Add config file support to CLI parser

Add -f/--config-file flag for loading YAML configs from local or remote sources. Fix error handling to return unmatched errors.

pkg/config/cli.go

@@ -1,6 +1,7 @@
 package config
 
 import (
+	"errors"
 	"flag"
 	"fmt"
 	"net/url"
@@ -52,14 +53,19 @@ Flags:
   -skip-verify      bool      Skip SSL/TLS certificate verification (default %v)`
 
 type ConfigCLIParser struct {
-	args []string
+	args       []string
+	configFile *types.ConfigFile
 }
 
 func NewConfigCLIParser(args []string) *ConfigCLIParser {
 	if args == nil {
 		args = []string{}
 	}
-	return &ConfigCLIParser{args}
+	return &ConfigCLIParser{args: args}
+}
+
+func (parser ConfigCLIParser) GetConfigFile() *types.ConfigFile {
+	return parser.configFile
 }
 
 type stringSliceArg []string
@@ -85,6 +91,7 @@ func (parser *ConfigCLIParser) Parse() (*Config, error) {
 
 	var (
 		config       = &Config{}
+		configFile   string
 		yes          bool
 		skipVerify   bool
 		method       string
@@ -101,6 +108,9 @@ func (parser *ConfigCLIParser) Parse() (*Config, error) {
 	)
 
 	{
+		flagSet.StringVar(&configFile, "config-file", "", "Config file")
+		flagSet.StringVar(&configFile, "f", "", "Config file")
+
 		flagSet.BoolVar(&yes, "yes", false, "Answer yes to all questions")
 		flagSet.BoolVar(&yes, "y", false, "Answer yes to all questions")
 
@@ -160,6 +170,29 @@ func (parser *ConfigCLIParser) Parse() (*Config, error) {
 	// Iterate over flags that were explicitly set on the command line.
 	flagSet.Visit(func(flagVar *flag.Flag) {
 		switch flagVar.Name {
+		case "config-file", "f":
+			var err error
+			parser.configFile, err = types.ParseConfigFile(configFile)
+			_ = utils.HandleErrorOrDie(err,
+				utils.OnSentinelError(types.ErrConfigFileExtensionNotFound, func(err error) error {
+					fieldParseErrors = append(fieldParseErrors, *types.NewFieldParseError("config-file", errors.New("file extension not found")))
+					return nil
+				}),
+				utils.OnCustomError(func(err types.RemoteConfigFileParseError) error {
+					fieldParseErrors = append(fieldParseErrors, *types.NewFieldParseError("config-file", fmt.Errorf("parse error: %w", err)))
+					return nil
+				}),
+				utils.OnCustomError(func(err types.UnknownConfigFileTypeError) error {
+					fieldParseErrors = append(
+						fieldParseErrors,
+						*types.NewFieldParseError(
+							"config-file",
+							fmt.Errorf("file type '%s' not supported (supported types: %s)", err.Type, types.ConfigFileTypeYAML.String()),
+						),
+					)
+					return nil
+				}),
+			)
 		case "yes", "y":
 			config.Yes = utils.ToPtr(yes)
 		case "skip-verify":