added shell command (#158)

* added shell command input to commands prepending shell

* Added shell command and test

pkg/commands/cmd.go

@@ -35,8 +35,13 @@ func (c *CmdCommand) ExecuteCommand(config *v1.Config) error {
 	var newCommand []string
 	if c.cmd.PrependShell {
 		// This is the default shell on Linux
-		// TODO: Support shell command here
-		shell := []string{"/bin/sh", "-c"}
+		var shell []string
+		if len(config.Shell) > 0 {
+			shell = config.Shell
+		} else {
+			shell = append(shell, "/bin/sh", "-c")
+		}
+
 		newCommand = append(shell, strings.Join(c.cmd.CmdLine, " "))
 	} else {
 		newCommand = c.cmd.CmdLine

pkg/commands/entrypoint.go

@@ -34,8 +34,13 @@ func (e *EntrypointCommand) ExecuteCommand(config *v1.Config) error {
 	var newCommand []string
 	if e.cmd.PrependShell {
 		// This is the default shell on Linux
-		// TODO: Support shell command here
-		shell := []string{"/bin/sh", "-c"}
+		var shell []string
+		if len(config.Shell) > 0 {
+			shell = config.Shell
+		} else {
+			shell = append(shell, "/bin/sh", "-c")
+		}
+
 		newCommand = append(shell, strings.Join(e.cmd.CmdLine, " "))
 	} else {
 		newCommand = e.cmd.CmdLine

pkg/commands/run.go

@@ -36,8 +36,13 @@ func (r *RunCommand) ExecuteCommand(config *v1.Config) error {
 	var newCommand []string
 	if r.cmd.PrependShell {
 		// This is the default shell on Linux
-		// TODO: Support shell command here
-		shell := []string{"/bin/sh", "-c"}
+		var shell []string
+		if len(config.Shell) > 0 {
+			shell = config.Shell
+		} else {
+			shell = append(shell, "/bin/sh", "-c")
+		}
+
 		newCommand = append(shell, strings.Join(r.cmd.CmdLine, " "))
 	} else {
 		newCommand = r.cmd.CmdLine

pkg/commands/shell.go

@@ -0,0 +1,54 @@
+/*
+Copyright 2018 Google LLC
+
+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 commands
+
+import (
+	"strings"
+
+	"github.com/docker/docker/builder/dockerfile/instructions"
+	"github.com/google/go-containerregistry/v1"
+	"github.com/sirupsen/logrus"
+)
+
+type ShellCommand struct {
+	cmd *instructions.ShellCommand
+}
+
+// ExecuteCommand handles command processing similar to CMD and RUN,
+func (s *ShellCommand) ExecuteCommand(config *v1.Config) error {
+	logrus.Info("cmd: SHELL")
+	var newShell []string
+
+	newShell = s.cmd.Shell
+
+	logrus.Infof("Replacing Shell in config with %v", newShell)
+	config.Shell = newShell
+	return nil
+}
+
+// FilesToSnapshot returns an empty array since this is a metadata command
+func (s *ShellCommand) FilesToSnapshot() []string {
+	return []string{}
+}
+
+// CreatedBy returns some information about the command for the image config history
+func (s *ShellCommand) CreatedBy() string {
+	entrypoint := []string{"SHELL"}
+	cmdLine := strings.Join(s.cmd.Shell, " ")
+
+	return strings.Join(append(entrypoint, cmdLine), " ")
+}

pkg/commands/shell_test.go

@@ -0,0 +1,55 @@
+/*
+Copyright 2018 Google LLC
+
+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 commands
+
+import (
+	"testing"
+
+	"github.com/GoogleContainerTools/kaniko/testutil"
+	"github.com/docker/docker/builder/dockerfile/instructions"
+	"github.com/google/go-containerregistry/v1"
+)
+
+var shellTests = []struct {
+	cmdLine       []string
+	expectedShell []string
+}{
+	{
+		cmdLine:       []string{"/bin/bash", "-c"},
+		expectedShell: []string{"/bin/bash", "-c"},
+	},
+	{
+		cmdLine:       []string{"/bin/bash"},
+		expectedShell: []string{"/bin/bash"},
+	},
+}
+
+func TestShellExecuteCmd(t *testing.T) {
+
+	cfg := &v1.Config{
+		Shell: nil,
+	}
+
+	for _, test := range shellTests {
+		cmd := ShellCommand{
+			&instructions.ShellCommand{
+				Shell: test.cmdLine,
+			},
+		}
+		err := cmd.ExecuteCommand(cfg)
+		testutil.CheckErrorAndDeepEqual(t, false, err, test.expectedShell, cfg.Shell)
+	}
+}