feat: add plugin entrypoint

plugin/v1/api.go

@@ -20,12 +20,12 @@ import (
 	"errors"
 	"fmt"
 
+	"sigs.k8s.io/kubebuilder-declarative-pattern/plugin/v1/scaffolds"
 	"sigs.k8s.io/kubebuilder/v3/pkg/config"
 	"sigs.k8s.io/kubebuilder/v3/pkg/machinery"
 	"sigs.k8s.io/kubebuilder/v3/pkg/model/resource"
 	"sigs.k8s.io/kubebuilder/v3/pkg/plugin"
 	"sigs.k8s.io/kubebuilder/v3/pkg/plugin/util"
-	"sigs.k8s.io/kubebuilder/v3/pkg/plugins/golang/declarative/v1/scaffolds"
 	goPluginV2 "sigs.k8s.io/kubebuilder/v3/pkg/plugins/golang/v2"
 )
 
@@ -111,7 +111,7 @@ func (p *createAPISubcommand) Scaffold(fs machinery.Filesystem) error {
 	if err := p.config.DecodePluginConfig(pluginKey, &cfg); errors.As(err, &config.UnsupportedFieldError{}) {
 		// Config doesn't support per-plugin configuration, so we can't track them
 	} else {
-		// Fail unless they key wasn't found, which just means it is the first resource tracked
+		// Fail unless the key wasn't found, which just means it is the first resource tracked
 		if err != nil && !errors.As(err, &config.PluginKeyNotFoundError{}) {
 			return err
 		}

plugin/v1/cmd/cmd.go

@@ -0,0 +1,85 @@
+/*
+Copyright 2023 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 cmd
+
+import (
+	"bufio"
+	"encoding/json"
+	"fmt"
+	"io"
+	"log"
+	"os"
+
+	"sigs.k8s.io/kubebuilder/v3/pkg/plugin/external"
+)
+
+const (
+	commandInit      = "init"
+	commandCreateApi = "create api"
+)
+
+func returnError(err error) {
+	response := external.PluginResponse{
+		Error:     true,
+		ErrorMsgs: []string{err.Error()},
+	}
+
+	output, err := json.Marshal(response)
+	if err != nil {
+		log.Fatalf("encountered error serializing output: %s | output: %s", err.Error(), output)
+	}
+	fmt.Printf("%s", output)
+}
+
+// Run will run the steps defined by the plugin
+func Run() {
+	// Kubebuilder makes requests to external plugin by writing STDIN.
+	reader := bufio.NewReader(os.Stdin)
+
+	input, err := io.ReadAll(reader)
+	if err != nil {
+		returnError(fmt.Errorf("encountered error reading from STDIN: %+v", err))
+	}
+
+	// Parsing request sent by kubebuilder into a PluginRequest instance.
+	pluginRequest := &external.PluginRequest{}
+
+	if err = json.Unmarshal(input, pluginRequest); err != nil {
+		returnError(err)
+	}
+
+	// Run logic based on the command executed by Kubebuilder.
+	var response external.PluginResponse
+	switch pluginRequest.Command {
+	case commandInit:
+		// handle init command
+	case commandCreateApi:
+		// handle create api command
+	default:
+		response = external.PluginResponse{
+			Error:     true,
+			ErrorMsgs: []string{"unknown subcommand:" + pluginRequest.Command},
+		}
+	}
+
+	output, err := json.Marshal(response)
+	if err != nil {
+		returnError(err)
+	}
+
+	fmt.Printf("%s", output)
+}

plugin/v1/exec/main.go

@@ -0,0 +1,25 @@
+/*
+Copyright 2023 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 (
+	"sigs.k8s.io/kubebuilder-declarative-pattern/plugin/v1/cmd"
+)
+
+func main() {
+	cmd.Run()
+}

plugin/v1/scaffolds/api-new.go

@@ -0,0 +1,33 @@
+/*
+Copyright 2023 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 scaffolds
+
+import (
+	"sigs.k8s.io/kubebuilder/v3/pkg/plugin/external"
+)
+
+// ApiCmd handles all the logic for the `create api` subcommand
+func ApiCmd(pr *external.PluginRequest) external.PluginResponse {
+	pluginResponse := external.PluginResponse{
+		Command:  "init",
+		Universe: pr.Universe,
+	}
+
+	// TODO(@em-r): add logic for handling `create api` command
+
+	return pluginResponse
+}

plugin/v1/scaffolds/init.go

@@ -0,0 +1,33 @@
+/*
+Copyright 2023 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 scaffolds
+
+import (
+	"sigs.k8s.io/kubebuilder/v3/pkg/plugin/external"
+)
+
+// InitCmd handles all the logic for the `init` subcommand
+func InitCmd(pr *external.PluginRequest) external.PluginResponse {
+	pluginResponse := external.PluginResponse{
+		Command:  "init",
+		Universe: pr.Universe,
+	}
+
+	// TODO(@em-r): add logic for handling `init` command
+
+	return pluginResponse
+}