[18.09] backport LCOW: --platform on import (already in API)

cli/command/image/import.go

@@ -19,6 +19,7 @@ type importOptions struct {
  reference string
  changes dockeropts.ListOpts
  message string
+ platform string
 }
 
 // NewImportCommand creates a new `docker import` command
@@ -43,6 +44,7 @@ func NewImportCommand(dockerCli command.Cli) *cobra.Command {
  options.changes = dockeropts.NewListOpts(nil)
  flags.VarP(&options.changes, "change", "c", "Apply Dockerfile instruction to the created image")
  flags.StringVarP(&options.message, "message", "m", "", "Set commit message for imported image")
+ command.AddPlatformFlag(flags, &options.platform)
 
  return cmd
 }
@@ -71,8 +73,9 @@ func runImport(dockerCli command.Cli, options importOptions) error {
  }
 
  importOptions := types.ImageImportOptions{
- Message: options.message,
- Changes: options.changes.GetAll(),
+ Message: options.message,
+ Changes: options.changes.GetAll(),
+ Platform: options.platform,
  }
 
  clnt := dockerCli.Client()

docs/reference/commandline/import.md

@@ -24,6 +24,7 @@ Options:
  -c, --change value Apply Dockerfile instruction to the created image (default [])
  --help Print usage
  -m, --message string Set commit message for imported image
+ --platform string Set platform if server is multi-platform capable
 ```
 
 ## Description
@@ -87,3 +88,11 @@ Note the `sudo` in this example – you must preserve
 the ownership of the files (especially root ownership) during the
 archiving with tar. If you are not root (or the sudo command) when you
 tar, then the ownerships might not get preserved.
+
+## When the daemon supports multiple operating systems
+If the daemon supports multiple operating systems, and the image being imported
+does not match the default operating system, it may be necessary to add
+`--platform`. This would be necessary when importing a Linux image into a Windows
+daemon.
+
+ # docker import --platform=linux .\linuximage.tar

man/src/image/import.md

@@ -38,5 +38,13 @@ This example sets the docker image ENV variable DEBUG to true by default.
 
  # tar -c . | docker image import -c="ENV DEBUG true" - exampleimagedir
 
+## When the daemon supports multiple operating systems
+If the daemon supports multiple operating systems, and the image being imported
+does not match the default operating system, it may be necessary to add
+`--platform`. This would be necessary when importing a Linux image into a Windows
+daemon.
+
+ # docker image import --platform=linux .\linuximage.tar
+
 # See also
 **docker-export(1)** to export the contents of a filesystem as a tar archive to STDOUT.