Error connecting to mysql inside the docker about r2dbc-mysql HOT 4 OPEN

Sorry, I overlooked an important factor.

The hostname in the docker-compose.yaml file contains underscores, and r2dbc-spi cannot parse it correctly because java.net.URI cannot process it correctly. See also https://stackoverflow.com/questions/28568188 .

This causes DNS to resolve host "mysql_db:3306" instead of "mysql_db", so the resolution always fails.

Except for the first time, all my attempts were to write the docker-compose.yaml files myself, thus using hostnames without underscores, causing all my previous replies to be incorrect.

Strictly speaking, hostnames cannot contain underscores, so it's hard to tell whether this is intentional or not.

See:

• RFC 1123: "Requirements for Internet Hosts - Application and Support" - https://www.ietf.org/rfc/rfc1123.txt
• RFC 952: "DOD Internet Host Table Specification" - https://www.ietf.org/rfc/rfc952.txt

K8s service names also do not allow underscores: https://stackoverflow.com/questions/77514907

See also r2dbc/r2dbc-spi#280 , ConnectionUrlParser

import io.r2dbc.spi.ConnectionFactoryOptions;

public class ParsingMain {

    public static void main(String[] args) {
        ConnectionFactoryOptions o1 = ConnectionFactoryOptions.parse("r2dbc:mysql://underscore_db:3306");

        System.out.println(o1.getRequiredValue(ConnectionFactoryOptions.HOST));
        System.out.println(o1.getValue(ConnectionFactoryOptions.PORT));

        ConnectionFactoryOptions o2 = ConnectionFactoryOptions.parse("r2dbc:mysql://std-db:3306");

        System.out.println(o2.getRequiredValue(ConnectionFactoryOptions.HOST));
        System.out.println(o2.getValue(ConnectionFactoryOptions.PORT));

        URI u1 = URI.create("r2dbc://underscore_db:3306"); // ConnectionFactoryOptions.parse rewrites the URI

        System.out.println(u1.getHost()); // null
        System.out.println(u1.getPort()); // -1

        URI u2 = URI.create("r2dbc://std-db:3306");

        System.out.println(u2.getHost()); // std-db
        System.out.println(u2.getPort()); // 3306
    }
}

from r2dbc-mysql.

Seems to be caused by reactor-netty:1.1.9 on reactor-bom:2022.0.9. I had the same error and then when I tried upgrading it to reactor-bom:2022.0.16 this error gone. But I haven't seen any reports of this in reactor-netty or netty, more investigation is needed.

In addition, we should use reactor-netty-core instead of reactor-netty to slim dependencies. reactor-netty contains reactor-netty-http and reactor-netty-incubator-quic, which are not what we need.

It has been reproduced on Windows 11 and docker with eclipse-temurin:17-jdk-alpine image

2024-03-05: It cannot be reproduced on macOS 14.2.1 and docker 25.0.3 with eclipse-temurin:17-jdk image.

from r2dbc-mysql.

Would you mind letting me know what operating system, docker version, java image version in Dockerfile, and spring-data-r2dbc version you are using?

2024-03-06: Now it can be reproduced, a very inconspicuous configuration

from r2dbc-mysql.

Thank you so much for such a detailed answer, it helped me. I wish you success!!!

from r2dbc-mysql.