Consider changing the default for HTTPS to true on Consul.Builder, or remove it

[sleberknight]

If you do Consul.builder().build() you get an instance that uses only HTTP.

You must do this to get HTTPS:

var consul = Consul.builder()
    .withHttps(true)
    .build();

We should consider changing the default to be secure instead of insecure.

In addition, the withHttps method changes the scheme and possibly url fields, if already set by withMultipleHostAndPort.

Unfortunately, I think there is actually a subtle 🐛 here when withMultipleHostAndPort is used in combination with a different value for withHttps.

For example, suppose the Collection<HostAndPort> passed to withMultipleHostAndPort are all insecure HTTP URLs, but withHttps(true) is used. In this case, withHttps will set the scheme to "https" and change the url field to a new URL with the scheme as "https". But, it will not change anything in the Collection<HostAndPort>. If there is a connection error and a failover occurs, it will use the original URLs in the Collection<HostAndPort>, and thus will attempt the failover connection to an insecure HTTP URL!

Since this is a lot of complexity to change things that are already configured and having to reach into separate objects and change their internals, it might be better to simply remove the withHttps method, use "https" as the default, and put the onus on code that constructs the Consul instance to set the appropriate URLs (e.g., use "https" in all of them for secure connections).

For example, if you want only secure connections:

var hosts = buildHostAndPortsUsingOnlyHttps();
var consul = Consul.builder()
    .withMultipleHostAndPort(hosts, 10)
    .withSslContext(true)
    .build();

The main question to answer before doing this is what impact it will have to existing code, to simply change the default. While it really should default to secure, if it requires a lot of modifications to existing code, maybe it's not worth it to make the change.