create: support images with invalid platform

Much to my regret, there is a number of images in the wild with invalid
platforms breaking the platform checks in libimage that want to make
sure that a local image is matching the expected platform.

Imagine a `podman run --arch=arm64 fedora` with a local amd64 fedora
image.  We really shouldn't use the local one in this case and pull down
the arm64 one.

The strict platform checks in libimage in combination with invalid
platforms in images surfaced in Podman being able to pull an image but
failing to look it up in subsequent presence checks.  A `podman run`
would hence pull such an image but fail to create the container.

Support images with invalid platforms by vendoring the latest HEAD from
containers/common.  Also remove the partially implemented pull-policy
logic from Podman and let libimage handle that entirely.  However,
whenever --arch, --os or --platform are specified, the pull policy will
be forced to "newer".  This way, we pessimistically assume that the
local image has an invalid platform and we reach out to the registry.
If there's a newer image (i.e., one with a different digest), we'll pull
it down.

Please note that most of the logic has either already been implemented
in libimage or been moved down which allows for removing some clutter
from Podman.

[NO TESTS NEEDED] since c/common has new tests.  Podman can rely on the
existing tests.

Fixes: #10648
Fixes: #10682
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

1 files changed, 17 insertions, 41 deletions

diff --git a/cmd/podman/containers/create.go b/cmd/podman/containers/create.go
index f06869c4e..52cf8fea4 100644
--- a/cmd/podman/containers/create.go
+++ b/cmd/podman/containers/create.go
@@ -8,7 +8,6 @@ import (
 	"strings"
 
 	"github.com/containers/common/pkg/config"
-	storageTransport "github.com/containers/image/v5/storage"
 	"github.com/containers/image/v5/transports/alltransports"
 	"github.com/containers/podman/v3/cmd/podman/common"
 	"github.com/containers/podman/v3/cmd/podman/registry"
@@ -16,9 +15,7 @@ import (
 	"github.com/containers/podman/v3/pkg/domain/entities"
 	"github.com/containers/podman/v3/pkg/specgen"
 	"github.com/containers/podman/v3/pkg/util"
-	"github.com/containers/storage"
 	"github.com/pkg/errors"
-	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
 )
 
@@ -238,30 +235,12 @@ func createInit(c *cobra.Command) error {
 	return nil
 }
 
-// TODO: we should let the backend take care of the pull policy (which it
-// does!). The code below is at risk of causing regression and code divergence.
 func pullImage(imageName string) (string, error) {
 	pullPolicy, err := config.ValidatePullPolicy(cliVals.Pull)
 	if err != nil {
 		return "", err
 	}
 
-	// Check if the image is missing and hence if we need to pull it.
-	imageMissing := true
-	imageRef, err := alltransports.ParseImageName(imageName)
-	switch {
-	case err != nil:
-		// Assume we specified a local image without the explicit storage transport.
-		fallthrough
-
-	case imageRef.Transport().Name() == storageTransport.Transport.Name():
-		br, err := registry.ImageEngine().Exists(registry.GetContext(), imageName)
-		if err != nil {
-			return "", err
-		}
-		imageMissing = !br.Value
-	}
-
 	if cliVals.Platform != "" || cliVals.Arch != "" || cliVals.OS != "" {
 		if cliVals.Platform != "" {
 			if cliVals.Arch != "" || cliVals.OS != "" {
@@ -273,31 +252,28 @@ func pullImage(imageName string) (string, error) {
 				cliVals.Arch = split[1]
 			}
 		}
+	}
 
-		if pullPolicy != config.PullPolicyAlways {
-			logrus.Info("--platform --arch and --os causes the pull policy to be \"always\"")
-			pullPolicy = config.PullPolicyAlways
-		}
+	pullReport, pullErr := registry.ImageEngine().Pull(registry.GetContext(), imageName, entities.ImagePullOptions{
+		Authfile:        cliVals.Authfile,
+		Quiet:           cliVals.Quiet,
+		Arch:            cliVals.Arch,
+		OS:              cliVals.OS,
+		Variant:         cliVals.Variant,
+		SignaturePolicy: cliVals.SignaturePolicy,
+		PullPolicy:      pullPolicy,
+	})
+	if pullErr != nil {
+		return "", pullErr
 	}
 
-	if imageMissing || pullPolicy == config.PullPolicyAlways {
-		if pullPolicy == config.PullPolicyNever {
-			return "", errors.Wrap(storage.ErrImageUnknown, imageName)
-		}
-		pullReport, pullErr := registry.ImageEngine().Pull(registry.GetContext(), imageName, entities.ImagePullOptions{
-			Authfile:        cliVals.Authfile,
-			Quiet:           cliVals.Quiet,
-			Arch:            cliVals.Arch,
-			OS:              cliVals.OS,
-			Variant:         cliVals.Variant,
-			SignaturePolicy: cliVals.SignaturePolicy,
-			PullPolicy:      pullPolicy,
-		})
-		if pullErr != nil {
-			return "", pullErr
-		}
+	// Return the input name such that the image resolves to correct
+	// repo/tag in the backend (see #8082).  Unless we're referring to
+	// the image via a transport.
+	if _, err := alltransports.ParseImageName(imageName); err == nil {
 		imageName = pullReport.Images[0]
 	}
+
 	return imageName, nil
 }