support --compose-file - as stdin

Signed-off-by: Marco Mariani <marco.mariani@alterway.fr>

cli/command/stack/deploy_composefile.go

@@ -2,6 +2,7 @@ package stack
 
 import (
 	"fmt"
+	"io"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -22,7 +23,7 @@ import (
 )
 
 func deployCompose(ctx context.Context, dockerCli command.Cli, opts deployOptions) error {
-	configDetails, err := getConfigDetails(opts.composefile)
+	configDetails, err := getConfigDetails(opts.composefile, dockerCli.In())
 	if err != nil {
 		return err
 	}
@@ -118,16 +119,24 @@ func propertyWarnings(properties map[string]string) string {
 	return strings.Join(msgs, "\n\n")
 }
 
-func getConfigDetails(composefile string) (composetypes.ConfigDetails, error) {
+func getConfigDetails(composefile string, stdin io.Reader) (composetypes.ConfigDetails, error) {
 	var details composetypes.ConfigDetails
 
-	absPath, err := filepath.Abs(composefile)
-	if err != nil {
-		return details, err
+	if composefile == "-" {
+		workingDir, err := os.Getwd()
+		if err != nil {
+			return details, err
+		}
+		details.WorkingDir = workingDir
+	} else {
+		absPath, err := filepath.Abs(composefile)
+		if err != nil {
+			return details, err
+		}
+		details.WorkingDir = filepath.Dir(absPath)
 	}
-	details.WorkingDir = filepath.Dir(absPath)
 
-	configFile, err := getConfigFile(composefile)
+	configFile, err := getConfigFile(composefile, stdin)
 	if err != nil {
 		return details, err
 	}
@@ -150,15 +159,24 @@ func buildEnvironment(env []string) (map[string]string, error) {
 	return result, nil
 }
 
-func getConfigFile(filename string) (*composetypes.ConfigFile, error) {
-	bytes, err := ioutil.ReadFile(filename)
+func getConfigFile(filename string, stdin io.Reader) (*composetypes.ConfigFile, error) {
+	var bytes []byte
+	var err error
+
+	if filename == "-" {
+		bytes, err = ioutil.ReadAll(stdin)
+	} else {
+		bytes, err = ioutil.ReadFile(filename)
+	}
 	if err != nil {
 		return nil, err
 	}
+
 	config, err := loader.ParseYAML(bytes)
 	if err != nil {
 		return nil, err
 	}
+
 	return &composetypes.ConfigFile{
 		Filename: filename,
 		Config:   config,

cli/command/stack/deploy_composefile_test.go

@@ -3,6 +3,7 @@ package stack
 import (
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 
 	"github.com/docker/cli/cli/internal/test/network"
@@ -25,13 +26,29 @@ services:
 	file := tempfile.NewTempFile(t, "test-get-config-details", content)
 	defer file.Remove()
 
-	details, err := getConfigDetails(file.Name())
+	details, err := getConfigDetails(file.Name(), nil)
 	require.NoError(t, err)
 	assert.Equal(t, filepath.Dir(file.Name()), details.WorkingDir)
 	assert.Len(t, details.ConfigFiles, 1)
 	assert.Len(t, details.Environment, len(os.Environ()))
 }
 
+func TestGetConfigDetailsStdin(t *testing.T) {
+	content := `
+version: "3.0"
+services:
+foo:
+image: alpine:3.5
+`
+	details, err := getConfigDetails("-", strings.NewReader(content))
+	require.NoError(t, err)
+	cwd, err := os.Getwd()
+	require.NoError(t, err)
+	assert.Equal(t, cwd, details.WorkingDir)
+	assert.Len(t, details.ConfigFiles, 1)
+	assert.Len(t, details.Environment, len(os.Environ()))
+}
+
 type notFound struct {
 	error
 }

docs/reference/commandline/stack_deploy.md

@@ -57,6 +57,8 @@ Creating service vossibility_ghollector
 Creating service vossibility_lookupd
 ```
 
+The Compose file can also be provided as standard input with `--compose-file -`.
+
 Only a single Compose file is accepted. If your configuration is split between
 multiple Compose files, e.g. a base configuration and environment-specific overrides,
 you can combine these by passing them to `docker-compose config` with the `-f` option