如何让 TLS 与 Erlang 21 一起工作

Question

我有以下问题：

炼金药

[centos@ip-172-172-3-49 helix]$ env MIX_ENV=prod mix release
Could not find Hex, which is needed to build dependency :plug_cowboy
Shall I install Hex? (if running non-interactively, use "mix local.hex --force") [Yn] Y
18:12:32.462 [info]  ['TLS', 32, 'client', 58, 32, 73, 110, 32, 115, 116, 97, 116, 101, 32, 'hello', 32, 'received SERVER ALERT: Fatal - Handshake Failure', 10]
** (Mix) httpc request failed with: {:failed_connect, [{:to_address, {'repo.hex.pm', 443}}, {:inet6, [:inet6], :enetunreach}, {:inet, [:inet], {:tls_alert, 'handshake failure'}}]}
Could not install Hex because Mix could not download metadata at https://repo.hex.pm/installs/hex-1.x.csv.

我想根本原因是 Erlang 的这个

Erlang/OTP 21 [erts-10.2.1] [source] [64-bit] [smp:36:36] [ds:36:36:10] [async-threads:1] [hipe]
1> ssl:start().
ok
2> Sock = fun() -> {ok, S} = gen_tcp:connect("google.com", 443, []), S end.
#Fun<erl_eval.20.128620087>
3>  ssl:connect(Sock(), []).
=INFO REPORT==== 28-Dec-2018::18:10:30.019612 ===
TLS client: In state hello received SERVER ALERT: Fatal - Handshake Failure
{error,{tls_alert,"handshake failure"}}

有没有解决方法？Os 是 Centos 7。

更新1

在MacOS上，它可以工作：

Erlang/OTP 21 [erts-10.2] [source] [64-bit] [smp:6:6] [ds:6:6:10] [async-threads:1] [hipe] [dtrace]
Eshell V10.2  (abort with ^G)
1> ssl:start().
ok
2>  Sock = fun() -> {ok, S} = gen_tcp:connect("google.com", 443, []), S end.
#Fun<erl_eval.20.128620087>
3>  ssl:connect(Sock(), []).
{ok,{sslsocket,{gen_tcp,#Port<0.6>,tls_connection,undefined},
               [<0.100.0>,<0.99.0>]}}
4>

Answer 1

事实证明，我使用的 Erlang RPM 不能正确支持 Erlang 中的新 SSL。

https://github.com/rabbitmq/erlang-rpm/releases/download/v21.2.1/erlang-21.2.1-1.el7.centos.x86_64.rpm

使用与 Erlang Solutions 不同的版本可以正常工作：

https://packages.erlang-solutions.com/erlang/esl-erlang/FLAVOUR_1_general/esl-erlang_21.2-1~centos~7_amd64.rpm

Answer 2

ssl：connect/2 描述如下： http://erlang.org/doc/man/ssl.html#connect-2.

连接非常简单：

ssl:start().
ssl:connect("www.google.com", 443, []).