util: add platformutil

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

bake/bake.go

@@ -8,6 +8,7 @@ import (
 	"github.com/moby/buildkit/session/auth/authprovider"
 	"github.com/pkg/errors"
 	"github.com/tonistiigi/buildx/build"
+	"github.com/tonistiigi/buildx/util/platformutil"
 )
 
 func ReadTargets(ctx context.Context, files, targets, overrides []string) (map[string]Target, error) {
@@ -254,7 +255,7 @@ func toBuildOpt(t Target) (*build.Options, error) {
 		// CacheFrom: t.CacheFrom,
 	}
 
-	platforms, err := build.ParsePlatformSpecs(t.Platforms)
+	platforms, err := platformutil.Parse(t.Platforms)
 	if err != nil {
 		return nil, err
 	}

commands/build.go

@@ -14,6 +14,7 @@ import (
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 	"github.com/tonistiigi/buildx/build"
+	"github.com/tonistiigi/buildx/util/platformutil"
 	"github.com/tonistiigi/buildx/util/progress"
 )
 
@@ -92,7 +93,7 @@ func runBuild(dockerCli command.Cli, in buildOptions) error {
 		NetworkMode: in.networkMode,
 	}
 
-	platforms, err := build.ParsePlatformSpecs(in.platforms)
+	platforms, err := platformutil.Parse(in.platforms)
 	if err != nil {
 		return err
 	}

util/platformutil/parse.go

@@ -1,4 +1,4 @@
-package build
+package platformutil
 
 import (
 	"strings"
@@ -7,7 +7,7 @@ import (
 	specs "github.com/opencontainers/image-spec/specs-go/v1"
 )
 
-func ParsePlatformSpecs(platformsStr []string) ([]specs.Platform, error) {
+func Parse(platformsStr []string) ([]specs.Platform, error) {
 	if len(platformsStr) == 0 {
 		return nil, nil
 	}
@@ -15,7 +15,7 @@ func ParsePlatformSpecs(platformsStr []string) ([]specs.Platform, error) {
 	for _, s := range platformsStr {
 		parts := strings.Split(s, ",")
 		if len(parts) > 1 {
-			p, err := ParsePlatformSpecs(parts)
+			p, err := Parse(parts)
 			if err != nil {
 				return nil, err
 			}