Add shell pipe support for "play kube"

Closes containers#8996

Similar to `cat pod.json | kubectl apply -f -` this commit adds support
for input from shell pipe (ex `cat pod.json | podman play kube -`).
To use input form pipe one may use '-' as file name, the same way as
`kubectl apply -f -`

Signed-off-by: Ádám Kovács <[email protected]>

pkg/bindings/play/play.go

@@ -9,6 +9,7 @@ import (
 	"github.com/containers/podman/v2/pkg/auth"
 	"github.com/containers/podman/v2/pkg/bindings"
 	"github.com/containers/podman/v2/pkg/domain/entities"
+	"github.com/pkg/errors"
 )
 
 func Kube(ctx context.Context, path string, options *KubeOptions) (*entities.PlayKubeReport, error) {
@@ -21,11 +22,27 @@ func Kube(ctx context.Context, path string, options *KubeOptions) (*entities.Pla
 		return nil, err
 	}
 
-	f, err := os.Open(path)
-	if err != nil {
-		return nil, err
+	var f *os.File
+
+	if path == "-" {
+		fi, err := os.Stdin.Stat()
+		if err != nil {
+			return nil, errors.Wrapf(err, "unable to read from stdin")
+		}
+
+		if fi.Mode()&os.ModeNamedPipe == 0 {
+			return nil, errors.New("No data is supplied by a shell pipe but '-' was used as filename")
+		}
+
+		f = os.Stdin
+
+	} else {
+		f, err := os.Open(path)
+		if err != nil {
+			return nil, err
+		}
+		defer f.Close()
 	}
-	defer f.Close()
 
 	params, err := options.ToParams()
 	if err != nil {

pkg/domain/infra/abi/play.go

@@ -1,6 +1,7 @@
 package abi
 
 import (
+	"bufio"
 	"context"
 	"fmt"
 	"io"
@@ -29,9 +30,34 @@ func (ic *ContainerEngine) PlayKube(ctx context.Context, path string, options en
 		kubeObject v1.ObjectReference
 	)
 
-	content, err := ioutil.ReadFile(path)
-	if err != nil {
-		return nil, err
+	var content []byte
+	var err error
+
+	if path == "-" {
+		fi, err := os.Stdin.Stat()
+		if err != nil {
+			return nil, errors.Wrapf(err, "unable to read from stdin")
+		}
+
+		if fi.Mode()&os.ModeNamedPipe == 0 {
+			return nil, errors.New("No data is supplied by a shell pipe but '-' was used as filename")
+		}
+
+		reader := bufio.NewReader(os.Stdin)
+
+		for {
+			input, err := reader.ReadByte()
+			if err != nil && err == io.EOF {
+				break
+			}
+			content = append(content, input)
+		}
+
+	} else {
+		content, err = ioutil.ReadFile(path)
+		if err != nil {
+			return nil, err
+		}
 	}
 
 	if err := yaml.Unmarshal(content, &kubeObject); err != nil {