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>

9 files changed, 120 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)
diff --git a/docs/source/markdown/podman-create.1.md b/docs/source/markdown/podman-create.1.md
index eb73609d4..5e73804ab 100644
--- a/docs/source/markdown/podman-create.1.md
+++ b/docs/source/markdown/podman-create.1.md
@@ -647,6 +647,11 @@ Default is to create a private PID namespace for the container
 
 Tune the container's pids limit. Set `0` to have unlimited pids for the container. (default "4096" on systems that support PIDS cgroups).
 
+#### **--platform**=*OS/ARCH*
+
+Specify the platform for selecting the image.   (Conflicts with override-arch and override-os)
+The `--platform` option can be used to override the current architecture and operating system.
+
 #### **--pod**=*name*
 
 Run container in an existing pod. If you want Podman to make the pod for you, preference the pod name with `new:`.
diff --git a/docs/source/markdown/podman-pull.1.md b/docs/source/markdown/podman-pull.1.md
index 130c54ba9..b28d34c64 100644
--- a/docs/source/markdown/podman-pull.1.md
+++ b/docs/source/markdown/podman-pull.1.md
@@ -89,6 +89,11 @@ Override the OS, defaults to hosts, of the image to be pulled. For example, `win
 
 Use _VARIANT_ instead of the default architecture variant of the container image.  Some images can use multiple variants of the arm architectures, such as arm/v5 and arm/v7.
 
+#### **--platform**=*OS/ARCH*
+
+Specify the platform for selecting the image.  (Conflicts with override-arch and override-os)
+The `--platform` option can be used to override the current architecture and operating system.
+
 #### **--quiet**, **-q**
 
 Suppress output information when pulling images
diff --git a/docs/source/markdown/podman-run.1.md b/docs/source/markdown/podman-run.1.md
index 184c12acd..897210749 100644
--- a/docs/source/markdown/podman-run.1.md
+++ b/docs/source/markdown/podman-run.1.md
@@ -675,6 +675,11 @@ The efault is to create a private PID namespace for the container.
 
 Tune the container's pids limit. Set to **0** to have unlimited pids for the container. The default is **4096** on systems that support "pids" cgroup controller.
 
+#### **--platform**=*OS/ARCH*
+
+Specify the platform for selecting the image.  (Conflicts with override-arch and override-os)
+The `--platform` option can be used to override the current architecture and operating system.
+
 #### **--pod**=*name*
 
 Run container in an existing pod. If you want Podman to make the pod for you, prefix the pod name with **new:**.
diff --git a/test/e2e/create_test.go b/test/e2e/create_test.go
index 760345a67..aaf089d97 100644
--- a/test/e2e/create_test.go
+++ b/test/e2e/create_test.go
@@ -5,6 +5,7 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"runtime"
 	"strings"
 
 	. "github.com/containers/podman/v2/test/utils"
@@ -644,4 +645,35 @@ var _ = Describe("Podman create", func() {
 		Expect(session.ErrorToString()).To(ContainSubstring("unknown flag"))
 	})
 
+	It("podman create --platform", func() {
+		session := podmanTest.Podman([]string{"create", "--platform=linux/bogus", ALPINE})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(125))
+		expectedError := "no image found in manifest list for architecture bogus"
+		Expect(session.ErrorToString()).To(ContainSubstring(expectedError))
+
+		session = podmanTest.Podman([]string{"create", "--platform=linux/arm64", "--override-os", "windows", ALPINE})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(125))
+		expectedError = "--platform option can not be specified with --overide-arch or --override-os"
+		Expect(session.ErrorToString()).To(ContainSubstring(expectedError))
+
+		session = podmanTest.Podman([]string{"create", "-q", "--platform=linux/arm64", ALPINE})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+
+		setup := podmanTest.Podman([]string{"container", "inspect", session.OutputToString()})
+		setup.WaitWithDefaultTimeout()
+		Expect(setup.ExitCode()).To(Equal(0))
+
+		data := setup.InspectContainerToJSON()
+		setup = podmanTest.Podman([]string{"image", "inspect", data[0].Image})
+		setup.WaitWithDefaultTimeout()
+		Expect(setup.ExitCode()).To(Equal(0))
+
+		idata := setup.InspectImageJSON() // returns []inspect.ImageData
+		Expect(len(idata)).To(Equal(1))
+		Expect(idata[0].Os).To(Equal(runtime.GOOS))
+		Expect(idata[0].Architecture).To(Equal("arm64"))
+	})
 })
diff --git a/test/e2e/pull_test.go b/test/e2e/pull_test.go
index f1b055d6d..c572fc5ac 100644
--- a/test/e2e/pull_test.go
+++ b/test/e2e/pull_test.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"runtime"
 	"strings"
 
 	. "github.com/containers/podman/v2/test/utils"
@@ -494,4 +495,31 @@ var _ = Describe("Podman pull", func() {
 			Expect(data[0].ID).To(Equal(image1))
 		}
 	})
+
+	It("podman pull --platform", func() {
+		session := podmanTest.Podman([]string{"pull", "--platform=linux/bogus", ALPINE})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(125))
+		expectedError := "no image found in manifest list for architecture bogus"
+		Expect(session.ErrorToString()).To(ContainSubstring(expectedError))
+
+		session = podmanTest.Podman([]string{"pull", "--platform=linux/arm64", "--override-os", "windows", ALPINE})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(125))
+		expectedError = "--platform option can not be specified with --overide-arch or --override-os"
+		Expect(session.ErrorToString()).To(ContainSubstring(expectedError))
+
+		session = podmanTest.Podman([]string{"pull", "-q", "--platform=linux/arm64", ALPINE})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+
+		setup := podmanTest.Podman([]string{"image", "inspect", session.OutputToString()})
+		setup.WaitWithDefaultTimeout()
+		Expect(setup.ExitCode()).To(Equal(0))
+
+		data := setup.InspectImageJSON() // returns []inspect.ImageData
+		Expect(len(data)).To(Equal(1))
+		Expect(data[0].Os).To(Equal(runtime.GOOS))
+		Expect(data[0].Architecture).To(Equal("arm64"))
+	})
 })