LCOW: Set correct default shell for platform in builder

Signed-off-by: John Howard <jhoward@microsoft.com>

builder/dockerfile/builder_unix.go

@@ -2,4 +2,6 @@
 
 package dockerfile
 
-var defaultShell = []string{"/bin/sh", "-c"}
+func defaultShellForPlatform(platform string) []string {
+	return []string{"/bin/sh", "-c"}
+}

builder/dockerfile/builder_windows.go

@@ -1,3 +1,8 @@
 package dockerfile
 
-var defaultShell = []string{"cmd", "/S", "/C"}
+func defaultShellForPlatform(platform string) []string {
+	if platform == "linux" {
+		return []string{"/bin/sh", "-c"}
+	}
+	return []string{"cmd", "/S", "/C"}
+}

builder/dockerfile/dispatchers.go

@@ -399,7 +399,7 @@ func workdir(req dispatchRequest) error {
 	}
 
 	comment := "WORKDIR " + runConfig.WorkingDir
-	runConfigWithCommentCmd := copyRunConfig(runConfig, withCmdCommentString(comment))
+	runConfigWithCommentCmd := copyRunConfig(runConfig, withCmdCommentString(comment, req.builder.platform))
 	containerID, err := req.builder.probeAndCreate(req.state, runConfigWithCommentCmd)
 	if err != nil || containerID == "" {
 		return err
@@ -417,7 +417,7 @@ func workdir(req dispatchRequest) error {
 // the current SHELL which defaults to 'sh -c' under linux or 'cmd /S /C' under
 // Windows, in the event there is only one argument The difference in processing:
 //
-// RUN echo hi          # sh -c echo hi       (Linux)
+// RUN echo hi          # sh -c echo hi       (Linux and LCOW)
 // RUN echo hi          # cmd /S /C echo hi   (Windows)
 // RUN [ "echo", "hi" ] # echo hi
 //
@@ -433,7 +433,7 @@ func run(req dispatchRequest) error {
 	stateRunConfig := req.state.runConfig
 	args := handleJSONArgs(req.args, req.attributes)
 	if !req.attributes["json"] {
-		args = append(getShell(stateRunConfig), args...)
+		args = append(getShell(stateRunConfig, req.builder.platform), args...)
 	}
 	cmdFromArgs := strslice.StrSlice(args)
 	buildArgs := req.builder.buildArgs.FilterAllowed(stateRunConfig.Env)
@@ -518,7 +518,7 @@ func cmd(req dispatchRequest) error {
 	runConfig := req.state.runConfig
 	cmdSlice := handleJSONArgs(req.args, req.attributes)
 	if !req.attributes["json"] {
-		cmdSlice = append(getShell(runConfig), cmdSlice...)
+		cmdSlice = append(getShell(runConfig, req.builder.platform), cmdSlice...)
 	}
 
 	runConfig.Cmd = strslice.StrSlice(cmdSlice)
@@ -670,7 +670,7 @@ func entrypoint(req dispatchRequest) error {
 		runConfig.Entrypoint = nil
 	default:
 		// ENTRYPOINT echo hi
-		runConfig.Entrypoint = strslice.StrSlice(append(getShell(runConfig), parsed[0]))
+		runConfig.Entrypoint = strslice.StrSlice(append(getShell(runConfig, req.builder.platform), parsed[0]))
 	}
 
 	// when setting the entrypoint if a CMD was not explicitly set then

builder/dockerfile/dispatchers_test.go

@@ -474,7 +474,7 @@ func TestRunWithBuildArgs(t *testing.T) {
 
 	runConfig := &container.Config{}
 	origCmd := strslice.StrSlice([]string{"cmd", "in", "from", "image"})
-	cmdWithShell := strslice.StrSlice(append(getShell(runConfig), "echo foo"))
+	cmdWithShell := strslice.StrSlice(append(getShell(runConfig, runtime.GOOS), "echo foo"))
 	envVars := []string{"|1", "one=two"}
 	cachedCmd := strslice.StrSlice(append(envVars, cmdWithShell...))
 

builder/dockerfile/internals.go

@@ -25,7 +25,7 @@ func (b *Builder) commit(dispatchState *dispatchState, comment string) error {
 		return errors.New("Please provide a source image with `from` prior to commit")
 	}
 
-	runConfigWithCommentCmd := copyRunConfig(dispatchState.runConfig, withCmdComment(comment))
+	runConfigWithCommentCmd := copyRunConfig(dispatchState.runConfig, withCmdComment(comment, b.platform))
 	hit, err := b.probeCache(dispatchState, runConfigWithCommentCmd)
 	if err != nil || hit {
 		return err
@@ -110,7 +110,7 @@ func (b *Builder) performCopy(state *dispatchState, inst copyInstruction) error
 	// TODO: should this have been using origPaths instead of srcHash in the comment?
 	runConfigWithCommentCmd := copyRunConfig(
 		state.runConfig,
-		withCmdCommentString(fmt.Sprintf("%s %s in %s ", inst.cmdName, srcHash, inst.dest)))
+		withCmdCommentString(fmt.Sprintf("%s %s in %s ", inst.cmdName, srcHash, inst.dest), b.platform))
 	hit, err := b.probeCache(state, runConfigWithCommentCmd)
 	if err != nil || hit {
 		return err
@@ -190,9 +190,9 @@ func withCmd(cmd []string) runConfigModifier {
 
 // withCmdComment sets Cmd to a nop comment string. See withCmdCommentString for
 // why there are two almost identical versions of this.
-func withCmdComment(comment string) runConfigModifier {
+func withCmdComment(comment string, platform string) runConfigModifier {
 	return func(runConfig *container.Config) {
-		runConfig.Cmd = append(getShell(runConfig), "#(nop) ", comment)
+		runConfig.Cmd = append(getShell(runConfig, platform), "#(nop) ", comment)
 	}
 }
 
@@ -200,9 +200,9 @@ func withCmdComment(comment string) runConfigModifier {
 // A few instructions (workdir, copy, add) used a nop comment that is a single arg
 // where as all the other instructions used a two arg comment string. This
 // function implements the single arg version.
-func withCmdCommentString(comment string) runConfigModifier {
+func withCmdCommentString(comment string, platform string) runConfigModifier {
 	return func(runConfig *container.Config) {
-		runConfig.Cmd = append(getShell(runConfig), "#(nop) "+comment)
+		runConfig.Cmd = append(getShell(runConfig, platform), "#(nop) "+comment)
 	}
 }
 
@@ -229,9 +229,9 @@ func withEntrypointOverride(cmd []string, entrypoint []string) runConfigModifier
 
 // getShell is a helper function which gets the right shell for prefixing the
 // shell-form of RUN, ENTRYPOINT and CMD instructions
-func getShell(c *container.Config) []string {
+func getShell(c *container.Config, platform string) []string {
 	if 0 == len(c.Shell) {
-		return append([]string{}, defaultShell[:]...)
+		return append([]string{}, defaultShellForPlatform(platform)[:]...)
 	}
 	return append([]string{}, c.Shell[:]...)
 }

builder/dockerfile/internals_test.go

@@ -2,6 +2,7 @@ package dockerfile
 
 import (
 	"fmt"
+	"runtime"
 	"testing"
 
 	"github.com/docker/docker/api/types"
@@ -97,9 +98,9 @@ func TestCopyRunConfig(t *testing.T) {
 		},
 		{
 			doc:       "Set the command to a comment",
-			modifiers: []runConfigModifier{withCmdComment("comment")},
+			modifiers: []runConfigModifier{withCmdComment("comment", runtime.GOOS)},
 			expected: &container.Config{
-				Cmd: append(defaultShell, "#(nop) ", "comment"),
+				Cmd: append(defaultShellForPlatform(runtime.GOOS), "#(nop) ", "comment"),
 				Env: defaultEnv,
 			},
 		},