There's a traceback when the username used to log via SMTPAUTH
in is not an email address:
=== before ===
```
[...] ERROR in app: Exception on /internal/auth/email [GET]
Traceback (most recent call last):
File "/usr/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 1179, in _execute_context
context = constructor(dialect, self, conn, *args)
File "/usr/lib/python3.9/site-packages/sqlalchemy/engine/default.py", line 719, in _init_compiled
param.append(processors[key](compiled_params[key]))
File "/usr/lib/python3.9/site-packages/sqlalchemy/sql/type_api.py", line 1201, in process
return process_param(value, dialect)
File "/app/mailu/models.py", line 60, in process_bind_param
localpart, domain_name = value.lower().rsplit('@', 1)
ValueError: not enough values to unpack (expected 2, got 1)
[...]
[parameters: [{'%(140657157923216 param)s': 'foobar'}]]
```
=== after ===
```
[...] WARNING in nginx: Invalid user 'foobar': (builtins.ValueError) invalid email address (no "@")
```
Allows to use mailu without docker-compose when hostnames are not set up
by docker itself but provided via a separate resolver.
Use case: use mailu using nomad scheduler and consul resolver instead of
docker-compose. Other servers are provided by the DNS resolver that
resolves names like admin.service.consul or webmail.service.consul.
These names needs to be configurable.
