Support for source and sink with functions

cmd/config/internal/commands/source.go

@@ -0,0 +1,77 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package commands
+
+import (
+	"fmt"
+
+	"github.com/spf13/cobra"
+	"sigs.k8s.io/kustomize/cmd/config/internal/generateddocs/commands"
+	"sigs.k8s.io/kustomize/kyaml/kio"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+// GetSourceRunner returns a command for Source.
+func GetSourceRunner(name string) *SourceRunner {
+	r := &SourceRunner{}
+	c := &cobra.Command{
+		Use:     "source DIR",
+		Short:   commands.SourceShort,
+		Long:    commands.SourceLong,
+		Example: commands.SourceExamples,
+		RunE:    r.runE,
+		Args:    cobra.ExactArgs(1),
+	}
+	fixDocs(name, c)
+	c.Flags().StringVar(&r.WrapKind, "wrap-kind", kio.ResourceListKind,
+		"output using this format.")
+	c.Flags().StringVar(&r.WrapApiVersion, "wrap-version", kio.ResourceListAPIVersion,
+		"output using this format.")
+	c.Flags().StringVar(&r.FunctionConfig, "function-config", "",
+		"path to function config.")
+	r.Command = c
+	_ = c.MarkFlagFilename("function-config", "yaml", "json", "yml")
+	return r
+}
+
+func SourceCommand(name string) *cobra.Command {
+	return GetSourceRunner(name).Command
+}
+
+// SourceRunner contains the run function
+type SourceRunner struct {
+	WrapKind       string
+	WrapApiVersion string
+	FunctionConfig string
+	Command        *cobra.Command
+}
+
+func (r *SourceRunner) runE(c *cobra.Command, args []string) error {
+	// if there is a function-config specified, emit it
+	var functionConfig *yaml.RNode
+	if r.FunctionConfig != "" {
+		configs, err := kio.LocalPackageReader{PackagePath: r.FunctionConfig}.Read()
+		if err != nil {
+			return err
+		}
+		if len(configs) != 1 {
+			return fmt.Errorf("expected exactly 1 functionConfig, found %d", len(configs))
+		}
+		functionConfig = configs[0]
+	}
+
+	var outputs []kio.Writer
+	outputs = append(outputs, kio.ByteWriter{
+		Writer:                c.OutOrStdout(),
+		KeepReaderAnnotations: true,
+		WrappingKind:          r.WrapKind,
+		WrappingAPIVersion:    r.WrapApiVersion,
+		FunctionConfig:        functionConfig,
+	})
+
+	err := kio.Pipeline{
+		Inputs:  []kio.Reader{kio.LocalPackageReader{PackagePath: args[0]}},
+		Outputs: outputs}.Execute()
+	return handleError(c, err)
+}