Call getaddrinfo from Ruby

`getaddrinfo` is notorious for not having a timeout, which can make
it hang for a very long time. Since Trilogy releases the GVL before
calling it, that can cause the whole VM to be unresponsive and no
longer respond to ctrl+c etc.

In 3.3.0, Ruby is now doing name resolution from a background thread,
making `Socket.getaddrinfo` interruptible. So by doing the name resolution
on the Ruby side, we should avoid such scenarios.

contrib/ruby/ext/trilogy-ruby/cext.c

@@ -25,7 +25,7 @@ static ID id_socket, id_host, id_port, id_username, id_password, id_found_rows,
     id_ivar_affected_rows, id_ivar_fields, id_ivar_last_insert_id, id_ivar_rows, id_ivar_query_time, id_password,
     id_database, id_ssl_ca, id_ssl_capath, id_ssl_cert, id_ssl_cipher, id_ssl_crl, id_ssl_crlpath, id_ssl_key,
     id_ssl_mode, id_tls_ciphersuites, id_tls_min_version, id_tls_max_version, id_multi_statement, id_multi_result,
-    id_from_code, id_from_errno, id_connection_options, id_max_allowed_packet;
+    id_from_code, id_from_errno, id_connection_options, id_max_allowed_packet, id_ip_address;
 
 struct trilogy_ctx {
     trilogy_conn_t conn;
@@ -488,6 +488,11 @@ static VALUE rb_trilogy_connect(VALUE self, VALUE encoding, VALUE charset, VALUE
             Check_Type(val, T_FIXNUM);
             connopt.port = NUM2USHORT(val);
         }
+
+        if ((val = rb_hash_lookup(opts, ID2SYM(id_ip_address))) != Qnil) {
+            Check_Type(val, T_STRING);
+            connopt.ip_address = StringValueCStr(val);
+        }
     } else {
         connopt.path = (char *)"/tmp/mysql.sock";
 
@@ -1184,6 +1189,7 @@ RUBY_FUNC_EXPORTED void Init_cext()
 
     id_socket = rb_intern("socket");
     id_host = rb_intern("host");
+    id_ip_address = rb_intern("ip_address");
     id_port = rb_intern("port");
     id_username = rb_intern("username");
     id_password = rb_intern("password");

contrib/ruby/lib/trilogy.rb

@@ -8,10 +8,23 @@
 
 class Trilogy
   def initialize(options = {})
+    options = options.dup
     options[:port] = options[:port].to_i if options[:port]
     mysql_encoding = options[:encoding] || "utf8mb4"
     encoding = Trilogy::Encoding.find(mysql_encoding)
     charset = Trilogy::Encoding.charset(mysql_encoding)
+
+    if options[:host]
+      addrs = begin
+        Socket.getaddrinfo(options[:host], options[:port], :PF_UNSPEC, :SOCK_STREAM)
+      rescue SocketError => error
+        raise Trilogy::BaseConnectionError, "Couldn't resolve host: #{options[:host].inspect}"
+      end
+
+      addrs.sort_by!(&:first) # Priority to IPv4
+      options[:ip_address] = addrs.first[3]
+    end
+
     @connection_options = options
     @connected_host = nil
 

contrib/ruby/test/client_test.rb

@@ -953,7 +953,7 @@ def test_connection_invalid_dns
     ex = assert_raises Trilogy::ConnectionError do
       new_tcp_client(host: "mysql.invalid", port: 3306)
     end
-    assert_equal "trilogy_connect - unable to connect to mysql.invalid:3306: TRILOGY_DNS_ERROR", ex.message
+    assert_includes ex.message, %{Couldn't resolve host: "mysql.invalid"}
   end
 
   def test_memsize

inc/trilogy/socket.h

@@ -36,6 +36,7 @@ typedef enum {
 
 typedef struct {
     char *hostname;
+    char *ip_address;
     char *path;
     char *database;
     char *username;

src/socket.c

@@ -341,7 +341,8 @@ int trilogy_sock_resolve(trilogy_sock_t *_sock)
         char port[6];
         snprintf(port, sizeof(port), "%hu", sock->base.opts.port);
 
-        if (getaddrinfo(sock->base.opts.hostname, port, &hint, &sock->addr) != 0) {
+        char *address = sock->base.opts.ip_address ? sock->base.opts.ip_address : sock->base.opts.hostname;
+        if (getaddrinfo(address, port, &hint, &sock->addr) != 0) {
             return TRILOGY_DNS_ERR;
         }
     } else if (sock->base.opts.path != NULL) {