net: add failed addresses + details on connect errors, make connect more robust in the default non blocking mode (#15364)

vlib/vweb/tests/vweb_test.v

@@ -269,6 +269,7 @@ fn simple_tcp_client(config SimpleTcpClientConfig) ?string {
 	mut tries := 0
 	for tries < config.retries {
 		tries++
+		eprintln('> client retries: $tries')
 		client = net.dial_tcp(localserver) or {
 			if tries > config.retries {
 				return err
@@ -278,6 +279,10 @@ fn simple_tcp_client(config SimpleTcpClientConfig) ?string {
 		}
 		break
 	}
+	if client == unsafe { nil } {
+		eprintln('coult not create a tcp client connection to $localserver after $config.retries retries')
+		exit(1)
+	}
 	client.set_read_timeout(tcp_r_timeout)
 	client.set_write_timeout(tcp_w_timeout)
 	defer {

vlib/vweb/tests/vweb_test_server.v

@@ -21,7 +21,7 @@ struct Config {
 
 fn exit_after_timeout(timeout_in_ms int) {
 	time.sleep(timeout_in_ms * time.millisecond)
-	// eprintln('webserver is exiting ...')
+	println('>> webserver: pid: $os.getpid(), exiting ...')
 	exit(0)
 }
 
@@ -43,7 +43,7 @@ fn main() {
 		timeout: timeout
 		global_config: config
 	}
-	eprintln('>> webserver: started on http://localhost:$app.port/ , with maximum runtime of $app.timeout milliseconds.')
+	eprintln('>> webserver: pid: $os.getpid(), started on http://localhost:$app.port/ , with maximum runtime of $app.timeout milliseconds.')
 	vweb.run_at(app, host: 'localhost', port: http_port, family: .ip)?
 }