[nydusify] Override source imageRef fetched from containerd (#22)

* [nydusify] Override source imageRef fetched from containerd

In case containerd has some hosts.toml specific configuration, the imageRef of
the containerId can be different to the actual url to fetch the image

This PR allow to override the imageRef fetched from containerd

Signed-off-by: Etienne Carriere <etienne.carriere@datadoghq.com>

* Change argument to source-image-ref

Signed-off-by: Etienne Carriere <etienne.carriere@datadoghq.com>

---------

Signed-off-by: Etienne Carriere <etienne.carriere@datadoghq.com>

Author: ecdatadog

contrib/nydusify/cmd/nydusify.go

@@ -1444,6 +1444,12 @@ func main() {
 					Usage:    "Target nydus image reference",
 					EnvVars:  []string{"TARGET"},
 				},
+				&cli.StringFlag{
+					Name:     "source-image-ref",
+					Required: false,
+					Usage:    "Override the source nydus image reference (useful when containerd uses hosts.toml remapping)",
+					EnvVars:  []string{"SOURCE_IMAGE_REF"},
+				},
 				&cli.BoolFlag{
 					Name:     "source-insecure",
 					Required: false,
@@ -1499,6 +1505,7 @@ func main() {
 					ContainerdAddress: c.String("containerd-address"),
 					Namespace:         c.String("namespace"),
 					ContainerID:       c.String("container"),
+					SourceImageRef:    c.String("source-image-ref"),
 					TargetRef:         c.String("target"),
 					SourceInsecure:    c.Bool("source-insecure"),
 					TargetInsecure:    c.Bool("target-insecure"),

contrib/nydusify/pkg/committer/commiter.go

@@ -46,6 +46,7 @@ type Opt struct {
 	Namespace         string
 
 	ContainerID    string
+	SourceImageRef string
 	SourceInsecure bool
 	TargetRef      string
 	TargetInsecure bool
@@ -104,6 +105,9 @@ func (cm *Committer) Commit(ctx context.Context, opt Opt) error {
 	}
 
 	originalSourceRef := inspect.Image
+	if opt.SourceImageRef != "" {
+		originalSourceRef = opt.SourceImageRef
+	}
 
 	logrus.Infof("pulling base bootstrap")
 	start := time.Now()