mox retrain: make the parameter, for account, optional and retrain all accounts when absent

for more easily retraining all accounts. users should be retraining their
accounts with the next release, due to the fix in the previous commit.

ctl.go

@@ -1335,11 +1335,13 @@ func servectlcmd(ctx context.Context, ctl *ctl, shutdown func()) {
 	case "retrain":
 		/* protocol:
 		> "retrain"
-		> account
+		> account or empty
 		< "ok" or error
 		*/
 		account := ctl.xread()
-		acc, err := store.OpenAccount(log, account)
+
+		xretrain := func(name string) {
+			acc, err := store.OpenAccount(log, name)
 			ctl.xcheck(err, "open account")
 			defer func() {
 				if acc != nil {
@@ -1396,6 +1398,15 @@ func servectlcmd(ctx context.Context, ctl *ctl, shutdown func()) {
 				jf = nil
 				ctl.xcheck(err, "closing junk filter")
 			})
+		}
+
+		if account == "" {
+			for _, name := range mox.Conf.Accounts() {
+				xretrain(name)
+			}
+		} else {
+			xretrain(account)
+		}
 		ctl.xwriteok()
 
 	case "recalculatemailboxcounts":

doc.go

@@ -105,7 +105,7 @@ any parameters. Followed by the help and usage information for each command.
 	mox dnsbl check zone ip
 	mox dnsbl checkhealth zone
 	mox mtasts lookup domain
-	mox retrain accountname
+	mox retrain [accountname]
 	mox sendmail [-Fname] [ignoredflags] [-t] [<message]
 	mox spf check domain ip
 	mox spf lookup domain
@@ -1390,12 +1390,12 @@ should be used, and how long the policy can be cached.
 
 # mox retrain
 
-Recreate and retrain the junk filter for the account.
+Recreate and retrain the junk filter for the account or all accounts.
 
 Useful after having made changes to the junk filter configuration, or if the
 implementation has changed.
 
-	usage: mox retrain accountname
+	usage: mox retrain [accountname]
 
 # mox sendmail
 

main.go

@@ -2874,19 +2874,23 @@ should be used, and how long the policy can be cached.
 }
 
 func cmdRetrain(c *cmd) {
-	c.params = "accountname"
-	c.help = `Recreate and retrain the junk filter for the account.
+	c.params = "[accountname]"
+	c.help = `Recreate and retrain the junk filter for the account or all accounts.
 
 Useful after having made changes to the junk filter configuration, or if the
 implementation has changed.
 `
 	args := c.Parse()
-	if len(args) != 1 {
+	if len(args) > 1 {
 		c.Usage()
 	}
+	var account string
+	if len(args) == 1 {
+		account = args[0]
+	}
 
 	mustLoadConfig()
-	ctlcmdRetrain(xctl(), args[0])
+	ctlcmdRetrain(xctl(), account)
 }
 
 func ctlcmdRetrain(ctl *ctl, account string) {