1/types.go) for a list of components
+
+## Usage
+
+`config-gen` may be run as a standalone command or from kustomize as a transformer plugin.
+
+### Standalone command
+
+config-gen may be run as a standalone program on the commandline.
+
+See [examples/standalone](examples/standalone/README.md)
+
+### From kustomize
+
+config-gen may be run as a Kustomize plugin using kustomize.
+
+See [examples/kustomize](examples/kustomize/README.md)
+
+### Extending `config-gen`
+
+config-gen may be extended by composing additional functions on top of it.
+
+See examples of layering additional functions on:
+
+- [examples/basicextension](examples/basicextension/README.md)
+- [examples/advancedextension](examples/advancedextension/README.md)
+
+## `KubebuilderConfigGen`
+
+See [types.go](apis/v1alpha1/types.go) for KubebuilderConfigGen schema.
+
+See [testdata](apis/v1alpha1/testdata) for examples of configuration options.

pkg/cli/alpha/config-gen/cert-generation-filter.go

@@ -0,0 +1,164 @@
+/*
+Copyright 2021 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 configgen
+
+import (
+	"encoding/base64"
+	"fmt"
+
+	"github.com/cloudflare/cfssl/cli/genkey"
+	"github.com/cloudflare/cfssl/config"
+	"github.com/cloudflare/cfssl/csr"
+	"github.com/cloudflare/cfssl/helpers"
+	"github.com/cloudflare/cfssl/selfsign"
+	"sigs.k8s.io/kustomize/kyaml/fn/framework"
+	"sigs.k8s.io/kustomize/kyaml/kio"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+var _ kio.Filter = &CertFilter{}
+
+// CertFilter generates and injects certificates into webhook
+type CertFilter struct {
+	*KubebuilderConfigGen
+}
+
+// Filter implements kio.Filter
+func (c CertFilter) Filter(input []*yaml.RNode) ([]*yaml.RNode, error) {
+
+	if c.Spec.Webhooks.CertificateSource.Type != "dev" {
+		return input, nil
+	}
+	if err := c.generateCert(); err != nil {
+		return nil, err
+	}
+
+	s := &framework.Selector{
+		Kinds: []string{
+			"ValidatingWebhookConfiguration",
+			"MutatingWebhookConfiguration",
+		},
+	}
+	matches, err := s.GetMatches(&framework.ResourceList{Items: input})
+	if err != nil {
+		return nil, err
+	}
+	for i := range matches {
+		wh := matches[i].Field("webhooks")
+		if wh.IsNilOrEmpty() {
+			continue
+		}
+		err := wh.Value.VisitElements(func(node *yaml.RNode) error {
+			err := node.PipeE(yaml.LookupCreate(yaml.ScalarNode, "clientConfig", "caBundle"),
+				yaml.FieldSetter{StringValue: c.Status.CertCA})
+			if err != nil {
+				return err
+			}
+			err = node.PipeE(yaml.LookupCreate(yaml.ScalarNode, "clientConfig", "service", "namespace"),
+				yaml.FieldSetter{StringValue: c.Namespace})
+			if err != nil {
+				return err
+			}
+
+			return nil
+		})
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	s = &framework.Selector{
+		Filter: func(n *yaml.RNode) bool {
+			// Allow-list conversion webhooks
+			m, _ := n.GetMeta()
+			if m.Kind != "CustomResourceDefinition" {
+				return true
+			}
+			return c.Spec.Webhooks.Conversions[m.Name]
+		},
+	}
+	matches, err = s.GetMatches(&framework.ResourceList{Items: input})
+	if err != nil {
+		return nil, err
+	}
+	for i := range matches {
+		err := matches[i].PipeE(yaml.LookupCreate(yaml.ScalarNode, "spec", "conversion", "strategy"),
+			yaml.FieldSetter{StringValue: "Webhook"})
+		if err != nil {
+			return nil, err
+		}
+		err = matches[i].PipeE(yaml.LookupCreate(
+			yaml.ScalarNode, "spec", "conversion", "webhookClientConfig", "caBundle"),
+			yaml.FieldSetter{StringValue: c.Status.CertCA})
+		if err != nil {
+			return nil, err
+		}
+		err = matches[i].PipeE(yaml.LookupCreate(
+			yaml.ScalarNode, "spec", "conversion", "webhookClientConfig", "service", "name"),
+			yaml.FieldSetter{StringValue: "webhook-service"})
+		if err != nil {
+			return nil, err
+		}
+		err = matches[i].PipeE(yaml.LookupCreate(
+			yaml.ScalarNode, "spec", "conversion", "webhookClientConfig", "service", "namespace"),
+			yaml.FieldSetter{StringValue: c.Namespace})
+		if err != nil {
+			return nil, err
+		}
+
+		err = matches[i].PipeE(yaml.LookupCreate(
+			yaml.ScalarNode, "spec", "conversion", "webhookClientConfig", "service", "path"),
+			yaml.FieldSetter{StringValue: "/convert"})
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return input, nil
+}
+
+func (c CertFilter) generateCert() error {
+	var err error
+	var req = csr.New()
+	req.Hosts = []string{
+		fmt.Sprintf("webhook-service.%s.svc", c.Namespace),
+		fmt.Sprintf("webhook-service.%s.svc.cluster.local", c.Namespace),
+	}
+	req.CN = "kb-dev-controller-manager"
+
+	var key, csrPEM []byte
+	g := &csr.Generator{Validator: genkey.Validator}
+	csrPEM, key, err = g.ProcessRequest(req)
+	if err != nil {
+		return err
+	}
+	priv, err := helpers.ParsePrivateKeyPEM(key)
+	if err != nil {
+		return err
+	}
+
+	profile := config.DefaultConfig()
+	profile.Expiry = c.Spec.Webhooks.CertificateSource.DevCertificate.CertDuration
+	cert, err := selfsign.Sign(priv, csrPEM, profile)
+	if err != nil {
+		return err
+	}
+
+	c.Status.CertCA = base64.StdEncoding.EncodeToString(cert)
+	c.Status.CertKey = base64.StdEncoding.EncodeToString(key)
+	return nil
+}

pkg/cli/alpha/config-gen/cert-manager-patches.go

@@ -0,0 +1,39 @@
+/*
+Copyright 2021 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 configgen
+
+import (
+	"github.com/markbates/pkger"
+	"sigs.k8s.io/kustomize/kyaml/fn/framework"
+)
+
+// CertManagerPatchTemplate returns the PatchTemplate for cert-manager
+func CertManagerPatchTemplate(_ *KubebuilderConfigGen) framework.PT {
+	return framework.PT{
+		// keep casting -- required by pkger to find the directory
+		Dir: pkger.Dir("/pkg/cli/alpha/config-gen/templates/patches/cert-manager"),
+		Selector: func() *framework.Selector {
+			return &framework.Selector{
+				Kinds: []string{
+					"CustomResourceDefinition",
+					"ValidatingWebhookConfiguration",
+					"MutatingWebhookConfiguration",
+				},
+			}
+		},
+	}
+}