implement publish sub-cmd of mailinglist-cli

srv/cfg/cfg.go

@@ -19,12 +19,14 @@ type Cfg struct {
 	*flag.FlagSet
 
 	hooks []func(ctx context.Context) error
+	args  []string
 }
 
 // New initializes and returns a new instance of *Cfg.
 func New() *Cfg {
 	return &Cfg{
 		FlagSet: flag.NewFlagSet("", flag.ExitOnError),
+		args:    os.Args[1:],
 	}
 }
 
@@ -38,7 +40,7 @@ func (c *Cfg) OnInit(cb func(context.Context) error) {
 // called. If one returns an error that error is returned and no further hooks
 // are run.
 func (c *Cfg) Init(ctx context.Context) error {
-	if err := c.FlagSet.Parse(os.Args[1:]); err != nil {
+	if err := c.FlagSet.Parse(c.args); err != nil {
 		return err
 	}
 
@@ -50,3 +52,25 @@ func (c *Cfg) Init(ctx context.Context) error {
 
 	return nil
 }
+
+// SubCmd should be called _after_ Init. Init will have consumed all arguments
+// up until the first non-flag argument. This non-flag argument is a
+// sub-command, and is returned by this method. This method also resets Cfg's
+// internal state so that new options can be added to it.
+//
+// If there is no sub-command following the initial set of flags then this will
+// return empty string.
+func (c *Cfg) SubCmd() string {
+	c.args = c.FlagSet.Args()
+	if len(c.args) == 0 {
+		return ""
+	}
+
+	subCmd := c.args[0]
+
+	c.FlagSet = flag.NewFlagSet(subCmd, flag.ExitOnError)
+	c.hooks = nil
+	c.args = c.args[1:]
+
+	return subCmd
+}

srv/cmd/mailinglist-cli/main.go

@@ -68,14 +68,10 @@ func main() {
 	ml := mailinglist.New(mlParams)
 	_ = ml
 
-	args := cfg.Args()
-	if len(args) == 0 {
-		args = append(args, "")
-	}
-
-	action, args := args[0], args[1:]
+	subCmd := cfg.SubCmd()
+	ctx = mctx.Annotate(ctx, "subCmd", subCmd)
 
-	switch action {
+	switch subCmd {
 	case "list":
 		for it := mlStore.GetAll(); ; {
 			email, err := it()
@@ -94,7 +90,25 @@ func main() {
 			logger.Info(ctx, "next")
 		}
 
+	case "publish":
+
+		title := cfg.String("title", "", "Title of the post which was published")
+		url := cfg.String("url", "", "URL of the post which was published")
+		cfg.Init(ctx)
+
+		if *title == "" {
+			logger.Fatal(ctx, "-title is required")
+
+		} else if *url == "" {
+			logger.Fatal(ctx, "-url is required")
+		}
+
+		err := ml.Publish(*title, *url)
+		if err != nil {
+			loggerFatalErr(ctx, logger, "publishing", err)
+		}
+
 	default:
-		logger.Fatal(ctx, "invalid action")
+		logger.Fatal(ctx, "invalid sub-command, must be list|publish")
 	}
 }