Add squash-all, fix squash option in build

Translate the podman build --squash command to podman build --layers=false which
has the same functionality as docker build --squash. Add a new option --squash-all
which will squash all layers into one. This will be translated to buildah bud --squash
for the buildah bud api.

Also allow only one option, squash, layers or squash--all to be used per build command.

Fixes: https://github.com/containers/buildah/issues/1234

Signed-off-by: TomSweeneyRedHat <tsweeney@redhat.com>

4 files changed, 55 insertions, 2 deletions

diff --git a/cmd/podman/build.go b/cmd/podman/build.go
index 4ea4d3825..f4efea544 100644
--- a/cmd/podman/build.go
+++ b/cmd/podman/build.go
@@ -17,6 +17,7 @@ import (
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
+	"github.com/spf13/pflag"
 )
 
 var (
@@ -27,6 +28,7 @@ var (
 	fromAndBudValues buildahcli.FromAndBudResults
 	userNSValues     buildahcli.UserNSResults
 	namespaceValues  buildahcli.NameSpaceResults
+	podBuildValues   cliconfig.PodmanBuildResults
 
 	_buildCommand = &cobra.Command{
 		Use:   "build [flags] CONTEXT",
@@ -40,6 +42,7 @@ var (
 			buildCommand.FromAndBudResults = &fromAndBudValues
 			buildCommand.LayerResults = &layerValues
 			buildCommand.NameSpaceResults = &namespaceValues
+			buildCommand.PodmanBuildResults = &podBuildValues
 			buildCommand.Remote = remoteclient
 			return buildCmd(&buildCommand)
 		},
@@ -73,15 +76,30 @@ func init() {
 		logrus.Error("unable to set force-rm flag to true")
 	}
 	flag.DefValue = "true"
+	podmanBuildFlags := GetPodmanBuildFlags(&podBuildValues)
+	flag = podmanBuildFlags.Lookup("squash-all")
+	if err := flag.Value.Set("false"); err != nil {
+		logrus.Error("unable to set squash-all flag to false")
+	}
 
+	flag.DefValue = "true"
 	fromAndBugFlags := buildahcli.GetFromAndBudFlags(&fromAndBudValues, &userNSValues, &namespaceValues)
 
 	flags.AddFlagSet(&budFlags)
-	flags.AddFlagSet(&layerFlags)
 	flags.AddFlagSet(&fromAndBugFlags)
+	flags.AddFlagSet(&layerFlags)
+	flags.AddFlagSet(&podmanBuildFlags)
 	markFlagHidden(flags, "signature-policy")
 }
 
+// GetPodmanBuildFlags flags used only by `podman build` and not by
+// `buildah bud`.
+func GetPodmanBuildFlags(flags *cliconfig.PodmanBuildResults) pflag.FlagSet {
+	fs := pflag.FlagSet{}
+	fs.BoolVar(&flags.SquashAll, "squash-all", false, "Squash all layers into a single layer.")
+	return fs
+}
+
 func getContainerfiles(files []string) []string {
 	var containerfiles []string
 	for _, f := range files {
@@ -119,6 +137,12 @@ func getNsValues(c *cliconfig.BuildValues) ([]buildah.NamespaceOption, error) {
 }
 
 func buildCmd(c *cliconfig.BuildValues) error {
+	if (c.Flags().Changed("squash") && c.Flags().Changed("layers")) ||
+		(c.Flags().Changed("squash-all") && c.Flags().Changed("layers")) ||
+		(c.Flags().Changed("squash-all") && c.Flags().Changed("squash")) {
+		return fmt.Errorf("cannot specify squash, squash-all and layers options together")
+	}
+
 	// The following was taken directly from containers/buildah/cmd/bud.go
 	// TODO Find a away to vendor more of this in rather than copy from bud
 	output := ""
@@ -293,6 +317,22 @@ func buildCmd(c *cliconfig.BuildValues) error {
 		Volumes:      c.Volumes,
 	}
 
+	// `buildah bud --layers=false` acts like `docker build --squash` does.
+	// That is all of the new layers created during the build process are
+	// condensed into one, any layers present prior to this build are retained
+	// without condensing.  `buildah bud --squash` squashes both new and old
+	// layers down into one.  Translate Podman commands into Buildah.
+	// Squash invoked, retain old layers, squash new layers into one.
+	if c.Flags().Changed("squash") && c.Squash {
+		c.Squash = false
+		layers = false
+	}
+	// Squash-all invoked, squash both new and old layers into one.
+	if c.Flags().Changed("squash-all") {
+		c.Squash = true
+		layers = false
+	}
+
 	options := imagebuildah.BuildOptions{
 		CommonBuildOpts:         &buildOpts,
 		AdditionalTags:          tags,
diff --git a/cmd/podman/cliconfig/create.go b/cmd/podman/cliconfig/create.go
index 5fb2eed10..c27dfbbee 100644
--- a/cmd/podman/cliconfig/create.go
+++ b/cmd/podman/cliconfig/create.go
@@ -12,13 +12,20 @@ type RunValues struct {
 	PodmanCommand
 }
 
+// PodmanBuildResults represents the results for Podman Build flags
+// that are unique to Podman.
+type PodmanBuildResults struct {
+	SquashAll bool
+}
+
 type BuildValues struct {
 	PodmanCommand
 	*buildahcli.BudResults
 	*buildahcli.UserNSResults
 	*buildahcli.FromAndBudResults
-	*buildahcli.NameSpaceResults
 	*buildahcli.LayerResults
+	*buildahcli.NameSpaceResults
+	*PodmanBuildResults
 }
 
 type CpValues struct {
diff --git a/completions/bash/podman b/completions/bash/podman
index 4bc387871..2a55183bd 100644
--- a/completions/bash/podman
+++ b/completions/bash/podman
@@ -1246,6 +1246,7 @@ _podman_build() {
 	  -q
 	  --rm
 	  --squash
+	  --squash-all
 	  --tls-verify
   "
 
diff --git a/docs/podman-build.1.md b/docs/podman-build.1.md
index c16d964a9..567d0ead3 100644
--- a/docs/podman-build.1.md
+++ b/docs/podman-build.1.md
@@ -405,6 +405,11 @@ If you omit the unit, the system uses bytes. If you omit the size entirely, the
 
 **--squash**
 
+Squash all of the image's new layers into a single new layer; any preexisting layers
+are not squashed.
+
+**--squash-all**
+
 Squash all of the new image's layers (including those inherited from a base image) into a single new layer.
 
 **--tag**, **-t**=*imageName*