SNIHostName is going to throw an exception when hostname has a trailing dot

[seanmcnealy]

…ng dot

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Issue description

SSL SNI hostname with trailing dot unable to connect

New Public APIs

Additional context

Minor issue, as there is an easy workaround to disable SNI through configuration that avoids the issue entirely. The underlying library throws an error when there is a trailing dot on an SNI hostname. Looks easy enough to match that library's validation in the SSLConfig validation.

[mp911de]

How come that a host name returned from InetSocketAddress ends with a dot?

[seanmcnealy]

Looks like some DNS clients support adding a trailing dot which signifies to not use a search domain when resolving a name. I'm not an expert on this, I just have a coworker who used this convention when setting some environment variables.

I've tested 1.0.4 (works) and 1.0.5 (throws validation exception) with the following code:

import io.r2dbc.postgresql.PostgresqlConnectionConfiguration
import io.r2dbc.postgresql.PostgresqlConnectionFactory
import io.r2dbc.postgresql.client.SSLMode

val config =
    PostgresqlConnectionConfiguration.builder()
        .host("database.internal.")
        .port(5432)
        .database("reporting")
        .username("user")
        .password("xxxx")
        .sslMode(SSLMode.REQUIRE)
        .build()
val factory = PostgresqlConnectionFactory(config)

factory.create().block()

I could also see trimming trailing dots before sending to the SNIHostName constructor as valid. That would support SNI better, I think. Unless changing hostnames at all can cause more surprising results.

[mp911de]

Thank you for your contribution. That's merged, polished, and backported now.