Allow file for config source to be specified explicitly

This change allows a "file" config source to also specify the source
path of the file to process. This means that when configuring containerd
with the option --config-source=file=/foo/bar.toml the file /foo/bar.toml
will be used as the source config instead of the output config file.

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

Author: elezar

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

@@ -21,6 +21,7 @@ import (
 	"fmt"
 	"os"
 	"os/exec"
+	"strings"
 
 	"github.com/sirupsen/logrus"
 
@@ -197,10 +198,22 @@ func (o Options) GetConfigLoaders(commandSourceFunc func(string, string) toml.Lo
 	}
 	var loaders []toml.Loader
 	for _, configSource := range o.ConfigSources {
-		switch configSource {
+		parts := strings.SplitN(configSource, "=", 2)
+		source := parts[0]
+		switch source {
 		case "file":
-			loaders = append(loaders, toml.FromFile(o.TopLevelConfigPath))
+			fileSourcePath := o.TopLevelConfigPath
+			if len(parts) > 1 {
+				fileSourcePath = parts[1]
+			}
+			loaders = append(loaders, toml.FromFile(fileSourcePath))
 		case "command":
+			if commandSourceFunc == nil {
+				logrus.Warnf("Ignoring command config source")
+			}
+			if len(parts) > 1 {
+				logrus.Warnf("Ignoring additional command argument %q", parts[1])
+			}
 			loaders = append(loaders, commandSourceFunc(o.HostRootMount, o.ExecutablePath))
 		default:
 			return nil, fmt.Errorf("unsupported config source %q", configSource)

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

@@ -118,9 +118,12 @@ func Flags(opts *Options) []cli.Flag {
 			Hidden:      true,
 		},
 		&cli.StringSliceFlag{
-			Name:        "config-source",
-			Aliases:     []string{"config-sources"},
-			Usage:       "Specify the config sources for the container runtime. Any combination of [command | file].",
+			Name:    "config-source",
+			Aliases: []string{"config-sources"},
+			Usage: "Specify the config sources for the container runtime. Any combination of " +
+				"[command | file]. " +
+				"When `file` is specifed, the absolute path to the file to be used as a config source can " +
+				"be specified as `file=/path/to/source/config.toml",
 			Value:       []string{"command", "file"},
 			Destination: &opts.ConfigSources,
 			Sources:     cli.EnvVars("RUNTIME_CONFIG_SOURCES", "RUNTIME_CONFIG_SOURCE"),