Add --envfile support for adapt command

Author: francislavoie

.gitignore

@@ -12,6 +12,7 @@ Caddyfile.*
 cmd/caddy/caddy
 cmd/caddy/caddy.exe
 cmd/caddy/tmp/*.exe
+cmd/caddy/.env
 
 # mac specific
 .DS_Store

cmd/commandfuncs.go

@@ -445,6 +445,21 @@ func cmdAdaptConfig(fl Flags) (int, error) {
 		return caddy.ExitCodeFailedStartup, err
 	}
 
+	var envfileFlag []string
+	envfileFlag, err = fl.GetStringSlice("envfile")
+	if err != nil {
+		return caddy.ExitCodeFailedStartup,
+			fmt.Errorf("reading envfile flag: %v", err)
+	}
+
+	// load all additional envs as soon as possible
+	for _, envfile := range envfileFlag {
+		if err := loadEnvFromFile(envfile); err != nil {
+			return caddy.ExitCodeFailedStartup,
+				fmt.Errorf("loading additional environment variables: %v", err)
+		}
+	}
+
 	if adapterFlag == "" {
 		return caddy.ExitCodeFailedStartup,
 			fmt.Errorf("adapter name is required (use --adapt flag or leave unspecified for default)")

cmd/commands.go

@@ -264,7 +264,7 @@ Environments may contain sensitive data.
 
 	RegisterCommand(Command{
 		Name:  "adapt",
-		Usage: "--config <path> [--adapter <name>] [--pretty] [--validate]",
+		Usage: "--config <path> [--adapter <name>] [--pretty] [--validate] [--envfile <path>]",
 		Short: "Adapts a configuration to Caddy's native JSON",
 		Long: `
 Adapts a configuration to Caddy's native JSON format and writes the
@@ -276,12 +276,16 @@ for human readability.
 If --validate is used, the adapted config will be checked for validity.
 If the config is invalid, an error will be printed to stderr and a non-
 zero exit status will be returned.
+
+If --envfile is specified, an environment file with environment variables in
+the KEY=VALUE format will be loaded into the Caddy process.
 `,
 		CobraFunc: func(cmd *cobra.Command) {
 			cmd.Flags().StringP("config", "c", "", "Configuration file to adapt (required)")
 			cmd.Flags().StringP("adapter", "a", "caddyfile", "Name of config adapter")
 			cmd.Flags().BoolP("pretty", "p", false, "Format the output for human readability")
 			cmd.Flags().BoolP("validate", "", false, "Validate the output")
+			cmd.Flags().StringSliceP("envfile", "", []string{}, "Environment file(s) to load")
 			cmd.RunE = WrapCommandFuncForCobra(cmdAdaptConfig)
 		},
 	})