Add support for --platform

For docker compatibility we need to support --platform
flag.

podman create --platform
podman run --platform
podman pull --platform

Since we have --override-os and --override-arch already
this can be done just by modifying the client to split
the --platform call into os and arch and then pass those
options to the server side.

Fixes: https://github.com/containers/podman/issues/6244

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

4 files changed, 45 insertions, 0 deletions

diff --git a/cmd/podman/common/create.go b/cmd/podman/common/create.go
index 599b430ea..14086ace4 100644
--- a/cmd/podman/common/create.go
+++ b/cmd/podman/common/create.go
@@ -513,6 +513,14 @@ func DefineCreateFlags(cmd *cobra.Command, cf *ContainerCLIOpts) {
 	)
 	_ = cmd.RegisterFlagCompletionFunc(pidsLimitFlagName, completion.AutocompleteNone)
 
+	platformFlagName := "platform"
+	createFlags.StringVar(
+		&cf.Platform,
+		platformFlagName, "",
+		"Specify the platform for selecting the image.  (Conflicts with override-arch and override-os)",
+	)
+	_ = cmd.RegisterFlagCompletionFunc(platformFlagName, completion.AutocompleteNone)
+
 	podFlagName := "pod"
 	createFlags.StringVar(
 		&cf.Pod,
diff --git a/cmd/podman/common/create_opts.go b/cmd/podman/common/create_opts.go
index 6dc43dbc6..24ede4885 100644
--- a/cmd/podman/common/create_opts.go
+++ b/cmd/podman/common/create_opts.go
@@ -78,6 +78,7 @@ type ContainerCLIOpts struct {
 	OverrideVariant   string
 	PID               string
 	PIDsLimit         *int64
+	Platform          string
 	Pod               string
 	PodIDFile         string
 	PreserveFDs       uint
diff --git a/cmd/podman/containers/create.go b/cmd/podman/containers/create.go
index db920554e..3d87c71a9 100644
--- a/cmd/podman/containers/create.go
+++ b/cmd/podman/containers/create.go
@@ -18,6 +18,7 @@ import (
 	"github.com/containers/podman/v2/pkg/specgen"
 	"github.com/containers/podman/v2/pkg/util"
 	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
 )
 
@@ -236,6 +237,21 @@ func pullImage(imageName string) (string, error) {
 		imageMissing = !br.Value
 	}
 
+	if cliVals.Platform != "" {
+		if cliVals.OverrideArch != "" || cliVals.OverrideOS != "" {
+			return "", errors.Errorf("--platform option can not be specified with --overide-arch or --override-os")
+		}
+		split := strings.SplitN(cliVals.Platform, "/", 2)
+		cliVals.OverrideOS = split[0]
+		if len(split) > 1 {
+			cliVals.OverrideArch = split[1]
+		}
+		if pullPolicy != config.PullImageAlways {
+			logrus.Info("--platform causes the pull policy to be \"always\"")
+			pullPolicy = config.PullImageAlways
+		}
+	}
+
 	if imageMissing || pullPolicy == config.PullImageAlways {
 		if pullPolicy == config.PullImageNever {
 			return "", errors.Wrapf(define.ErrNoSuchImage, "unable to find a name and tag match for %s in repotags", imageName)
diff --git a/cmd/podman/images/pull.go b/cmd/podman/images/pull.go
index a6f41688c..f8e1ee226 100644
--- a/cmd/podman/images/pull.go
+++ b/cmd/podman/images/pull.go
@@ -3,6 +3,7 @@ package images
 import (
 	"fmt"
 	"os"
+	"strings"
 
 	"github.com/containers/common/pkg/auth"
 	"github.com/containers/common/pkg/completion"
@@ -11,6 +12,7 @@ import (
 	"github.com/containers/podman/v2/cmd/podman/registry"
 	"github.com/containers/podman/v2/pkg/domain/entities"
 	"github.com/containers/podman/v2/pkg/util"
+	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
 )
 
@@ -94,6 +96,10 @@ func pullFlags(cmd *cobra.Command) {
 	flags.StringVar(&pullOptions.OverrideVariant, overrideVariantFlagName, "", " use VARIANT instead of the running architecture variant for choosing images")
 	_ = cmd.RegisterFlagCompletionFunc(overrideVariantFlagName, completion.AutocompleteNone)
 
+	platformFlagName := "platform"
+	flags.String(platformFlagName, "", "Specify the platform for selecting the image.  (Conflicts with override-arch and override-os)")
+	_ = cmd.RegisterFlagCompletionFunc(platformFlagName, completion.AutocompleteNone)
+
 	flags.Bool("disable-content-trust", false, "This is a Docker specific option and is a NOOP")
 	flags.BoolVarP(&pullOptions.Quiet, "quiet", "q", false, "Suppress output information when pulling images")
 	flags.StringVar(&pullOptions.SignaturePolicy, "signature-policy", "", "`Pathname` of signature policy file (not usually used)")
@@ -127,6 +133,20 @@ func imagePull(cmd *cobra.Command, args []string) error {
 			return err
 		}
 	}
+	platform, err := cmd.Flags().GetString("platform")
+	if err != nil {
+		return err
+	}
+	if platform != "" {
+		if pullOptions.OverrideArch != "" || pullOptions.OverrideOS != "" {
+			return errors.Errorf("--platform option can not be specified with --overide-arch or --override-os")
+		}
+		split := strings.SplitN(platform, "/", 2)
+		pullOptions.OverrideOS = split[0]
+		if len(split) > 1 {
+			pullOptions.OverrideArch = split[1]
+		}
+	}
 
 	if pullOptions.CredentialsCLI != "" {
 		creds, err := util.ParseRegistryCreds(pullOptions.CredentialsCLI)