fill in emailtouser

.gitignore

@@ -11,3 +11,4 @@ cmd/registeruser/registeruser
 cmd/stats/stats
 cmd/appendkeyfile/appendkeyfile
 cmd/help/help
+cmd/emailtouser/emailtouser

cmd/emailtouser/main.go

@@ -1,9 +1,40 @@
 package main
 
-import "fmt"
+import (
+	"errors"
+	"fmt"
+	"os"
 
-// TODO accept an email as an argument, write out a username associated with it or throw an error
+	"git.tilde.town/tildetown/town/towndb"
+)
+
+func _main(args []string) error {
+	if len(args) < 2 {
+		return errors.New("need email")
+	}
+	email := args[1]
+
+	db, err := towndb.ConnectDB()
+	if err != nil {
+		return err
+	}
+
+	user, err := towndb.UserForEmail(db, email)
+	if err != nil {
+		return err
+	}
+	if user == nil {
+		return errors.New("email does not correspond to user")
+	}
+
+	fmt.Println(user.Username)
+
+	return nil
+}
 
 func main() {
-	fmt.Println("TODO")
+	if err := _main(os.Args); err != nil {
+		fmt.Fprintf(os.Stderr, "%s\n", err.Error())
+		os.Exit(1)
+	}
 }