Function runUse

cli/command/context/use.go:29–58

runUse set the current Docker context

(dockerCLI command.Cli, name string)

// runUse set the current Docker context
func runUse(dockerCLI command.Cli, name string) error {
	// configValue uses an empty string for "default"
	var configValue string
	if name != command.DefaultContextName {
		if err := store.ValidateContextName(name); err != nil {
			return err
		}
		if _, err := dockerCLI.ContextStore().GetMetadata(name); err != nil {
			return err
		}
		configValue = name
	}
	dockerConfig := dockerCLI.ConfigFile()
	// Avoid updating the config-file if nothing changed. This also prevents
	// creating the file and config-directory if the default is used and
	// no config-file existed yet.
	if dockerConfig.CurrentContext != configValue {
		dockerConfig.CurrentContext = configValue
		if err := dockerConfig.Save(); err != nil {
			return err
		}
	}
	_, _ = fmt.Fprintln(dockerCLI.Out(), name)
	_, _ = fmt.Fprintf(dockerCLI.Err(), "Current context is now %q\n", name)
	if name != command.DefaultContextName && os.Getenv(client.EnvOverrideHost) != "" {
		_, _ = fmt.Fprintf(dockerCLI.Err(), "Warning: %[1]s environment variable overrides the active context. "+
			"To use %[2]q, either set the global --context flag, or unset %[1]s environment variable.\n", client.EnvOverrideHost, name)
	}
	return nil
}