fn/framework support for reading from stdin in standalone

- speficy '-' to read from stdin when running standalone

kyaml/fn/framework/framework.go

@@ -95,11 +95,21 @@ type ResourceList struct {
 
 	// NoPrintError if set will prevent the error from being printed
 	NoPrintError bool
+
+	Command *cobra.Command
 }
 
 // Read reads the ResourceList
 func (r *ResourceList) Read() error {
+	var in io.Reader = os.Stdin
+	var out io.Writer = os.Stdout
+	if r.Command != nil {
+		in = r.Command.InOrStdin()
+		out = r.Command.OutOrStdout()
+	}
+
 	// parse the inputs from the args
+	var readStdinStandalone bool
 	if len(r.Args) > 0 && !r.DisableStandalone {
 		// write the files as input
 		var buf bytes.Buffer
@@ -109,6 +119,12 @@ func (r *ResourceList) Read() error {
 			if i == 0 {
 				continue
 			}
+			if r.Args[i] == "-" {
+				// Read stdin separately
+				readStdinStandalone = true
+				continue
+			}
+
 			b, err := ioutil.ReadFile(r.Args[i])
 			if err != nil {
 				return errors.WrapPrefixf(err, "unable to read input file %s", r.Args[i])
@@ -120,10 +136,10 @@ func (r *ResourceList) Read() error {
 	}
 
 	if r.Reader == nil {
-		r.Reader = os.Stdin
+		r.Reader = in
 	}
 	if r.Writer == nil {
-		r.Writer = os.Stdout
+		r.Writer = out
 	}
 	r.rw = &kio.ByteReadWriter{
 		Reader:                r.Reader,
@@ -157,6 +173,16 @@ func (r *ResourceList) Read() error {
 		return errors.Wrap(err)
 	}
 
+	if readStdinStandalone {
+		br := kio.ByteReader{Reader: in}
+		items, err := br.Read()
+		if err != nil {
+			return errors.Wrap(err)
+		}
+		// stdin always comes first so files are patches
+		r.Items = append(items, r.Items...)
+	}
+
 	// parse the functionConfig
 	return func() error {
 		if r.rw.FunctionConfig == nil {
@@ -223,8 +249,9 @@ func (r *ResourceList) Write() error {
 // a Dockerfile to build the function into a container image
 //
 //		go run main.go gen DIR/
-func Command(resourceList *ResourceList, function Function) cobra.Command {
+func Command(resourceList *ResourceList, function Function) *cobra.Command {
 	cmd := cobra.Command{}
+	resourceList.Command = &cmd
 	AddGenerateDockerfile(&cmd)
 	var printStack bool
 	cmd.RunE = func(cmd *cobra.Command, args []string) error {
@@ -242,7 +269,7 @@ func Command(resourceList *ResourceList, function Function) cobra.Command {
 	cmd.Args = cobra.MinimumNArgs(0)
 	cmd.SilenceErrors = true
 	cmd.SilenceUsage = true
-	return cmd
+	return &cmd
 }
 
 // TemplateCommand provides a cobra command to invoke a template
@@ -310,7 +337,7 @@ func (tc TemplateCommand) doTemplate(t *template.Template, rl *ResourceList) err
 }
 
 // GetCommand returns a new cobra command
-func (tc TemplateCommand) GetCommand() cobra.Command {
+func (tc TemplateCommand) GetCommand() *cobra.Command {
 	rl := ResourceList{
 		FunctionConfig: tc.API,
 		NoPrintError:   true,

kyaml/fn/framework/framework_test.go

@@ -4,13 +4,16 @@
 package framework_test
 
 import (
+	"bytes"
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 
 	"github.com/spf13/cobra"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 	"sigs.k8s.io/kustomize/kyaml/fn/framework"
 	"sigs.k8s.io/kustomize/kyaml/fn/framework/frameworktestutil"
 	"sigs.k8s.io/kustomize/kyaml/testutil"
@@ -66,7 +69,7 @@ func TestCommand_standalone(t *testing.T) {
 	var config api
 
 	resourceList := &framework.ResourceList{FunctionConfig: &config}
-	cmdFn := func() cobra.Command {
+	cmdFn := func() *cobra.Command {
 		return framework.Command(resourceList, func() error {
 			resourceList.Items = append(resourceList.Items, yaml.MustParse(`
 apiVersion: apps/v1
@@ -90,3 +93,72 @@ metadata:
 
 	frameworktestutil.ResultsChecker{Command: cmdFn}.Assert(t)
 }
+
+func TestCommand_standalonestdin(t *testing.T) {
+	// TODO: make this test pass on windows -- currently failure seems spurious
+	testutil.SkipWindows(t)
+
+	type api = struct {
+		A string `json:"a" yaml:"a"`
+	}
+	var config api
+
+	resourceList := &framework.ResourceList{FunctionConfig: &config}
+	cmd := framework.Command(resourceList, func() error {
+		resourceList.Items = append(resourceList.Items, yaml.MustParse(`
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: bar2
+  namespace: default
+  annotations:
+    foo: bar2
+`))
+		for i := range resourceList.Items {
+			err := resourceList.Items[i].PipeE(yaml.SetAnnotation("a", config.A))
+			if err != nil {
+				return err
+			}
+		}
+
+		return nil
+	})
+	cmd.SetIn(bytes.NewBufferString(`
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: bar1
+  namespace: default
+  annotations:
+    foo: bar1
+spec:
+  replicas: 1
+`))
+	var out bytes.Buffer
+	cmd.SetOut(&out)
+	cmd.SetArgs([]string{filepath.Join("testdata", "command", "config.yaml"), "-"})
+
+	require.NoError(t, cmd.Execute())
+
+	require.Equal(t, strings.TrimSpace(`
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: bar1
+  namespace: default
+  annotations:
+    foo: bar1
+    a: 'b'
+spec:
+  replicas: 1
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: bar2
+  namespace: default
+  annotations:
+    foo: bar2
+    a: 'b'
+`), strings.TrimSpace(out.String()))
+}

kyaml/fn/framework/frameworktestutil/frameworktestutil.go

@@ -46,7 +46,7 @@ type ResultsChecker struct {
 	ExpectedErrorFilename string
 
 	// Command provides the function to run.
-	Command func() cobra.Command
+	Command func() *cobra.Command
 }
 
 // Assert asserts the results for functions

kyaml/fn/framework/patch_test.go

@@ -21,7 +21,7 @@ func TestPatchTemplate(t *testing.T) {
 	// TODO: make this test pass on windows -- current failure seems spurious
 	testutil.SkipWindows(t)
 
-	cmdFn := func() cobra.Command {
+	cmdFn := func() *cobra.Command {
 		type api struct {
 			Selector framework.Selector `json:"selector" yaml:"selector"`
 			A        string             `json:"a" yaml:"a"`