So I managed to get it working. First off, looking at the Erlang (R25) code this is wrong:
verify_fun: &:ssl_verify_hostname.verify_fun/3,
This works:
verify_fun: {&:ssl_verify_hostname.verify_fun/3, []},
I still have hostname validation errors, but in my case i don’t really care about that. So I added customize_hostname_check to make the (working) configuration look like:
[
verify: :verify_peer,
cacertfile: System.get_env("DB_SSL_CACERTFILE"),
customize_hostname_check: [match_fun: fn(_, _) -> true end],
verify_fun: {&:ssl_verify_hostname.verify_fun/3, []}
]
