daemon: complete the "--graph" / "-g" deprecation

The `-g` / `--graph` options were soft deprecated in favor of `--data-root` in
261ef1fa27c4dfefa5f686b0a4ef354a43040e58 (v17.05.0) and at the time considered
to not be removed. However, with the move towards containerd snapshotters, having
these options around adds additional complexity to handle fallbacks for deprecated
(and hidden) flags, so completing the deprecation.

With this patch:

    dockerd --graph=/var/lib/docker --validate
    Flag --graph has been deprecated, Use --data-root instead
    unable to configure the Docker daemon with file /etc/docker/daemon.json: merged configuration validation from file and command line flags failed: the "graph" config file option is deprecated; use "data-root" instead

    mkdir -p /etc/docker
    echo '{"graph":"/var/lib/docker"}' > /etc/docker/daemon.json

    dockerd --validate
    unable to configure the Docker daemon with file /etc/docker/daemon.json: merged configuration validation from file and command line flags failed: the "graph" config file option is deprecated; use "data-root" instead

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

cmd/dockerd/config.go

@@ -65,10 +65,9 @@ func installCommonConfigFlags(conf *config.Config, flags *pflag.FlagSet) error {
 
 	// Deprecated flags / options
 
-	// "--graph" is "soft-deprecated" in favor of "data-root". This flag was added
-	// before Docker 1.0, so won't be removed, only hidden, to discourage its usage.
-	flags.StringVarP(&conf.Root, "graph", "g", conf.Root, "Root of the Docker runtime")
-	_ = flags.MarkHidden("graph")
+	//nolint:staticcheck // TODO(thaJeztah): remove in next release.
+	flags.StringVarP(&conf.RootDeprecated, "graph", "g", conf.RootDeprecated, "Root of the Docker runtime")
+	_ = flags.MarkDeprecated("graph", "Use --data-root instead")
 	flags.BoolVarP(&conf.AutoRestart, "restart", "r", true, "--restart on the daemon has been deprecated in favor of --restart policies on docker run")
 	_ = flags.MarkDeprecated("restart", "Please use a restart policy on docker run")
 

cmd/dockerd/daemon.go

@@ -397,9 +397,6 @@ func loadDaemonCliConfig(opts *daemonOptions) (*config.Config, error) {
 	conf.Hosts = opts.Hosts
 	conf.LogLevel = opts.LogLevel
 
-	if flags.Changed("graph") && flags.Changed("data-root") {
-		return nil, errors.New(`cannot specify both "--graph" and "--data-root" option`)
-	}
 	if flags.Changed(FlagTLS) {
 		conf.TLS = &opts.TLS
 	}
@@ -450,10 +447,6 @@ func loadDaemonCliConfig(opts *daemonOptions) (*config.Config, error) {
 		return nil, err
 	}
 
-	if flags.Changed("graph") {
-		logrus.Warnf(`The "-g / --graph" flag is deprecated. Please use "--data-root" instead`)
-	}
-
 	// Check if duplicate label-keys with different values are found
 	newLabels, err := config.GetConflictFreeLabels(conf.Labels)
 	if err != nil {

daemon/config/config.go

@@ -157,7 +157,7 @@ type CommonConfig struct {
 	NetworkDiagnosticPort int                       `json:"network-diagnostic-port,omitempty"`
 	Pidfile               string                    `json:"pidfile,omitempty"`
 	RawLogs               bool                      `json:"raw-logs,omitempty"`
-	RootDeprecated        string                    `json:"graph,omitempty"`
+	RootDeprecated        string                    `json:"graph,omitempty"` // Deprecated: use Root instead. TODO(thaJeztah): remove in next release.
 	Root                  string                    `json:"data-root,omitempty"`
 	ExecRoot              string                    `json:"exec-root,omitempty"`
 	SocketGroup           string                    `json:"group,omitempty"`
@@ -472,16 +472,6 @@ func getConflictFreeConfiguration(configFile string, flags *pflag.FlagSet) (*Con
 		return nil, err
 	}
 
-	if config.RootDeprecated != "" {
-		logrus.Warn(`The "graph" config file option is deprecated. Please use "data-root" instead.`)
-
-		if config.Root != "" {
-			return nil, errors.New(`cannot specify both "graph" and "data-root" config file options`)
-		}
-
-		config.Root = config.RootDeprecated
-	}
-
 	return &config, nil
 }
 
@@ -572,6 +562,11 @@ func findConfigurationConflicts(config map[string]interface{}, flags *pflag.Flag
 // such as config.DNS, config.Labels, config.DNSSearch,
 // as well as config.MaxConcurrentDownloads, config.MaxConcurrentUploads and config.MaxDownloadAttempts.
 func Validate(config *Config) error {
+	//nolint:staticcheck // TODO(thaJeztah): remove in next release.
+	if config.RootDeprecated != "" {
+		return errors.New(`the "graph" config file option is deprecated; use "data-root" instead`)
+	}
+
 	// validate log-level
 	if config.LogLevel != "" {
 		if _, err := logrus.ParseLevel(config.LogLevel); err != nil {