Allow config sources to be specified for containerd

By default container extracts the current config by running
the `containerd config dump` command and if that fails
we read the existing config file.

This change allows ordering of these sources to be defined as
we do for the nvidia-ctk runtime configure command.

Signed-off-by: Evan Lezar <[email protected]>

Author: elezar

cmd/nvidia-ctk-installer/container/container.go

@@ -53,6 +53,8 @@ type Options struct {
 	SetAsDefault  bool
 	RestartMode   string
 	HostRootMount string
+
+	ConfigSources []string
 }
 
 // Configure applies the options to the specified config

cmd/nvidia-ctk-installer/container/runtime/containerd/containerd.go

@@ -172,12 +172,23 @@ func GetLowlevelRuntimePaths(o *container.Options, co *Options) ([]string, error
 }
 
 func getRuntimeConfig(o *container.Options, co *Options) (engine.Interface, error) {
+	var loaders []toml.Loader
+	for _, configSource := range o.ConfigSources {
+		switch configSource {
+		case "file":
+			loaders = append(loaders, toml.FromFile(o.TopLevelConfigPath))
+		case "command":
+			loaders = append(loaders, containerd.CommandLineSource(o.HostRootMount, o.ExecutablePath))
+		default:
+			return nil, fmt.Errorf("unsupported config source %q", configSource)
+		}
+	}
+
 	options := []containerd.Option{
 		containerd.WithTopLevelConfigPath(o.TopLevelConfigPath),
 		containerd.WithConfigSource(
 			toml.LoadFirst(
-				containerd.CommandLineSource(o.HostRootMount, o.ExecutablePath),
-				toml.FromFile(o.TopLevelConfigPath),
+				loaders...,
 			),
 		),
 		containerd.WithRuntimeType(co.runtimeType),

cmd/nvidia-ctk-installer/container/runtime/runtime.go

@@ -117,6 +117,12 @@ func Flags(opts *Options) []cli.Flag {
 			Sources:     cli.EnvVars("NVIDIA_RUNTIME_SET_AS_DEFAULT", "CONTAINERD_SET_AS_DEFAULT", "DOCKER_SET_AS_DEFAULT"),
 			Hidden:      true,
 		},
+		&cli.StringSliceFlag{
+			Name:        "config-source",
+			Usage:       "specify the config sources",
+			Destination: &opts.ConfigSources,
+			Sources:     cli.EnvVars("RUNTIME_CONFIG_SOURCES", "RUNTIME_CONFIG_SOURCE"),
+		},
 	}
 
 	flags = append(flags, containerd.Flags(&opts.containerdOptions)...)
@@ -167,6 +173,9 @@ func (opts *Options) Validate(logger logger.Interface, c *cli.Command, runtime s
 		if opts.RestartMode == runtimeSpecificDefault {
 			opts.RestartMode = containerd.DefaultRestartMode
 		}
+		if len(opts.ConfigSources) == 0 {
+			opts.ConfigSources = []string{"command", "file"}
+		}
 	case crio.Name:
 		if opts.TopLevelConfigPath == runtimeSpecificDefault {
 			opts.TopLevelConfigPath = crio.DefaultConfig